A Phase 1 interventional study of XmAb541 in Ovarian Cancer, Endometrial Cancer and Germ Cell Tumor, sponsored by Xencor, Inc.. Recruiting at 27 sites in 6 countries. Open to participants aged 15 Years and older. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by Xencor, Inc. · Phase 1, Interventional, and Treatment
The primary purpose of this study is to determine whether the investigational drug XmAb541 is safe and well tolerated, and to determine an optimal and safe dose(s) for further study. The study will also evaluate the effect of XmAb541 on tumor outcomes.
3,381 studies on the registry are indexed under Ovarian Neoplasms; 790 are open to participants now.
This study's planned enrollment of 282 is above the median of 54 across 2,548 interventional studies indexed under Ovarian Neoplasms.
Browse Ovarian Neoplasms studies →Xencor, Inc. is the lead sponsor of 30 studies on the registry; 7 are open to participants now.
Of its 15 completed or terminated interventional studies of FDA-regulated products, 2 (13%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
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.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
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.
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.
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 weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
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.
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.
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.
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.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
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.
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.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
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.
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.
Intravenous or Subcutaneous administration
Biological: XmAb541
Monoclonal bispecific antibody
Incidence of adverse events
Time frame: Day 1 to 2 years
Incidence of dose-limiting toxicities (DLTs)
Time frame: Day 1 to Day 28
Incidence of cytokine release syndrome (CRS)
Time frame: Day 1 to Day 28
Measurement of Cmax
Peak plasma concentration
Time frame: Day 1 to 2 years
Measurement of area under curve (AUC)
Area under the plasma concentration versus time curve
Time frame: Day 1 to 1.4 years
Measurement of Ctrough
Plasma concentration before next dose
Time frame: Day 1 to 2 years
Objective Response Rate
Objective Response Rate by RECIST 1.1 assessment of CT/MRI imaging
Time frame: Day 1 to 2 years
Duration of Response
Duration of Response Objective Response Rate by RECIST 1.1 assessment of CT/MRI imaging
Time frame: Day 1 to 2 years
Changes in Circulating Tumor DNA (ctDNA)
Maximum variant frequency or mean/median variant frequency
Time frame: Day 1 to 4 months
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 ↗
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