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RecruitingNCT05997615Updated Oct 27, 2026

Safety, Pharmacokinetics, and Preliminary Efficacy of VIR-5500 (AMX-500) in Prostate Cancer

A Phase 1 interventional study of VIR-5500 and Androgen receptor signaling inhibitor (ARSI) in Hormone-refractory Prostate Cancer, sponsored by Astellas Pharma Global Development, Inc.. Recruiting at 26 sites in 4 countries. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-27.

Sponsored by Astellas Pharma Global Development, Inc. (part of Astellas Pharma Inc) · Phase 1, Interventional, and Treatment

From the registry’s dates

  • Started Aug 2023; still recruiting 3 years 3 months later.
Updated Oct 27, 2026Primary completion movedStudy completion moved+7 moreGo to Updates ↓
Phase
Phase 1
Study type
Interventional
Enrollment
347
Allocation
Non-randomized
Ages
18 Years and older
Sex
Male
01

Study summary

There are many treatment options for men with various stages of prostate cancer. Some treatments work well for a while but can cause medical problems in some men. Also, the cancer may come back after treatment.

This is an early development study of VIR-5500 in men with prostate cancer. In this study, VIR-5500 will be given to people for the first time. VIR-5500 will either be given by itself or given together with one or more standard cancer treatments: enzalutamide, darolutamide and docetaxel. Some other cancer treatments may also be given with VIR-5500 during this study, depending on results from other ongoing studies.

Early development studies are mostly about safety, but also to find the most suitable dose. Other aims are to check if VIR-5500 shows signs of reducing tumor growth and to learn how the body processes VIR-5500. This will be done both for VIR-5500 given by itself and given together with the other cancer treatments.

The main aim(s) of the study are to check the safety of different doses of VIR-5500 when given by itself and given together with the standard cancer treatments, and how well it is tolerated; to find a suitable dose of VIR-5500 when given by itself and given together with the standard cancer treatments; to check the safety of VIR-5500 when given by itself to people in China and Japan; and to check how well VIR-5500 controls tumors when given by itself and given together with the standard cancer treatments.

Adult men with certain types of advanced prostate cancer can take part. Their cancer has spread to other parts of the body (metastatic). The different types of cancer in this study are: Metastatic hormone-sensitive prostate cancer (mHSPC). Prostate cancer that needs testosterone to grow; Metastatic castration-resistant prostate cancer (mCRPC). Prostate cancer that continues to grow even when testosterone levels are low; and High-risk biochemical recurrent prostate cancer (high-risk BRPC). Biochemical recurrence is a rise in PSA levels after treatment for prostate cancer. Men whose PSA levels double in less than 1 year are considered high risk of the cancer coming back and quickly getting worse.

In this study, VIR-5500 will be given to people for the first time. VIR-5500 will either be given itself or given together with at least one of the standard cancer treatments: enzalutamide, darolutamide, and docetaxel. The standard cancer treatment given will depend on which part of the study the men are in, and what type of prostate cancer they have. Other cancer treatments may be given, depending on results from other ongoing studies.

The study will have 4 parts.

In Part 1, different small groups of men with Metastatic castration-resistant prostate cancer (mCRPC) will receive lower to higher doses of VIR-5500 given by itself. Any medical problems will be recorded for each dose. This is to find out suitable doses to use in Part 2 of the study.

In Part 2, other small groups of men with mCRPC will receive the suitable doses of VIR-5500 worked out from Part 1. These men will have previously received specific cancer treatments before starting this study.

In Part 3, other different small groups of men with metastatic hormone-sensitive prostate cancer (mHSPC), mCRPC or high-risk BRPC will receive lower to higher doses of VIR-5500 given by itself or given with the other standard cancer treatments. They will be given VIR-5500 with enzalutamide or darolutamide, VIR-5500 with docetaxel, VIR-5500 with docetaxel and enzalutamide, or VIR- 5500 with docetaxel and darolutamide. Any medical problems will be recorded for each dose. This is to find out suitable doses to use in Part 4 of the study.

In Part 4, other small groups of men with mHSPC, mCRPC or high-risk biochemical recurrent prostate cancer (BRPC) will receive the suitable doses of VIR-5500 given together with the standard cancer treatments, worked out in Part 3. They will be given VIR-5500 with enzalutamide, VIR-5500 with darolutamide, VIR-5500 with docetaxel and enzalutamide, or VIR-5500 with docetaxel and darolutamide. The standard cancer treatment given will depend on their previous treatment before joining the study and the type of prostate cancer they have.

02

Conditions studied

  • Hormone-refractory Prostate Cancer

Keywords

  • Prostate Cancer
  • Castration Resistant Prostatic Cancer
  • High-Risk Biochemical Recurrent Prostate Cancer
  • Metastatic Castration-resistant Prostate Cancer (mCRPC)
  • Hormone Sensitive Prostate Cancer (HSPC)
  • Genital Neoplasms, Male
  • Urogenital Neoplasms
  • Neoplasms by Site
  • Neoplasms
  • Genital Diseases, Male
  • Genital Diseases
  • Urogenital Diseases
  • Prostatic Diseases
  • Male Urogenital Diseases
  • Prostatic Neoplasms
  • Prostatic Neoplasms, Castration-Resistant
03

In context

Prostatic Neoplasms

7,046 studies on the registry are indexed under Prostatic Neoplasms; 1,580 are open to participants now.

This study's planned enrollment of 347 is above the median of 60 across 5,348 interventional studies indexed under Prostatic Neoplasms.

Browse Prostatic Neoplasms studies →

Lead sponsor

Astellas Pharma Global Development, Inc. is the lead sponsor of 207 studies on the registry; 23 are open to participants now.

Of its 82 completed or terminated interventional studies of FDA-regulated products, 38 (46%) have results posted.

Browse Astellas Pharma Global Development, Inc. studies →All Astellas Pharma Inc studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

The criteria were revised on the registry on Oct 21, 2026. See what changed

Ages eligible
18 Years and older
Sexes eligible
Male
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

Inclusion Criteria Applicable to mCRPC Cohorts in Part 1 and PSMA-Targeted Radioligand-Naive mCRPC Cohort (Part 2 Cohort 2-2)

  • Have disease, defined by ≥ 1 metastatic lesion that is present on baseline computed tomography (CT), magnetic resonance imaging (MRI), or bone scan imaging
  • Have had prior bilateral orchiectomy and/or are receiving androgen deprivation therapy (ADT) and have a castrate level of serum testosterone (\< 50 ng/dL or \< 1.7 nmol/L)

  • Have documented progressive mCRPC based on ≥ 1 of the following criteria (per PCWG3):

    • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
    • Nodal or visceral progression as defined by v1.1 with PCWG3 modifications
    • Appearance of ≥ 2 new lesions in bone scan
  • Have been treated with ≥ 1 second-generation androgen-signaling inhibitor, including abiraterone, apalutamide, darolutamide, and/or enzalutamide
  • Have been treated with ≥ 1 prior taxane regimens (example (e.g.), docetaxel, cabazitaxel) in either mHSPC or mCRPC setting
  • Participants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
  • Are deemed unsuitable for standard of care (Only applicable for Part 1)

Inclusion Criteria Applicable for PSMA-Targeted Radioligand-Experienced mCRPC Cohort Only (Part 2 Cohort 2-1)

  • Have metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging

  • Have documented progressive disease (PD) based on ≥ 1 of the following criteria (per PCWG3):

    • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
    • Nodal or visceral progression, as defined by RECIST v1.1 with PCWG3 modifications
    • Appearance of ≥ 2 new lesions in bone scan
  • Have had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (\< 50 ng/dL or \< 1.7 nmol/L)
  • Have received PSMA-targeted radioligand-based therapy, such as 177Lu-PSMA-617 in any setting
  • Have been treated with ≥ 1 second-generation androgen-signaling inhibitor, including abiraterone, apalutamide, darolutamide, and/or enzalutamide
  • Have been treated with ≥ 1 prior taxane regimens (e.g., docetaxel, cabazitaxel) in either mHSPC or mCRPC setting
  • Participants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy

Inclusion Criteria Applicable for 1L/2L Taxane-Naïve mCRPC Cohorts Only (Cohort 2-3, Part 3, Cohort 4a-1, and Cohort 4b-1)

  • Prior treatment with ARSI (including but not limited to abiraterone, enzalutamide, darolutamide, or apalutamide). Participants without prior ARSI treatment in the mCRPC setting are also allowed
  • No prior exposure to taxane-based chemotherapy or other cytotoxic agents, including antibody-drug conjugates (ADCs) administered specifically for the treatment of mCRPC
  • Participants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
  • Have metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging

  • Have documented PD based on ≥ 1 of the following criteria (per PCWG3):

    • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
    • Nodal or visceral progression, as defined by RECIST v1.1 with PCWG3 modifications
    • Appearance of ≥ 2 new lesions in bone scan
  • Have had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (\< 50 ng/dL or \< 1.7 nmol/L)

Inclusion Criteria Applicable for mHSPC Cohorts Only (Part 3, Cohort 4a-2, and Cohort 4b-2)

  • documented prostate adenocarcinoma which is de novo or recurrent and considered castration-sensitive
  • Metastatic disease prior to first dose, with clear evidence of ≥ 1 bone lesion (defined as one lesion with positive uptake on bone scan) and/or ≥ 1 soft tissue lesion (measurable and/or non-measurable) that can be accurately assessed at baseline and is suitable for repeated assessment with CT and/or MRI. Participants with metastatic disease identified by PSMA-PET only, will not be eligible. Participants with disease limited to regional pelvic lymph nodes only are not eligible

  • Participants should have high-risk OR high-volume disease per the following criteria:

    • High-risk is defined as presence of at least 2 of the following: Gleason score of greater than or equal to (≥) 8; presence of 3 or more lesions on bone scan; presence of measurable visceral (excluding lymph node disease) metastasis on CT or MRI
    • High-volume disease is defined as: Presence of visceral metastases OR 4 bone lesions, with ≥1 beyond the vertebral bodies and pelvis
  • Participant is receiving ADT with a GnRH analogue or has undergone bilateral orchiectomy starting ≥ 14 days and \< 4 months prior to first dose with no radiographic evidence of disease progression or rising PSA levels prior to first day of dosing

Inclusion Criteria Applicable for High-Risk BRPC Cohorts Only (Dose Optimization, Part 3a, and Part 4a-3)

  • Have BRPC defined by meeting all of the following criteria:

    • Prostate cancer initially treated by radical prostatectomy or radiotherapy (including brachytherapy) or both, with curative intent
    • PSA doubling time ≤ 12 months at the time of study entry
    • Screening PSA ≥ 1 ng/mL in patients who have had radical prostatectomy (with or without radiotherapy) as primary treatment for prostate cancer and at least 2 ng/mL above the nadir in patients who had radiotherapy only as primary treatment for prostate cancer
    • Screening serum testosterone > 150 ng/dL

Inclusion Criteria Specific to Part 1a (Japanese Participants with mCRPC)

  • Participant is of Japanese descent and will be participating at a site in Japan
  • Have metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging
  • Have had prior bilateral orchiectomy and/or are receiving an ADT and have a castrate level of serum testosterone (\< 50 ng/dL or \< 1.7 nmol/L)

  • Have documented progressive mCRPC based on ≥ 1 of the following criteria (per PCWG3:

    • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
    • Nodal or visceral progression as defined by RECIST v1.1 with PCWG3 modifications
    • Appearance of ≥ 2 new lesions in bone scan
  • Have been treated with ≥ 1 second-generation androgen-signaling inhibitor, including but not limited to abiraterone, apalutamide, darolutamide, and/or enzalutamide
  • Have been treated with ≥ 1 prior taxane regimens (e.g., docetaxel, cabazitaxel) in either the mHSPC or mCRPC setting
  • Prior treatment with PSMA-targeted radioligand therapy, immunotherapy, sipuleucel-T, PARP inhibitors, and radium-223 is allowed
  • Participants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy

Inclusion Criteria Specific to Part 2a (Chinese Participants with mCRPC)

  • Participant is of Chinese descent and will be participating at a site in China
  • Have metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging
  • Have had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (\< 50 ng/dL or \< 1.7 nmol/L)

  • Have documented progressive mCRPC based on ≥ 1 of the following criteria (per PCWG3):

    • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
    • Nodal or visceral progression as defined by RECIST v1.1 with PCWG3 modifications
    • Appearance of ≥ 2 new lesions in bone scan
  • Have been treated with ≥ 1 second-generation androgen-signaling inhibitor, including but not limited to abiraterone, apalutamide, darolutamide, and/or enzalutamide
  • Have been treated with ≥ 1 prior taxane regimens (e.g., docetaxel, cabazitaxel) in either the mHSPC or mCRPC setting
  • Prior treatment with PSMA-targeted radioligand therapy, immunotherapy, sipuleucel-T, PARP inhibitors, and radium-223 is allowed
  • Participants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy

Exclusion criteria

Exclusion Criteria:

  • Have dominant histopathological features representative of sarcomatoid, spindle cell, or neuroendocrine small cell components
  • Have acute or chronic infections
  • Have a concomitant medical or inflammatory condition that may increase the risk of toxicity to VIR-5500 (AMX-500)
  • Have known active and/or carcinomatous meningitis
  • Have lesions in proximity of vital organs

Applicable to mHSPC cohorts only:

  • Any prior treatment with a GnRH analogue or ARSI
  • Any prior anticancer pharmacotherapy or surgery for prostate cancer

Exclusion Criteria Applicable to Part 3a and Part 4a Only: VIR-5500 (AMX-500) in Combination With an ARSI (Enzalutamide or Darolutamide)

  • Are progressing rapidly while taking a second-generation androgen-signaling inhibitor
  • Have a history or presence of CNS pathology within 12 months of enrollment
  • Have had significant cardiovascular disease within the last 3 months

Exclusion Criteria Applicable to Part 3b and Part 4b Only: VIR-5500 (AMX-500) in Combination With Docetaxel ± ARSI

  • Abnormal liver function test (LFT) values during screening
  • Currently receiving either strong or moderate inhibitors of cytochrome P450 (CYP)3A4 that cannot be discontinued for the duration of the study
Terms in these criteria, in plain language(5)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

RECIST

The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.

