Trial to Assess the Safety and Antitumor Activity of GEN1057 in Malignant Solid Tumors

Key Inclusion Criteria:

• Advanced and/or metastatic malignant solid tumors, who have progressed on standardof care therapy for whom there is no available standard therapy likely to provideclinical benefit, or who are not candidates for available therapy, and for whomexperimental therapy with GEN1057 may be beneficial, in the opinion of theinvestigator.

• Be at least 18 (or the legal age of consent in the jurisdiction in which the trialis taking place) years of age.

• Have measurable disease according to RECIST v1.1.

• Have Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 to 1 atscreening and on C1D1 pretreatment. Note: If screening ECOG PS is assessed within 3days prior to C1D1, ECOG PS does not need to be reassessed at C1D1.

• Have a life expectancy of ≥3 months.

Key Exclusion Criteria:

• Has been exposed to any of the following prior therapies/treatments within thespecified timeframes:

• Treatment with an investigational anticancer agent within 28 days or forsystemic therapies within 5 half-lives of the drug, whichever is shorter, priorto trial treatment administration.

• Treatment with an investigational drug, including investigational vaccineswithin 28 days before the planned first dose of trial treatment.

• Prior treatment with live, attenuated vaccines within 28 days prior toinitiation of GEN1057. Examples of live vaccines include, but are not limitedto, the following: measles, mumps, rubella, varicella/zoster (chicken pox),yellow fever, rabies, Bacillus Calmette-Guérin, and typhoid vaccine. Seasonalinfluenza vaccines for injection are generally killed virus vaccines and areallowed; however, intranasal influenza vaccines (eg, FluMist®) are live,attenuated vaccines and are not allowed. Experimental and/or nonauthorizedsevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinations arenot allowed.

• Used an invasive investigational medical device within 28 days before theplanned first dose of trial treatment.

• Has clinically significant toxicities from previous anticancer therapies that havenot resolved to baseline levels or to grade 1, except for anorexia, hyperthyroidism,hypothyroidism, and peripheral neuropathy, which must have recovered to ≤ grade 2.There is no limitation for alopecia and hearing impairment from previous therapies.

• Has known, symptomatic brain metastases. Asymptomatic brain metastases are allowedprovided that they have been treated, have been stable for >28 days as documented byradiographic imaging, and do not require prolonged (>14 days) systemiccorticosteroid therapy.

• Has a past or current malignancy other than inclusion diagnosis.

Note: Other protocol-defined inclusion and exclusion criteria may apply.