A Phase 1 interventional study of CBX-663 in Advanced Solid Tumors, Recurrent or Progressive Glioblastoma and Relapse or Refractory Myeloid Malignancies, sponsored by Crossbow Therapeutics, Inc.. Recruiting at 4 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-21.
Sponsored by Crossbow Therapeutics, Inc. · Phase 1, Interventional, and Treatment
This is a Phase 1, open-label, dose-escalation study of CBX-663 in participants with R/R AML, MDS or CMML (Cohort A), advanced solid tumors (Cohort B), or recurrent or progressive GBM (Cohort C) (collectively called 'indication cohorts'). Participants aged ≥18 years are planned to be enrolled. CBX-663 will initially be investigated on a fixed dosing schedule. CBX-663 will be administered intravenously (IV) on Cycle 1 Day 1 (C1D1) and then once weekly (QW) in 21-day cycles. Participants will continue treatment with CBX-663 until unacceptable toxicity, progressive disease, withdrawal of consent, or lack of clinical benefit.
Crossbow Therapeutics, Inc. is the lead sponsor of 2 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Inclusion Criteria:
Cohort A (R/R AML, MDS or CMML) Specific Inclusion Criteria:
R/R MDS as per WHO 2022. Participants must have peripheral or bone marrow blasts \<20%, and must have exhausted locally available treatments, including treatments for actionable mutations.
a. For High-Risk MDS participants, participants must be resistant to or to at least 4 cycles of hypomethylating agents or have progressed or are intolerant to such agents.
Any prior treatment-related toxicities resolved to Grade ≤1 prior to enrollment, with the exception of Grade ≤2 alopecia.
Cohort B (Solid Tumor) Specific Inclusion Criteria:
(as defined by version 1.1).
Prior Therapy
Radiation Therapy: At least 60 days from prior total body irradiation, craniospinal radiation and/or ≥50% radiation of the pelvis, or at least 14 days from local palliative radiation therapy (small port).
Cohort C (Recurrent/Progressive GBM) Specific Inclusion Criteria:
Any prior treatment-related toxicities resolved to ≤Grade 1 prior to enrollment, with the exception of ≤Grade 2 alopecia and ≤Grade 2 fatigue.
Inclusion Criteria for All Participants:
Adequate liver function defined as:
Exclusion Criteria:
Cohort C (Recurrent/Progressive GBM) Specific Exclusion Criteria:
mass effect or midline shift.
Exclusion Criteria for All Participants:
Active central nervous system (CNS) disease. Participants with prior CNS history can be enrolled if the participant has a negative lumbar puncture following completion of intrathecal chemotherapy.
Cardiac Disease:
Any commercially available or investigational anti-leukemic or anti-cancer therapy other than CBX 663, with the following exceptions:
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.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
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.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
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.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
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.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Measurable disease
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Leptomeningeal disease
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GVHD (graft-versus-host disease)
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Intravenous (I.V.) CBX-663
Drug: CBX-663
Intravenous (I.V.) CBX-663
Recommended Phase 2 Dose (RP2D)
To determine the RP2D.
Time frame: Until the end of study (approximately 24 months)
To determine safety and tolerability of CBX-663; Dose Limiting Toxicities (DLTs), Treatment-Emergent Adverse Events (TEAEs) and Treatment-Related Adverse Events (TRAEs).
Frequency and type of dose-limiting toxicities (DLT), Frequency, duration, and severity of treatment-emergent adverse events (TEAEs), treatment-related AEs (TRAEs), and serious adverse events (SAEs), Frequency and severity of cytokine release syndrome (CRS) adverse events (AEs), Withdrawal from the study, drug discontinuations, drug interruptions, or dose reductions due to adverse events Incidence/shifts of clinical laboratory abnormalities
Time frame: From enrollment through 30 days following end of treatment.
To assess the PK of CBX-663: AUC0-t
Area under the plasma concentration-time curve from time 0 to time of last measurable concentration (AUC0-t) of CBX-663 and relevant metabolites.
Time frame: Approximately 1 year.
To assess the PK of CBX-663: Cmax
Maximum plasma concentration (Cmax) of CBX-663 and relevant metabolites.
Time frame: Approximately 1 year.
To assess the PK of CBX-663: Tmax
Time to observed maximum plasma concentration of CBX-663 and relevant metabolites
Time frame: Approximately 1 year.
To assess the PK of CBX-663: Ctau
CBX-663 drug concentration at the end of the dosing interval.
Time frame: Approximately 1 year.
To assess the PK of CBX-663: T½
Terminal elimination half-life of CBX-663.
Time frame: Approximately 1 year.
To assess the PK of CBX-663: Degree of accumulation
Degree of CBX-663 accumulation in the blood stream and body.
Time frame: Approximately 1 year.