“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.

Histologically or cytologically confirmed

The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).

Your pathology report is the document that shows this.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

05

Study design

Phase
Phase 1
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Sequential assignment
Masking
None (open label)
Enrollment
347 participants (estimated)

Study arms

  • Experimental
    Part 1: VIR-5500 Monotherapy Dose Escalation

    VIR-5500 will be administered as a monotherapy in participants with mCRPC over a 21-day, 28-day or 42-day cycle.

    Drug: VIR-5500

  • Experimental
    Part 1a: VIR-5500 Monotherapy Japan Safety and PK Cohort

    VIR-5500 will be administered as a monotherapy in Japanese participants with mCRPC over a 21-day, 28-day or 42-day cycle.

    Drug: VIR-5500

  • Experimental
    Part 2: VIR-5500 Monotherapy Dose Expansion

    VIR-5500 will be administered as a monotherapy in participants with mCRPC over a 21-day, 28-day or 42-day cycle.

    Drug: VIR-5500

  • Experimental
    Part 2a: VIR-5500 Monotherapy China Safety and PK Expansion Cohort

    VIR-5500 will be administered as a monotherapy in Chinese participants with mCRPC over a 21-day. 28-day or 42-day cycle.

    Drug: VIR-5500

  • Experimental
    Part 3a: VIR-5500 in Combination with an ARSI for Dose Escalation

    VIR-5500 will be administered in combination with ARSI over a 21-day or 28-day cycle. ARSI will be administered every day.

    Drug: VIR-5500 · Drug: Androgen receptor signaling inhibitor (ARSI)

  • Experimental
    Part 3b: VIR-5500 in Combination with Docetaxel ± ARSI for Dose Escalation

    VIR-5500 will be administered in combination with docetaxel ± ARSI over a 21-day or 28-day cycle. Docetaxel will be administered once every 3 weeks for a maximum of 10 cycles for mCRPC and 6 cycles for mHSPC participants. ARSI may be included in the regimen at any stage administered per local label.

    Drug: VIR-5500 · Drug: Androgen receptor signaling inhibitor (ARSI) · Drug: Docetaxel

  • Experimental
    Part 4a: VIR-5500 in Combination with an ARSI for Dose Expansion

    VIR-5500 will be administered in combination with ARSI over a 21-day or 28-day cycle. ARSI will be administered twice daily.

    Drug: VIR-5500 · Drug: Androgen receptor signaling inhibitor (ARSI)

  • Experimental
    Part 4b: VIR-5500 in Combination with Docetaxel ± ARSI for Dose Expansion

    VIR-5500 will be administered in combination with docetaxel ± ARSI over a 21-day or 28-day cycle. Docetaxel will be administered once every 3 weeks for a maximum of 10 cycles for mCRPC and 6 cycles for mHSPC participants. ARSI may be included in the regimen at any stage administered per local label.

    Drug: VIR-5500 · Drug: Androgen receptor signaling inhibitor (ARSI) · Drug: Docetaxel

Interventions

  • DrugVIR-5500

    Pharmaceutical form: Solution for infusion Route of administration: Intravenous (IV) infusion

  • DrugAndrogen receptor signaling inhibitor (ARSI)

    Oral administration

  • DrugDocetaxel

    Pharmaceutical form: Solution for infusion Route of administration: Intravenous (IV) infusion

06

What researchers measure

Primary outcomes

  1. Part 1, 1a, 2a and Part 3: Number of Participants With Adverse Events (AEs) (mCRPC, mHSPC and BRPC)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. NOTE: An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease (new or exacerbated) temporally associated with the use of study intervention.

    Time frame: Up to 80 months

  2. Part 1, 1a, 2a and Part 3: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) (mCRPC, mHSPC and BRPC)

    TEAEs are adverse events that developed, worsened, or became serious from the start date of study treatment to the end date of study treatment plus (+) 30 days.

    Time frame: Up to 80 months

  3. Part 1, 1a and Part 3: Number of Participants With Dose-Limiting Toxicities (DLTs)

    A DLT is defined as any event meeting the DLT criteria.

    Time frame: Up to 28 Days

  4. Part 2 and 4: Prostate-Specific Antigen (PSA) Response Rate (PSA50) (mCRPC and mHSPC)

    PSA50 response rate is defined as a ≥ 50% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later.

    Time frame: Up to 80 months

  5. Part 2 and 4: Objective Response Rate (ORR) (mCRPC and mHSPC)

    ORR is defined as a proportion of participants who have complete response (CR) or partial response (PR) per investigator assessment using the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 with Prostate Cancer Working Group 3 (PCWG3) modifications.

    Time frame: Up to 80 months

  6. Part 4: PSA50 Response Rate (BRPC)

    PSA50 response rate is defined as a ≥ 50% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later.

    Time frame: Up to 80 months

  7. Part 4: Duration of PSA50 Response (BRPC)

    PSA50 is defined as a ≥ 50% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later. Duration of PSA50 response is defined as the period from the date of first documented \>= 50% reduction in PSA to the date of first documented \< 50% reduction in PSA, disease progression or death due to cause.

    Time frame: Up to 80 months

Secondary outcomes

  1. Part 2 and 4: Number of Participants With Adverse Events (AEs) (mCRPC, mHSPC and BRPC)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study intervention.

    Time frame: Up to 80 months

  2. Part 1, 1a, 2a and 3: Confirmed PSA50 Response Rate (mCRPC and mHSPC)

    PSA50 response rate is defined as a ≥ 50% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later.

    Time frame: Up to 80 months

  3. All Parts: Confirmed PSA90 Response Rate (mCRPC, mHSPC and BRPC)

    PSA90 response rate is defined as a ≥ 90% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later.

    Time frame: Up to 80 months

  4. Part 1, 1a, 2a and 3: Objective Response Rate (ORR) (mCRPC and mHSPC)

    ORR is defined as a proportion of participants who have either CR or PR per investigator assessment using the RECIST v1.1 with PCWG3 modifications.

    Time frame: Up to 80 months

  5. Part 1, 1a, 2, 2a, 3 and 4: Time to Response (TTR) (mCRPC and mHSPC)

    Time to response (TTR) is defined as the period from Cycle 1 Day 1 (C1D1) to the date of first either CR or PR per investigator assessment using the RECIST v1.1 with PCWG3 modifications.

