Study of Safety and Antitumor Activity of GEN1056 in Participants With Advanced Solid Tumors

Key Inclusion Criteria:

• Subjects with histologically or cytologically confirmed non-CNS advanced ormetastatic solid tumors which has progressed despite standard therapy, or subjectswho are intolerant of standard therapy, or for which no standard therapy exists, andfor whom, in the opinion of the investigator, experimental therapy with GEN1056 maybe beneficial

• Have personally (or in countries where permitted, their legally acceptablerepresentative) signed an Informed Consent Form (ICF)

• Are at least 18 years of age.

• Have measurable disease according to the RECIST v1.1 criteria.

• Have an ECOG PS of 0 to 1 at screening and on C1D1 pre-treatment.

• Have acceptable laboratory test results during the screening period.

• Must provide an archival (FFPE) tumor tissue sample or newly obtained core orexcisional biopsy of a tumor lesion not previously irradiated.

• A female subject with reproductive potential must agree to use adequatecontraception during the trial, and for 4 months after receiving the last dose oftrial drug GEN1056.

Key Exclusion Criteria:

• Subject is considered a poor medical risk due to a serious, uncontrolledinter-current illness

• Prior therapy with a checkpoint inhibitor agent or with an agent directed to anotherstimulatory or co-inhibitory T-cell receptor.

• Prior exposure to any of the following prior therapies within the specifiedtimeframes:

1. Systemic cytotoxic chemotherapy or antineoplastic biological therapy within 28days or at least 5 elimination half-lives of the drug (whichever is shorter) ofthe first dose of trial treatment

2. Radiotherapy within 21 days of start of trial treatment. Note: palliativeradiotherapy be allowed.

3. Prior treatment with live, attenuated vaccines within 28 days prior toinitiation of GEN1056

• Known active CNS metastases and/or carcinomatous meningitis, or spinal cordcompression.

• Positive for Human Immunodeficiency Virus (HIV), Hepatitis B (Hepatitis B SurfaceAntigen (HBsAg), HBV DNA), or Hepatitis C infection (Hepatitis C Virus RibonucleicAcid (HCV RNA), HCV antibodies).

• An active, known, or suspected autoimmune disease, requiring systemic steroid.

• A condition requiring systemic treatment with either corticosteroids (>10 mg dailyprednisone equivalent) or other immunosuppressive medications within 14 days offirst treatment.

• History of non-infectious pneumonitis/interstitial lung disease that requiredsteroids or has current pneumonitis/interstitial lung disease requiring treatmentwith steroids.

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