To assess the preliminary anti-leukemic activity of CBX-663 in participants with R/R AML (Cohort A):
Objective response rate (ORR), complete response (CR), CR with partial hematologic recovery (CRh), CR with incomplete hematologic recovery (CRi) (Dohner, 2022) CR rate (CR+CRh) CRc Rate (CR+ CRh + CRi)
Time frame: From enrollment through 30 days following end of treatment
To assess the preliminary anti-leukemic activity of CBX-663 in participants with R/R CMML (Cohort A)
Response criteria for CMML: evaluated per IWG 2015 (Savona, 2015) in adults with endpoints including CR, PR, complete cytogenetic remission, marrow response and clinical benefit as appropriate
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in participants with R/R MDS (Cohort A):
Best Overall Response (BOR) as defined by MDS/MPN International Working Group (IWG) 2023 (Zeidan, 2023) for Higher-Risk MDS and IWG 2018 (Platzbecker, 2019) for Lower-Risk MDS
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in participants in Cohort A: Duration of Response (DoR)
To assess the duration of response (DoR) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in participants in Cohort A: Time to Response (TTR)
To assess the time to response (TTR) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in participants with R/R AML, MDS or CMML (Cohort A): CRminimal residual disease (MRD)- rate for participants with CRc.
To assess the CRminimal residual disease (MRD)- rate for participants with CRc of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in Cohort A: Hematologic Improvement (HI)
HI defined as: * Not meeting criteria for CR (or CR equivalent) or CRuni or CRL * HIerythroid (HI-E) * HIplatelets (HI-P) * HIneutrophils (HI-N)
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in Cohort A: Transfusion Independence
Transfusion independence defined as any transfusion-free period lasting for at least 56 consecutive days, during which the participant is either on CBX-663 therapy or after cessation of CBX-663 therapy but prior to the start of new therapy.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in Cohort A: Transfusion burden reduction
To assess the transfusion burden reduction of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in Cohort A: Rate of leukemic transformation
To assess the rate of leukemic transformation of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in Cohort A: Event free survival (EFS)
To assess the Event free survival (EFS) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-leukemic activity of CBX-663 in Cohort A: Overall Survival (OS)
To assess the Overall Survival (OS) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort B based on Investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria: Overall Response Rate (ORR)
To assess overall response rate (ORR) of CBX-663.
Time frame: From enrollment through 30 days following the end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort B based on Investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria: Duration of Response (DoR)
To assess duration of response of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort B based on Investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria: Time to Response (TTR)
To assess time to response (TTR) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort B based on Investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria: Disease Control Rate (DCR)
To assess disease control rate (DCR) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort B based on Investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria: Progression Free Survival (PFS)
To assess progression free survival (PFS) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort B based on Investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria: Overall Survival (OS)
To assess overall survival (OS) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in participants with recurrent/progressive GBM (Cohort C): Overall Response Rate (ORR)
To assess the overall response rate (ORR) per Response Assessment in Neuro-Oncology (RANO) Criteria 2.0 (Wen 2023) and iRANO
Time frame: From enrollment through 30 days following the end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Duration of Response (DoR)
To assess duration of response (DoR) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Time to Response (TTR)
To assess time to response (TTR) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Disease Control Rate (DCR)
To assess disease control rate of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Progression Free Survival (PFS)
To assess progression free survival (PFS) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Overall Survival (OS)
To assess overall survival (OS) of CBX-663.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Changes in Corticosteroid Use
To assess changes in corticosteroid use in participants with GBM.
Time frame: From enrollment through 30 days following end of treatment.
To assess the preliminary anti-tumor activity of CBX-663 in Cohort C: Changes in neurologic function as assessed by the Neurological Assessment in Neuro-Oncology scale
To assess changes in neurologic function as assessed by the Neurological Assessment in Neuro-Oncology scale in participants with GBM.
Time frame: From enrollment through 30 days following end of treatment.
To assess the immunogenicity of CBX-663.
Incidence and severity of anti-drug antibodies (ADAs)
Time frame: From enrollment through 30 days following the end of treatment.
Plan to share: Yes — It is anticipated that the results of this study may be presented at scientific meetings and/or published in a peer reviewed scientific or medical journal. A Publications Committee, comprised of Investigators participating in the study and representatives from Crossbow as appropriate, will be formed to oversee any publication or presentation of the study results, which will reflect the experience of all participating study centers. All such publications and presentations must be approved in advance by Crossbow, in its sole discretion. Subsequently, individual Investigators may publish results from the study in compliance with their agreement with the Sponsor.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: One year after publication.
Access criteria: Requests to be reviewed on an individual basis by Crossbow Therapeutics, Inc.
No publications or documents are linked to this record.
Started Aug 2026 (actual). Primary completion is estimated for Jan 2028, 17 months after the start.
How these figures are worked out, and which studies are left out of them.
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 ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
No contact was published for this record. The registry link below has the sponsor’s details.
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Crossbow Therapeutics, Inc.