    Time frame: Up to 80 months

  6. Part 1, 1a, 2, 2a, 3 and 4: Duration of Response (DOR) (mCRPC and mHSPC)

    Duration of response (DOR) is defined as the period from the date of first CR or PR per investigator assessment using the RECIST v1.1 with PCWG3 modifications to disease progression or death, whichever occurs first.

    Time frame: Up to 80 months

  7. Part 1, 1a, 2, 2a, 3 and 4: Radiographic Progression-Free Survival (PFS) (mCRPC and mHSPC)

    Radiographic progression-free survival (PFS) is defined as the period from C1D1 to disease progression or death, whichever occurs first, as evaluated by investigator assessment per RECIST v1.1 and PCWG3 criteria.

    Time frame: Up to 80 months

  8. All Parts: Time to PSA Progression (mCRPC, mHSPC and BRPC)

    Time to PSA progression per PCWG3 criteria, defined as an increase in PSA greater than 25% and \> 2 ng/mL above nadir.

    Time frame: Up to 80 months

  9. Part 1, 1a, 2, 2a, 3 and 4: Duration of PSA50 Response (mCRPC and mHSPC)

    PSA50 is defined as a ≥ 50% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later. Duration of PSA50 response is defined as the period from the date of first documented ≥ 50% reduction in PSA to the date of first documented \< 50% reduction in PSA, disease progression, or death due to any cause.

    Time frame: Up to 80 months

  10. All Parts: Duration of PSA90 Response (mCRPC, mHSPC and BRPC)

    PSA90 response rate is defined as a ≥ 90% reduction in PSA from baseline confirmed to be sustained by a second PSA value obtained 3 or more weeks later. Duration of PSA90 response is defined as the period from the date of first documented ≥ 90% reduction in PSA to the date of first documented \< 90% reduction in PSA, disease progression, or death due to any cause.

    Time frame: Up to 80 months

  11. Part 2 and 4: Rate for Undetectable PSA (mHSPC)

    Rate of undetectable PSA is defined as the proportion of participants who have a PSA of \< 0.2 ng/mL at 6 and 8 months.

    Time frame: Up to 8 months

  12. Part 4: Rate for Undetectable PSA (BRPC)

    Rate of undetectable PSA is defined as the proportion of participants who have a PSA of \< 0.2 ng/mL at 6, 12, and 24 months.

    Time frame: Up to 24 months

  13. All Parts: Pharmacokinetics (PK) of VIR-5500 in Plasma: Area Under the Concentration Time Curve (AUC) (mCRPC, mHSPC and BRPC)

    AUC will be recorded from PK plasma samples collected.

    Time frame: Up to 80 months

  14. All Parts: PK of VIR-5500 in Plasma: Maximum Observed Concentration (Cmax) (mCRPC, mHSPC and BRPC)

    Cmax will be recorded from PK plasma samples collected.

    Time frame: Up to 80 months

  15. All Parts: PK of VIR-5500 in Plasma: Time to Reach Maximum Concentration (tmax) (mCRPC, mHSPC and BRPC)

    Tmax will be recorded from PK plasma samples collected.

    Time frame: Up to 80 months

  16. All Parts: PK of VIR-5500 in Plasma: Trough Concentration (Ctrough) (mCRPC, mHSPC and BRPC)

    Ctrough will be recorded from PK Plasma samples collected.

    Time frame: Up to 80 months

  17. All Parts: Accumulation Ratio of VIR-5500 (mCRPC, mHSPC and BRPC)

    Accumulation ratio will be recorded from PK Plasma samples collected.

    Time frame: Up to 80 months

  18. All Parts: PK of VIR-5500 Metabolite in plasma: AUC (mCRPC, mHSPC and BRPC)

    AUC will be recorded from PK plasma samples collected.

    Time frame: Up to 80 months

  19. All Parts: PK of VIR-5500 Metabolite in Plasma: Cmax (mCRPC, mHSPC and BRPC)

    Cmax will be recorded from PK plasma samples collected.

    Time frame: Up to 80 months

  20. All Parts: PK of VIR-5500 Metabolite in plasma: tmax (mCRPC, mHSPC and BRPC)

    Tmax will be recorded from PK plasma samples collected.

    Time frame: Up to 80 months

  21. All Parts: PK of VIR-5500 metabolite in plasma: Ctrough (mCRPC, mHSPC and BRPC)

    Ctrough will be recorded from PK Plasma samples collected.

    Time frame: Up to 80 months

  22. All Parts: Accumulation Ratio of VIR-5500 metabolite (mCRPC, mHSPC and BRPC)

    Accumulation ratio will be recorded from PK Plasma samples collected.

    Time frame: Up to 80 months

07

Study locations

25 of 26 sites recruiting
  • Duarte Cancer Center
    Duarte, California 91010, United States
    Recruiting
  • University of California Irvine
    Irvine, California 92612, United States
    Recruiting
  • Lennar Foundation Cancer Center
    Irvine, California 92618, United States
    Recruiting
  • UCI Health Chao Family Comprehensive Cancer Center
    Orange, California 92862, United States
    Recruiting
  • Stanford University
    Palo Alto, California 94304, United States
    Recruiting
  • University of California
    San Francisco, California 94115, United States
    Recruiting
  • Chicago Cancer Center
    Zion, Illinois 60099, United States
    Recruiting
  • MD Anderson Cancer Center
    Houston, Texas 77030, United States
    Recruiting
  • NEXT Virginia
    Fairfax, Virginia 22031, United States
    Recruiting
  • Fred Hutchinson Cancer Research Center
    Seattle, Washington 98109, United States
    Recruiting
  • AU61002
    Darlinghurst, Australia
    Recruiting
  • AU61001
    Melbourne, Australia
    Recruiting
  • ES34001
    Barcelona, Spain
    Recruiting
  • ES34007
    Barcelona, Spain
    Recruiting
  • ES34015
    Barcelona, Spain
    Withdrawn

    Not enrolling at this site — choose another above.

  • ES34010
    Logroño, Spain
    Recruiting
  • ES34003
    Madrid, Spain
    Recruiting
  • ES34012
    Madrid, Spain
    Recruiting
  • ES34013
    Málaga, Spain
    Recruiting
  • ES34004
    Pamplona, Spain
    Recruiting
  • ES34002
    Pozuelo de Alarcón, Spain
    Recruiting
  • ES34005
    Sabadell, Spain
    Recruiting
  • ES34009
    Valencia, Spain
    Recruiting
  • GB44003
    Leicester, United Kingdom
    Recruiting
  • GB44001
    London, United Kingdom
    Recruiting
  • GB44004
    Newcastle, United Kingdom
    Recruiting
08

References and documents

Individual participant data

Plan to share: Yes — Access to anonymized individual participant level data collected during the study, in addition to study-related supporting documentation, is planned for studies conducted with approved product indications and formulations, as well as products terminated during development. Studies conducted with product indications or formulations that remain active in development are assessed after study completion to determine if Individual Participant Data can be shared. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.

