Phase 1 Study of CK-301 (Cosibelimab) as a Single Agent in Subjects With Advanced Cancers

Inclusion Criteria:

• Signed written informed consent.

• Male or female subjects aged greater than or equal to 18 years.

• For NSCLC: Histologically or cytologically confirmed diagnosis of unresectablerecurrent or metastatic non-small cell lung cancer.

• For CRC: Histologically confirmed diagnosis of recurrent or metastatic colorectalcancer assessed as microsatellite instability-high (MSI-H) or mismatch repairdeficient (dMMR).

• For EC: Histologically or cytologically confirmed advanced, recurrent or metastaticendometrial carcinoma.

• For cSCC: Histologically confirmed diagnosis of unresectable or metastatic cutaneoussquamous cell carcinoma not amenable to local therapy.

• For SCLC: Histologically or cytologically confirmed diagnosis of unresectable smallcell lung cancer.

• For MPM: Histologically or cytologically confirmed diagnosis of unresectablemalignant pleural or peritoneal mesothelioma.

• For HNSCC: Histologically or cytologically confirmed diagnosis of recurrent ormetastatic HNSCC (oral cavity, pharynx, larynx), stage III/IV and not amenable tolocal therapy with curative intent (surgery or radiation therapy with or withoutchemotherapy).

• For MEL: Histologically confirmed diagnosis of unresectable Stage III or metastaticmelanoma not amenable to local therapy (excluding uveal or ocular melanoma).

• For MCC: Histologically confirmed diagnosis of metastatic Merkel cell carcinoma notamenable to local therapy.

• For RCC: Histologically confirmed diagnosis of renal cell carcinoma (with clear cellcomponent) with advanced or metastatic disease that is not amenable to cure bysurgery or other means.

• For UC: Histologically or cytologically documented locally advanced or metastatictransitional cell carcinoma of the urothelium (including renal pelvis, ureters,urinary bladder, urethra) not amenable to cure by surgery or other means.

• For HL: Histologically confirmed primary diagnosis of classical Hodgkin's lymphoma.

• For B-cell NHL: Histologically confirmed diagnosis of non-Hodgkin lymphoma.

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 at trialentry and an estimated life expectancy of at least 3 months

• Must have at least one measurable lesion based on RECIST 1.1.

• Have provided a formalin fixed tumor tissue sample from a biopsy of a tumor lesioneither at the time of or after the diagnosis of metastatic disease has been made ANDfrom a site not previously irradiated.

• Adequate hematological, hepatic and renal function as defined in the protocol.

• Effective contraception for both male and female subjects if the risk of conceptionexists.

• Other protocol defined inclusion criteria could apply.

Exclusion Criteria:

• Prior therapy with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, anti-CTLA-4antibody, or any other antibody or drug specifically targeting T-cell co-stimulationor immune checkpoint pathways.

• Concurrent treatment with a non-permitted drug.

• History of severe hypersensitivity reactions to other monoclonal antibodies.

• Prior malignancy active within the previous 2 years except for locally curablecancers that have been apparently cured, such as basal or squamous cell skin cancer,superficial bladder cancer or carcinoma in situ of the cervix or breast, orlocalized prostate cancer.

• Chemotherapy, radioactive, biological cancer therapy, or tyrosine kinase inhibitor (TKI) therapy, within four weeks prior to the first dose of study drug, or who hasnot recovered to NCI CTCAE Grade 1 or better from the AEs due to cancer therapeuticsadministered more than four weeks earlier.

• Significant acute or chronic infections as defined in the protocol.

• Active or history of interstitial lung disease (ILD), or has had a history ofpneumonitis that has required oral or IV steroids.

• Active or suspected autoimmune disease or a documented history of autoimmunedisease.

• Known current drug or alcohol abuse.

• Underlying medical conditions that will make the administration of study drughazardous or obscure the interpretation of toxicity determination or adverse events.

• Use of other investigational therapy within 28 days before study drugadministration.

• Pregnant or breastfeeding.

• Uncontrolled or significant cardiovascular disease.

• Psychiatric illness or social situation that would preclude study compliance.

• Receipt of live, attenuated vaccine within 28 days prior to the first dose of studydrug.