Safety and Preliminary Efficacy Trial of BNT142 in Patients With CLDN6-positive Solid Tumors

Key Inclusion Criteria:

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

For Part 1 and 2:

- Histological or cytological documentation of a solid tumor that is metastatic or
unresectable via a pathology report.

- CLDN6-positive tumor sample as assessed by central laboratory testing using a
validated immunohistochemistry (IHC) assay in formalin-fixed paraffin-embedded
neoplastic tissues or alternatively from fresh tissue if archival tissue is
unavailable. If archival tissue samples from several points of time are available,
the most recent one is preferred.

- Measurable disease per RECIST 1.1 (measurable per RECIST 1.1 or evaluable per GCIG
criteria for ovarian tumors).

For Part 1 (Dose escalation):

- Patients with advanced/metastatic ovarian (including fallopian tube and peritoneal),
non-squamous NSCLC, endometrial, or testicular cancer, for whom there is no
available standard therapy likely to confer clinical benefit, or the patient is not
a candidate for such available therapy, or patients with not otherwise specified
(NOS) tumors (as confirmed by histological diagnosis), rare tumors (defined as those
occurring in <15 out of 100,000 people each year as per National Cancer Institute
[NCI] guidelines) and cancers of unknown primary, not included in the pre-defined
eligible tumor types. Patients must have received all available standard therapies,
including targeted therapies based on mutation status (per guidelines from the US
Food and Drug Administration [FDA], American Society of Clinical Oncology [ASCO],
European Society for Medical Oncology [ESMO] or local guidelines used at the site),
and failed at least first line standard of care therapy prior to enrollment.

Key Exclusion Criteria:

- Chemotherapy, or molecularly-targeted agents within 3 weeks or 5 half-lives
(whichever is longer) of the start of study treatment; immunotherapy/monoclonal
antibodies within 3 weeks of the start of study treatment; nitrosoureas,
antibody-drug conjugates, or radioactive isotopes within 6 weeks of the start of
study treatment.

- Radiotherapy in the last 6 weeks prior to the first dose of BNT142 (excluding brain
radiotherapy for which 3 weeks prior to the first dose of BNT142 is allowed).
Previously irradiated tumor lesions cannot be considered as target lesions or
non-target lesions in this study.

- Concurrent systemic (oral or intravenous [IV]) steroid therapy >10 mg prednisone
daily or its equivalent for an underlying condition apart from physiologic
corticosteroid replacement therapy.

- Major surgery within 4 weeks before the first dose of BNT142.

- Ongoing or active infection requiring IV treatment with anti-infective therapy that
has been administered less than 2 weeks prior to the first dose of BNT142.

- Prior treatment with a CLDN6 targeting therapy.

- Side effects of any prior therapy or procedures for any medical condition not
recovered to National Cancer Institute Common Terminology Criteria for Adverse
Events v.5 Grade ≤1, except for anorexia, fatigue, hyperthyroidism, hypothyroidism,
and peripheral neuropathy, which must have recovered to Grade ≤2. Alopecia of any
grade is allowed.

- Current evidence of new or growing brain or leptomeningeal metastases during
screening. Patients with known brain metastases may be eligible if they:

- Had radiotherapy, surgery or stereotactic surgery for the brain metastases;

- Have no neurological symptoms (excluding Grade ≤2 neuropathy);

- Have stable brain metastasis on the computer tomography (CT) or magnetic resonance
imaging (MRI) scan within 4 weeks before signing the informed consent form; and

- Are not undergoing acute corticosteroid therapy or steroid taper.

- Notes: Patients with central nervous system symptoms should undergo a CT scan or MRI
of the brain to exclude new or progressive brain metastases. Spinal bone metastases
are allowed, unless imminent fracture with cord compression is anticipated.

- Pregnant or breastfeeding or planning to get pregnant within 6 months of the last
dose of BNT142.