Supporting information: Study protocol, Statistical analysis plan, Clinical study report

Time frame: Access to participant level data is offered to researchers after publication of the primary manuscript (if applicable) and is available as long as Astellas has legal authority to provide the data.

Access criteria: Researchers must submit a proposal to conduct a scientifically relevant analysis of the study data. The research proposal is reviewed by an Independent Research Panel. If the proposal is approved, access to the study data is provided in a secure data sharing environment after receipt of a signed Data Sharing Agreement.

Data sharing details ↗ · www.clinicaltrials.astellas.com

No publications or documents are linked to this record.

09

Timeline

3 registry updates since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedDate before it movedWhere the date was before it movedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Aug 2023 (actual). Primary completion is estimated for Sep 2027, 49 months after the start.

Of 212 industry-sponsored phase 1 interventional studies under Prostatic Neoplasms, half reached primary completion within 37 months of starting (the median), counting those still running; a quarter within 20 and three quarters within 62. This study's planned 49 months is above that.

Counting every sponsor, half of 455 studies reached it within 43 months; a quarter within 23 and three quarters within 68.

Completion moved once since we started tracking on Sep 25, 2026: Sep 2027 → Jun 2030, on Oct 21, 2026.

Earlier changes are on the record history on ClinicalTrials.gov ↗

How these figures are worked out, and which studies are left out of them.

Registered
Jul 24, 2023
First posted
Aug 18, 2023
StartActual
Aug 10, 2023
Primary completionEst.
Sep 30, 2027
CompletionEst.
Jun 30, 2030was Sep 2027
Last update
Oct 27, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
Sites
25 sites added, 12 sites removed
Show 25 added (11 Spain, 9 United States, 3 United Kingdom, 2 Australia)
  • Duarte Cancer Center · Duarte, United States
  • Lennar Foundation Cancer Center · Irvine, United States
  • Chicago Cancer Center · Zion, United States
  • ES34007 · Barcelona, Spain
  • ES34010 · Logroño, Spain
  • ES34012 · Madrid, Spain
  • ES34013 · Málaga, Spain
  • ES34009 · Valencia, Spain
  • GB44003 · Leicester, United Kingdom
  • Stanford University · Palo Alto, United States
  • University of California · San Francisco, United States
  • MD Anderson Cancer Center · Houston, United States
  • NEXT Virginia · Fairfax, United States
  • Fred Hutchinson Cancer Research Center · Seattle, United States
  • AU61002 · Darlinghurst, Australia
  • AU61001 · Melbourne, Australia
  • ES34001 · Barcelona, Spain
  • ES34015 · Barcelona, Spain
  • ES34003 · Madrid, Spain
  • ES34004 · Pamplona, Spain
  • ES34002 · Pozuelo de Alarcón, Spain
  • ES34005 · Sabadell, Spain
  • GB44001 · London, United Kingdom
  • University of California Irvine · Irvine, United States
  • GB44004 · Newcastle, United Kingdom
Show 12 removed
  • Investigational Site Number: 403 · Palo Alto, United States
  • Investigational Site Number: 401 · Houston, United States
  • Investigational Site number: 404 · Fairfax, United States
  • Investigational Site Number: 400 · Seattle, United States
  • Investigational Site Number: 100 · Melbourne, Australia
  • Investigational Site Number: 101 · Sydney, Australia
  • Investigational Site Number: 251 · Barcelona, Spain
  • Investigational Site Number: 250 · Barcelona, Spain
  • Investigational Site Number: 254 · Madrid, Spain
  • Investigational Site Number: 252 · Madrid, Spain
  • Investigational Site Number: 253 · Pamplona, Spain
  • Investigational Site Number: 300 · London, United Kingdom
across 3 updates, Oct 7, 2026 – Oct 27, 2026
Primary completion
Sep 29, 2027→Sep 30, 2027
Oct 21, 2026
Study completion
Sep 29, 2027→Jun 30, 2030
Oct 21, 2026
Enrollment
437→347
Oct 21, 2026
Eligibility
Criteria largely rewritten (79 changes)
What changed in the criteria
Inclusion criteria
  • ChangedBefore Applicable to Parts 1 and 2Now Inclusion Criteria Applicable to mCRPC Cohorts in Part 1 and PSMA-Targeted Radioligand-Naive mCRPC Cohort (Part 2 Cohort 2-2)
  • AddedHave had prior bilateral orchiectomy and/or are receiving androgen deprivation therapy (ADT) and have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
  • EditedHave documented progressive mCRPC based on ≥ 1 of the following criteria (per PCWG3):
  • AddedHave been treated with ≥ 1 prior taxane regimens (example (e.g.), docetaxel, cabazitaxel) in either mHSPC or mCRPC setting
  • AddedParticipants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
  • EditedAre deemed unsuitable for standard of care (Only applicable for Part 1)
  • RemovedApplicable to Part 2, 3a and Part 4a,
  • AddedInclusion Criteria Applicable for PSMA-Targeted Radioligand-Experienced mCRPC Cohort Only (Part 2 Cohort 2-1)
  • EditedHave metastatic CRPCdisease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging that has documented progressive disease (PD) based on ≥ 1 of the following criteria (per PCWG3):
  • AddedHave documented progressive disease (PD) based on ≥ 1 of the following criteria (per PCWG3):
  • AddedNodal or visceral progression, as defined by RECIST v1.1 with PCWG3 modifications
  • RemovedParticipants with metastatic hormone sensitive prostate cancer (mHSPC) or with biochemical recurrent prostate cancer (BRPC) may also participate in select cohorts of this clinical trial.
  • AddedHave had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
  • AddedHave received PSMA-targeted radioligand-based therapy, such as 177Lu-PSMA-617 in any setting
  • AddedHave been treated with ≥ 1 second-generation androgen-signaling inhibitor, including abiraterone, apalutamide, darolutamide, and/or enzalutamide
  • EditedHave been treated with ≥ 1 prior taxane regimens (e.g., docetaxel, cabazitaxel) in either mHSPC or mCRPC setting
  • AddedParticipants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
  • AddedInclusion Criteria Applicable for 1L/2L Taxane-Naïve mCRPC Cohorts Only (Cohort 2-3, Part 3, Cohort 4a-1, and Cohort 4b-1)
  • AddedPrior treatment with ARSI (including but not limited to abiraterone, enzalutamide, darolutamide, or apalutamide). Participants without prior ARSI treatment in the mCRPC setting are also allowed
  • AddedNo prior exposure to taxane-based chemotherapy or other cytotoxic agents, including antibody-drug conjugates (ADCs) administered specifically for the treatment of mCRPC
  • AddedParticipants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
  • AddedHave metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging
  • AddedHave documented PD based on ≥ 1 of the following criteria (per PCWG3):
  • AddedPSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
  • AddedNodal or visceral progression, as defined by RECIST v1.1 with PCWG3 modifications
  • AddedAppearance of ≥ 2 new lesions in bone scan
  • AddedHave had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
  • AddedInclusion Criteria Applicable for mHSPC Cohorts Only (Part 3, Cohort 4a-2, and Cohort 4b-2)
  • AddedHistologically documented prostate adenocarcinoma which is de novo or recurrent and considered castration-sensitive
  • AddedMetastatic disease prior to first dose, with clear evidence of ≥ 1 bone lesion (defined as one lesion with positive uptake on bone scan) and/or ≥ 1 soft tissue lesion (measurable and/or non-measurable) that can be accurately assessed at baseline and is suitable for repeated assessment with CT and/or MRI. Participants with metastatic disease identified by PSMA-PET only, will not be eligible. Participants with disease limited to regional pelvic lymph nodes only are not eligible
  • AddedParticipants should have high-risk OR high-volume disease per the following criteria:
  • AddedHigh-risk is defined as presence of at least 2 of the following: Gleason score of greater than or equal to (≥) 8; presence of 3 or more lesions on bone scan; presence of measurable visceral (excluding lymph node disease) metastasis on CT or MRI
  • AddedHigh-volume disease is defined as: Presence of visceral metastases OR 4 bone lesions, with ≥1 beyond the vertebral bodies and pelvis
  • AddedParticipant is receiving ADT with a GnRH analogue or has undergone bilateral orchiectomy starting ≥ 14 days and < 4 months prior to first dose with no radiographic evidence of disease progression or rising PSA levels prior to first day of dosing
  • AddedInclusion Criteria Applicable for High-Risk BRPC Cohorts Only (Dose Optimization, Part 3a, and Part 4a-3)
  • AddedHave BRPC defined by meeting all of the following criteria:
  • AddedProstate cancer initially treated by radical prostatectomy or radiotherapy (including brachytherapy) or both, with curative intent
  • AddedPSA doubling time ≤ 12 months at the time of study entry
  • AddedScreening PSA ≥ 1 ng/mL in patients who have had radical prostatectomy (with or without radiotherapy) as primary treatment for prostate cancer and at least 2 ng/mL above the nadir in patients who had radiotherapy only as primary treatment for prostate cancer
  • AddedScreening serum testosterone > 150 ng/dL

