A Phase 3 interventional study of Aglatimagene besadenovec + valacyclovir and Placebo + valacyclovir in Prostate Cancer, sponsored by Candel Therapeutics, Inc.. Active, not recruiting at 73 sites in 2 countries. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-02.
Sponsored by Candel Therapeutics, Inc. · Phase 3, Interventional, and Treatment
The purpose of this study is to evaluate the effectiveness of ProstAtak® immunotherapy in combination with radiation therapy for patients with intermediate-high risk localized prostate cancer. ProstAtak kills tumor cells and stimulates a cancer vaccine effect. Killing tumor cells in an immune stimulatory environment induces the body's immune system to detect and destroy cancer cells. ProstAtak has shown synergy with radiation without added toxicity and lower than expected recurrence rates in previous clinical trials. The hypothesis is that ProstAtak can lead to improvement in the clinical outcome for patients with prostate cancer. Participants will be randomized to the ProstAtak or control arm at a 2:1 ratio. Both arms receive standard external beam radiation therapy. Short-term androgen deprivation therapy may be given but is not required.
6,370 studies on the registry are indexed under Prostatic Neoplasms; 1,400 are open to participants now.
This study's planned enrollment of 711 is above the median of 58 across 4,822 interventional studies indexed under Prostatic Neoplasms.
Browse Prostatic Neoplasms studies →Candel Therapeutics, Inc. is the lead sponsor of 13 studies on the registry; 2 are open to participants now.
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Localized prostate cancer meeting the NCCN criteria of Intermediate Risk or patients having only one NCCN high-risk feature
Exclusion Criteria include:
Aglatimagene besadenovec (CAN-2409) + valacyclovir + radiation therapy +/- ADT
Biological: Aglatimagene besadenovec + valacyclovir
Placebo + valacyclovir + radiation therapy +/- ADT
Biological: Placebo + valacyclovir
Patients will receive three courses of ProstAtak® each consisting of aglatimagene besadenovec injection + oral valacyclovir. AdV-tk injection will be delivered to the prostate via trans-rectal ultrasound guided injection as follows: 1. The first injection will be given at least 15 days and not more than 8 weeks before starting radiation. 2. The second injection will be 0-3 days before initiation of radiation therapy. 3. The third injection will be 15-22 days after the 2nd injection. The prodrug, valacyclovir, will be administered at a fixed dose for 14 days after each AdV-tk injection. Standard external beam radiation therapy will be delivered to the prostate. Short-term androgen deprivation therapy (maximum of 6 months) is optional but must be decided before enrollment to allow for stratification.
Also known as: AdV-tk, CAN-2409
Patients will receive three courses each consisting of placebo injection + oral valacyclovir. Placebo injection will be delivered to the prostate via trans-rectal ultrasound guided injection as follows: 1. The first injection will be given at least 15 days and not more than 8 weeks before starting radiation. 2. The second injection will be 0-3 days before initiation of radiation therapy. 3. The third injection will be 15-22 days after the 2nd injection. The prodrug, valacyclovir, will be administered at a fixed dose for 14 days after each placebo injection. Standard external beam radiation therapy will be delivered to the prostate. Short-term androgen deprivation therapy (maximum of 6 months) is optional but must be decided before enrollment to allow for stratification.
Disease free survival defined as the time from randomization until the date of the first failure event will be compared for the ProstAtak® arm versus the placebo control arm. The analyses will be based on the intent to treat population.
Time frame: Assessed at each visit every 6 months through year 5 until event occurs.
Prostate cancer specific survival and overall survival will be compared for the ProstAtak® arm versus the placebo control arm.
Time frame: Assessed at each visit every 6 months through year 5 after which long-term follow up of general health status will continue yearly.
PSA nadir will be compared for the ProstAtak® arm versus the placebo control arm.
Time frame: Assessed at each visit every 6 months through year 5.
Patient reported Health Related Quality of Life outcomes will be collected using the Expanded Prostate Cancer Index Composite (EPIC-26) questionnaire. The change in QOL over time will be compared for the ProstAtak® arm versus the placebo control arm.
Time frame: Assessed at baseline and at 3, 6, 12, 18 and 24 months after completion of radiation.
The safety profile will be characterized by collection of adverse event information and laboratory values during the treatment phase (until the completion of radiation). Data on late effects will be collected after radiation completion.
Time frame: Assessed at each visit and continuously throughout the study.
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 ↗
This study is active, not recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Candel Therapeutics, Inc.