Phase 1a/1b Study of Aplitabart (IGM-8444) Alone or in Combination in Participants with Relapsed, Refractory, or Newly Diagnosed Cancers

Key Inclusion Criteria:

* Age ≥ 18 years at time of signing ICF
* ECOG Performance Status of 0 or 1
* Histologic documentation of incurable, locally advanced or metastatic tumor of the type being evaluated in individual cohorts.
* Adequate hepatic and renal function and adequate bone marrow reserve function.
* For combination cohorts, participants must be eligible to receive the chemotherapy or targeted agent.
* Ph1a only: No more than three prior therapeutic regimens.
* Ph1b only: Must be FOLFIRI naïve participants and must have received only 1 prior therapeutic regimen administered for the treatment of cancer in the advanced/metastatic setting - OR - FOLFIRI naïve participants that only received adjuvant therapy who progressed within six months after completing adjuvant therapy, and are confirmed to have locally advanced/metastatic disease

Key Exclusion Criteria:

* Inability to comply with study and follow-up procedures.
* Prior DR5 agonist therapy.
* Concomitant use of agents well-known to cause liver toxicity.
* Concomitant use of anti-cancer agents
* Palliative radiation to bone metastases within 2 weeks prior to Day 1.
* Major surgical procedure within 4 weeks prior to Day 1.
* Untreated or active central nervous system (CNS) metastases (progressing or requiring anticonvulsants or corticosteroids for symptomatic control). Participants with a history of treated CNS metastases are eligible.
* Prior use of any chemotherapeutic agent or small molecule inhibitors (SMI) within 2 weeks or 5 half-lives, prior to the first dose of study treatment
* Treatment with a monoclonal antibody, or any other anticancer agent (including biologic, experimental, or hormonal therapy) investigational or otherwise, that is not chemotherapy or a SMI, within 4 weeks or five half-lives prior to first dose of study treatment.
* Ph1b: Participants who have previously received FOLFIRI treatment in the adjuvant, advanced, or metastatic disease setting