…and 39 more changes, on the record history on ClinicalTrials.gov ↗

Oct 21, 2026
Interventions
Added Drug: Docetaxel. Arm changed Part 4a: VIR-5500 in combination with an ARSI for Dose Expansion→Part 3b: VIR-5500 in Combination with Docetaxel ± ARSI for Dose Escalation. Arms added: Part 1a: VIR-5500 Monotherapy Japan Safety and PK Cohort·Part 2a: VIR-5500 Monotherapy China Safety and PK Expansion Cohort·Part 4a: VIR-5500 in Combination with an ARSI for Dose Expansion·Part 4b: VIR-5500 in Combination with Docetaxel ± ARSI for Dose Expansion
Oct 21, 2026
Primary outcomes
4 edited, 3 added, 1 removed
What changed in the outcomes
  • EditedPart 1, 1a and 3aPart 3: IncidenceNumber of Participants With Dose -Limiting Toxicities (DLTs)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to Day 21 or Day 28 → Up to 28 Days
  • EditedPart 2 and 4a4: Prostate-Specific Antigen (PSA) response rateResponse Rate (PSA50) (mCRPC and mHSPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
  • EditedPart 2 and 4a4: Objective Response Rate (ORR) (mCRPC and mHSPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
  • EditedPart 1, 1a, 2a and 3aPart 3: Number of participants with treatment-emergentParticipants With Adverse Events (AEs) (mCRPC, mHSPC and BRPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
  • AddedPart 1, 1a, 2a and Part 3: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedPart 4: PSA50 Response Rate (BRPC)Time frame: Up to 80 months
  • AddedPart 4: Duration of PSA50 Response (BRPC)Time frame: Up to 80 months
  • RemovedAll parts: Incidence of treatment emergent anti-drug antibodies (ADAs) to VIR-5500Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
Oct 21, 2026
Secondary outcomes
3 edited, 19 added, 7 removed
What changed in the outcomes
  • EditedPart 2 and 4a4: Number of participants withParticipants With Adverse Events (AEs) (mCRPC, mHSPC and BRPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
  • EditedPart 1, 1a, 2a and 3a3: ObjectiveConfirmed PSA50 Response Rate (ORRmCRPC and mHSPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
  • EditedAll partsParts: Duration of responsePSA90 Response (DoRmCRPC, mHSPC and BRPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
  • AddedAll Parts: Confirmed PSA90 Response Rate (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedPart 1, 1a, 2a and 3: Objective Response Rate (ORR) (mCRPC and mHSPC)Time frame: Up to 80 months
  • AddedPart 1, 1a, 2, 2a, 3 and 4: Time to Response (TTR) (mCRPC and mHSPC)Time frame: Up to 80 months
  • AddedPart 1, 1a, 2, 2a, 3 and 4: Duration of Response (DOR) (mCRPC and mHSPC)Time frame: Up to 80 months
  • AddedPart 1, 1a, 2, 2a, 3 and 4: Radiographic Progression-Free Survival (PFS) (mCRPC and mHSPC)Time frame: Up to 80 months
  • AddedAll Parts: Time to PSA Progression (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedPart 1, 1a, 2, 2a, 3 and 4: Duration of PSA50 Response (mCRPC and mHSPC)Time frame: Up to 80 months
  • AddedPart 2 and 4: Rate for Undetectable PSA (mHSPC)Time frame: Up to 8 months
  • AddedPart 4: Rate for Undetectable PSA (BRPC)Time frame: Up to 24 months
  • AddedAll Parts: Pharmacokinetics (PK) of VIR-5500 in Plasma: Area Under the Concentration Time Curve (AUC) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 in Plasma: Maximum Observed Concentration (Cmax) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 in Plasma: Time to Reach Maximum Concentration (tmax) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 in Plasma: Trough Concentration (Ctrough) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: Accumulation Ratio of VIR-5500 (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 Metabolite in plasma: AUC (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 Metabolite in Plasma: Cmax (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 Metabolite in plasma: tmax (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: PK of VIR-5500 metabolite in plasma: Ctrough (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • AddedAll Parts: Accumulation Ratio of VIR-5500 metabolite (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
  • RemovedPart 1 and 3a: PSA response rateTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
  • RemovedAll parts: Progression Free Survival PFSTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
  • RemovedAll parts: Assessment of PK parameters: CmaxTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
  • RemovedAll parts: Assessment of PK parameters: AUCTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
  • RemovedAll parts: Assessment of PK parameters: TmaxTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
  • RemovedAll parts: Incidence of baseline anti-drug antibodies (ADAs) to VIR-5500Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
  • RemovedAll parts: Incidence of treatment emergent anti-drug antibodies (ADAs) to VIR-5500Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
Oct 21, 2026
Contact
Study contact changed: c•••@vir.bio · •••5281→A•••@astellas.com · •••7704. See the current contact
Oct 21, 2026
Show all 3 updates
  1. Oct 27, 2026
    2 sites added
    Show 2 added (1 United States, 1 United Kingdom)
    • University of California Irvine · Irvine, United States
    • GB44004 · Newcastle, United Kingdom
  2. Oct 21, 2026
    14 sites added, 12 sites removed
    Show 14 added (6 Spain, 5 United States, 2 Australia, 1 United Kingdom)
    • Stanford University · Palo Alto, United States
    • University of California · San Francisco, United States
    • MD Anderson Cancer Center · Houston, United States
    • NEXT Virginia · Fairfax, United States
    • Fred Hutchinson Cancer Research Center · Seattle, United States
    • AU61002 · Darlinghurst, Australia
    • AU61001 · Melbourne, Australia
    • ES34001 · Barcelona, Spain
    • ES34015 · Barcelona, Spain
    • ES34003 · Madrid, Spain
    • ES34004 · Pamplona, Spain
    • ES34002 · Pozuelo de Alarcón, Spain
    • ES34005 · Sabadell, Spain
    • GB44001 · London, United Kingdom
    Show 12 removed
    • Investigational Site Number: 403 · Palo Alto, United States
    • Investigational Site Number: 401 · Houston, United States
    • Investigational Site number: 404 · Fairfax, United States
