A Study With ABBV-155 Alone and in Combination With Taxane Therapy in Adults With Relapsed and/or Refractory Solid Tumors

An open-label, dose-escalation (Part 1), dose-expansion (Part 2) study to assess the safety, pharmacokinetics (PK), and preliminary efficacy of ABBV-155 alone and in combination with paclitaxel or docetaxel. In Part 1 (dose escalation), participants will receive escalating doses of ABBV-155 monotherapy (Part 1a) or ABBV-155 in combination with paclitaxel or docetaxel (Part 1b). In Part 2 (dose expansion), participants will receive ABBV-155 monotherapy or in combination therapy. The ABBV-155 monotherapy cohort will enroll participants with relapsed or refractory (R/R) small cell lung cancer (SCLC) (Part 2a); the ABBV-155 plus a taxane (paclitaxel or docetaxel) combination cohort will enroll participants with R/R non-small cell lung cancer (NSCLC) and breast cancer (Part 2b).