Early cancer drug trial halted after just 3 patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Pre-screening: * Age ≥ 18 years. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 -1. * Participants with histologically or cytologically documented malignant solid tumor diseases expressing claudin-6 (CLDN6) including but not limited to NSCLC, EOC, testicular germ cell cancer, uterine endometrial cancer, or triple negative breast cancer, and the cancer is at least either locally advanced or metastatic at pre-screening. * Participant has provided informed consent prior to initiation of any study specific activities/procedures. Main study: * Age ≥ 18 years. * Participant has provided informed consent prior to initiation of any study specific activities/procedures. * ECOG performance status of 0 to 1. * Participants with histologically or cytologically documented malignant solid tumor diseases expressing CLDN6 including but not limited to NSCLC, EOC, testicular germ cell cancer, uterine endometrial cancer, or triple negative breast cancer, that is metastatic or unresectable at screening time point. Participants should have exhausted available SOC systemic therapy or should not be candidates for such available therapy. * For participants enrolling in cohort 3 or higher dose cohort, available positive test result for CLDN6 expression resulting from testing of an available archival tissue sample in pre-screening or obtained from biopsy in a screening procedure. For participants enrolling in cohorts 1, 1a, or 2 during dose escalation, consent to provide archival or fresh tumor tissue slides for immunohistochemistry (IHC) assessment is sufficient and the enrolment is not dependent on availability of the CLDN6 expression test result. * For dose expansion cohorts: Participants with at least 1 measurable lesion ≥ 10mm which has not undergone biopsy within 3 months of screening scan. This lesion cannot be biopsied at any time during the study. * Life expectancy \> 3 months. * Adequate organ functions. Exclusion Criteria: Main study: * Positive test for human immunodeficiency virus, hepatitis B or hepatitis C. * History of other malignancy within the past 2 years. * Participant with symptoms and/or clinical signs and/or radiographic signs that indicate an acute and/or uncontrolled active systemic infection with 1 week prior to administration of a first dose of study treatment * Evidence of new or growing central nervous system metastases, leptomeningeal disease, or spinal cord compression. Participants with known brain metastases may be eligible if they completed radiotherapy, surgery or stereotactic surgery for the brain metastases and do not present with neurological symptoms and/or have stable disease assessed by imaging within 4 weeks of signing consent to this study and not requiring acute corticosteroid therapy or steroid taper. * Currently receiving treatment in another investigational device or drug study, or less than 4 weeks since ending treatment on another investigational device or drug study(ies). Other investigational procedures while participating in this study are excluded. * Anticancer therapies including radiotherapy, chemotherapy or molecularly targeted treatments or tyrosine kinase inhibitors within 2 weeks or 5 half-lives (whichever is longer) of administration of a first dose of study treatment; immunotherapies/monoclonal antibodies within 3 weeks of administration of a first dose of study treatment. * Has had a major surgery within 4 weeks of administration of a first dose of study treatment (excluded: biopsies and central venous catheter insertion). * Autoimmune disorders requiring chronic systemic steroid therapy or any other form of immunosuppressive therapy while on study, (e.g., ulcerative colitis, Crohn's disease). Recent or current use of inhaled steroids or physiological substitution in case of adrenal insufficiency is not exclusionary. * Female participants who are of childbearing potential unwilling to use protocol-specified method of contraception, who are breastfeeding and/or planning to become pregnant. * Male participants who have a female partner of childbearing potential who are unwilling to practice sexual abstinence or use protocol-specified contraception and/or who are unwilling to abstain from donating sperm. * Participant has known sensitivity to any of the products or components to be administered during dosing. * Participant likely to not be available to complete all protocol-required study visits or procedures, and/or to comply with all required study procedures (e.g., Clinical Outcome Assessments) to the best of the participant and investigator's knowledge. * History or evidence of any other clinically significant disorder, condition or disease (with the exception of those outlined above) that, in the opinion of the investigator or Amgen physician, if consulted, would pose a risk to participant safety or interfere with the study evaluation, procedures or completion.