    • Investigational Site Number: 400 · Seattle, United States
    • Investigational Site Number: 100 · Melbourne, Australia
    • Investigational Site Number: 101 · Sydney, Australia
    • Investigational Site Number: 251 · Barcelona, Spain
    • Investigational Site Number: 250 · Barcelona, Spain
    • Investigational Site Number: 254 · Madrid, Spain
    • Investigational Site Number: 252 · Madrid, Spain
    • Investigational Site Number: 253 · Pamplona, Spain
    • Investigational Site Number: 300 · London, United Kingdom
    Primary completion Sep 29, 2027→Sep 30, 2027
    Study completion Sep 29, 2027→Jun 30, 2030
    Enrollment 437→347
    Eligibility Criteria largely rewritten (79 changes)
    What changed in the criteria
    Inclusion criteria
    • ChangedBefore Applicable to Parts 1 and 2Now Inclusion Criteria Applicable to mCRPC Cohorts in Part 1 and PSMA-Targeted Radioligand-Naive mCRPC Cohort (Part 2 Cohort 2-2)
    • AddedHave had prior bilateral orchiectomy and/or are receiving androgen deprivation therapy (ADT) and have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
    • EditedHave documented progressive mCRPC based on ≥ 1 of the following criteria (per PCWG3):
    • AddedHave been treated with ≥ 1 prior taxane regimens (example (e.g.), docetaxel, cabazitaxel) in either mHSPC or mCRPC setting
    • AddedParticipants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
    • EditedAre deemed unsuitable for standard of care (Only applicable for Part 1)
    • RemovedApplicable to Part 2, 3a and Part 4a,
    • AddedInclusion Criteria Applicable for PSMA-Targeted Radioligand-Experienced mCRPC Cohort Only (Part 2 Cohort 2-1)
    • EditedHave metastatic CRPCdisease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging that has documented progressive disease (PD) based on ≥ 1 of the following criteria (per PCWG3):
    • AddedHave documented progressive disease (PD) based on ≥ 1 of the following criteria (per PCWG3):
    • AddedNodal or visceral progression, as defined by RECIST v1.1 with PCWG3 modifications
    • RemovedParticipants with metastatic hormone sensitive prostate cancer (mHSPC) or with biochemical recurrent prostate cancer (BRPC) may also participate in select cohorts of this clinical trial.
    • AddedHave had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
    • AddedHave received PSMA-targeted radioligand-based therapy, such as 177Lu-PSMA-617 in any setting
    • AddedHave been treated with ≥ 1 second-generation androgen-signaling inhibitor, including abiraterone, apalutamide, darolutamide, and/or enzalutamide
    • EditedHave been treated with ≥ 1 prior taxane regimens (e.g., docetaxel, cabazitaxel) in either mHSPC or mCRPC setting
    • AddedParticipants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
    • AddedInclusion Criteria Applicable for 1L/2L Taxane-Naïve mCRPC Cohorts Only (Cohort 2-3, Part 3, Cohort 4a-1, and Cohort 4b-1)
    • AddedPrior treatment with ARSI (including but not limited to abiraterone, enzalutamide, darolutamide, or apalutamide). Participants without prior ARSI treatment in the mCRPC setting are also allowed
    • AddedNo prior exposure to taxane-based chemotherapy or other cytotoxic agents, including antibody-drug conjugates (ADCs) administered specifically for the treatment of mCRPC
    • AddedParticipants with known mutations in BRCA1/2 must have received a PARP inhibitor if an approved therapy is locally available, and participant is considered suitable for this therapy
    • AddedHave metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging
    • AddedHave documented PD based on ≥ 1 of the following criteria (per PCWG3):
    • AddedPSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
    • AddedNodal or visceral progression, as defined by RECIST v1.1 with PCWG3 modifications
    • AddedAppearance of ≥ 2 new lesions in bone scan
    • AddedHave had prior bilateral orchiectomy and/or are receiving ADT and have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
    • AddedInclusion Criteria Applicable for mHSPC Cohorts Only (Part 3, Cohort 4a-2, and Cohort 4b-2)
    • AddedHistologically documented prostate adenocarcinoma which is de novo or recurrent and considered castration-sensitive
    • AddedMetastatic disease prior to first dose, with clear evidence of ≥ 1 bone lesion (defined as one lesion with positive uptake on bone scan) and/or ≥ 1 soft tissue lesion (measurable and/or non-measurable) that can be accurately assessed at baseline and is suitable for repeated assessment with CT and/or MRI. Participants with metastatic disease identified by PSMA-PET only, will not be eligible. Participants with disease limited to regional pelvic lymph nodes only are not eligible
    • AddedParticipants should have high-risk OR high-volume disease per the following criteria:
    • AddedHigh-risk is defined as presence of at least 2 of the following: Gleason score of greater than or equal to (≥) 8; presence of 3 or more lesions on bone scan; presence of measurable visceral (excluding lymph node disease) metastasis on CT or MRI
    • AddedHigh-volume disease is defined as: Presence of visceral metastases OR 4 bone lesions, with ≥1 beyond the vertebral bodies and pelvis
    • AddedParticipant is receiving ADT with a GnRH analogue or has undergone bilateral orchiectomy starting ≥ 14 days and < 4 months prior to first dose with no radiographic evidence of disease progression or rising PSA levels prior to first day of dosing
    • AddedInclusion Criteria Applicable for High-Risk BRPC Cohorts Only (Dose Optimization, Part 3a, and Part 4a-3)
    • AddedHave BRPC defined by meeting all of the following criteria:
    • AddedProstate cancer initially treated by radical prostatectomy or radiotherapy (including brachytherapy) or both, with curative intent
    • AddedPSA doubling time ≤ 12 months at the time of study entry
    • AddedScreening PSA ≥ 1 ng/mL in patients who have had radical prostatectomy (with or without radiotherapy) as primary treatment for prostate cancer and at least 2 ng/mL above the nadir in patients who had radiotherapy only as primary treatment for prostate cancer
    • AddedScreening serum testosterone > 150 ng/dL

