This is a multicenter, open-label, first-in-human, Phase 1/2 study to evaluate the safety and preliminary efficacy of EGL-001 in patients with selected advanced or metastatic solid tumors that have developed secondary resistance to anti-PD(L)-1 treatment, as monotherapy or in combination with anti-PD(L)-1 treatment.

The study consists of a Part 1 (Phase 1) open-label, dose escalation of EGL-001 administered as a single agent (monotherapy arm) and in combination with an anti-PD(L)-1 treatment (combination therapy arm), followed by a Part 2 (Phase 2) open-label, dose expansion of EGL-001 administered at the RP2D in patients with recurrent and/or metastatic solid tumors as monotherapy and/or combination therapy with anti-PD(L)-1.

Patients will be dosed with EGL-001 once every week until disease progression, unacceptable toxicity, or patient withdrawal from the study for any reason, or for a maximum of 1 year, whichever occurs first.

The duration of the study will depend on the determination of the RP2D and completion of Part 2.