A Phase 1, Multi-center, Open Label First-in-Human Study With ABBV-CLS-579 Alone and in Combination With Anti-PD-1 in Subjects With Locally Advanced or Metastatic Tumors

The purpose of this study is to see how safe and effective ABBV-CLS-579 is when used alone or in combination with programmed cell death protein-1 (PD-1) inhibitors in treating solid cancers.

ABBV-CLS-579 is an investigational drug being developed for the treatment of solid tumors. The study has two arms - Monotherapy and Combination Therapy. In the monotherapy arm, participants will receive ABBV-CLS-579 alone, in increasing doses. In the combination therapy arm, escalating doses of ABBV-CLS-579 will be given in combination with a PD-1 inhibitor. Adult participants with a diagnosis of some solid tumors for which no effective standard therapy exists, or has failed will be enrolled.

Participants will receive oral ABBV-CLS-579 capsule alone or in combination with intravenous (IV) PD-1 inhibitor. Participants will receive study drug treatment until disease progresses or discontinued.

There may be a higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the course of the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects, and completing questionnaires.