    …and 39 more changes, on the record history on ClinicalTrials.gov ↗

    Primary outcomes 4 edited, 3 added, 1 removed
    What changed in the outcomes
    • EditedPart 1, 1a and 3aPart 3: IncidenceNumber of Participants With Dose -Limiting Toxicities (DLTs)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to Day 21 or Day 28 → Up to 28 Days
    • EditedPart 2 and 4a4: Prostate-Specific Antigen (PSA) response rateResponse Rate (PSA50) (mCRPC and mHSPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
    • EditedPart 2 and 4a4: Objective Response Rate (ORR) (mCRPC and mHSPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
    • EditedPart 1, 1a, 2a and 3aPart 3: Number of participants with treatment-emergentParticipants With Adverse Events (AEs) (mCRPC, mHSPC and BRPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
    • AddedPart 1, 1a, 2a and Part 3: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedPart 4: PSA50 Response Rate (BRPC)Time frame: Up to 80 months
    • AddedPart 4: Duration of PSA50 Response (BRPC)Time frame: Up to 80 months
    • RemovedAll parts: Incidence of treatment emergent anti-drug antibodies (ADAs) to VIR-5500Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    Secondary outcomes 3 edited, 19 added, 7 removed
    What changed in the outcomes
    • EditedPart 2 and 4a4: Number of participants withParticipants With Adverse Events (AEs) (mCRPC, mHSPC and BRPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
    • EditedPart 1, 1a, 2a and 3a3: ObjectiveConfirmed PSA50 Response Rate (ORRmCRPC and mHSPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
    • EditedAll partsParts: Duration of responsePSA90 Response (DoRmCRPC, mHSPC and BRPC)Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months → Up to 80 months
    • AddedAll Parts: Confirmed PSA90 Response Rate (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedPart 1, 1a, 2a and 3: Objective Response Rate (ORR) (mCRPC and mHSPC)Time frame: Up to 80 months
    • AddedPart 1, 1a, 2, 2a, 3 and 4: Time to Response (TTR) (mCRPC and mHSPC)Time frame: Up to 80 months
    • AddedPart 1, 1a, 2, 2a, 3 and 4: Duration of Response (DOR) (mCRPC and mHSPC)Time frame: Up to 80 months
    • AddedPart 1, 1a, 2, 2a, 3 and 4: Radiographic Progression-Free Survival (PFS) (mCRPC and mHSPC)Time frame: Up to 80 months
    • AddedAll Parts: Time to PSA Progression (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedPart 1, 1a, 2, 2a, 3 and 4: Duration of PSA50 Response (mCRPC and mHSPC)Time frame: Up to 80 months
    • AddedPart 2 and 4: Rate for Undetectable PSA (mHSPC)Time frame: Up to 8 months
    • AddedPart 4: Rate for Undetectable PSA (BRPC)Time frame: Up to 24 months
    • AddedAll Parts: Pharmacokinetics (PK) of VIR-5500 in Plasma: Area Under the Concentration Time Curve (AUC) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 in Plasma: Maximum Observed Concentration (Cmax) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 in Plasma: Time to Reach Maximum Concentration (tmax) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 in Plasma: Trough Concentration (Ctrough) (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: Accumulation Ratio of VIR-5500 (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 Metabolite in plasma: AUC (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 Metabolite in Plasma: Cmax (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 Metabolite in plasma: tmax (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: PK of VIR-5500 metabolite in plasma: Ctrough (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • AddedAll Parts: Accumulation Ratio of VIR-5500 metabolite (mCRPC, mHSPC and BRPC)Time frame: Up to 80 months
    • RemovedPart 1 and 3a: PSA response rateTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    • RemovedAll parts: Progression Free Survival PFSTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    • RemovedAll parts: Assessment of PK parameters: CmaxTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    • RemovedAll parts: Assessment of PK parameters: AUCTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    • RemovedAll parts: Assessment of PK parameters: TmaxTime frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    • RemovedAll parts: Incidence of baseline anti-drug antibodies (ADAs) to VIR-5500Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    • RemovedAll parts: Incidence of treatment emergent anti-drug antibodies (ADAs) to VIR-5500Time frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months
    Interventions Added Drug: Docetaxel. Arm changed Part 4a: VIR-5500 in combination with an ARSI for Dose Expansion→Part 3b: VIR-5500 in Combination with Docetaxel ± ARSI for Dose Escalation. Arms added: Part 1a: VIR-5500 Monotherapy Japan Safety and PK Cohort·Part 2a: VIR-5500 Monotherapy China Safety and PK Expansion Cohort·Part 4a: VIR-5500 in Combination with an ARSI for Dose Expansion·Part 4b: VIR-5500 in Combination with Docetaxel ± ARSI for Dose Expansion
    Contact Study contact changed: c•••@vir.bio · •••5281→A•••@astellas.com · •••7704. See the current contact
    + 3 other changes: index terms, description and data sharing statement
  3. Oct 7, 2026
    9 sites added
    Show 9 added (5 Spain, 3 United States, 1 United Kingdom)
    • Duarte Cancer Center · Duarte, United States
    • Lennar Foundation Cancer Center · Irvine, United States
    • Chicago Cancer Center · Zion, United States
    • ES34007 · Barcelona, Spain
    • ES34010 · Logroño, Spain
    • ES34012 · Madrid, Spain
    • ES34013 · Málaga, Spain
    • ES34009 · Valencia, Spain
    • GB44003 · Leicester, United Kingdom
    + 1 other change: verification date

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

10

Registry details

Key details

Study ID
NCT05997615
Lead sponsor
Astellas Pharma Global Development, Inc.
Collaborators
Vir Biotechnology, Inc.
Responsible party
Sponsor
First posted
Aug 18, 2023
Start date
Aug 10, 2023
Primary completion
Sep 30, 2027 (estimated)
Completion
Jun 30, 2030 (estimated)
Last update
Oct 27, 2026

Study contacts

Astellas Pharma Global Development, Inc
Contact
Astellas.registration@astellas.com
800-888-7704
Medical Monitor
study director · Astellas Pharma Global Development, Inc.

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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