Study of Intravenous (IV) ABBV-637 Alone or in Combination With IV Docetaxel/Osimertinib to Assess Adverse Events and Change in Disease Activity in Adult Participants With Relapsed/Refractory (R/R) Solid Tumors

Cancer is a condition where cells in a specific part of body grow and reproduce uncontrollably. Non-Small Cell Lung Cancer (NSCLC) is a solid tumor, a disease in which cancer cells form in the tissues of the lung. The purpose of this study is to evaluate the safety and efficacy (how well the study drug works against the disease) of ABBV-637 alone or in combination with docetaxel/osimertinib in participants with solid tumors (NSCLC). Adverse events and change in disease activity will be assessed. ABBV-637 is an investigational drug being developed for the treatment of solid tumors. Study consists of 3 parts - monotherapy dose escalation (Part 1), combination dose escalation and expansion (Parts 2a and 2b) with docetaxel and combination dose escalation and expansion (Parts 3a and 3b) with osimertinib. Approximately 109 adult participants with relapsed/refractory (R/R) solid tumors will be enrolled in approximately 30 sites across the world. In Part 1, participants with solid tumors will receive intravenous (IV) ABBV-637 in 28-day cycles. In Part 2a and 2b, participants will receive IV ABBV-637 in combination with IV docetaxel in 28-day cycles. In Part 3a and 3b, participants will receive intravenous (IV) ABBV-637 in combination with daily oral tablets of osimertinib in 28-day cycle. There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. Treatment effects will be monitored by medical assessments, blood tests, side effect reporting, and questionnaires.