A Study of Modakafusp Alfa (TAK-573) Given by Itself and Together With Pembrolizumab in Adults With Advanced or Metastatic Solid Tumors

The drug being tested in this study is called modakafusp alfa (TAK-573). Modakafusp alfa is being tested to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and antitumor activity as single agent (SA) or in combination with pembrolizumab in participants with locally advanced or metastatic solid tumors. The study will consist of 2 phases: Phase 1b dose escalation and a Phase 2 dose expansion. The study will enroll approximately 114 participants (approximately 30 participants in Phase 1b dose escalation phase; 3-9 participants in safety-lead in and 25 participants for each expansion cohort (3 cohorts) of Phase 2. The dose escalation phase will enroll participants with solid tumors. The dose escalation phase is to evaluate SA recommended phase 2 dose (RP2D). The dose expansion phase in combination with pembrolizumab will be initiated with a safety lead-in phase once the SA RP2D is determined for modakafusp alfa. The dose expansion will include participants with one of following 3 disease indications: I. Unresectable/metastatic cutaneous melanoma with primary resistance to no more than 2 prior lines of anti-disease programmed cell death protein 1 (PD1) containing treatments in the metastatic setting. II. Unresectable/metastatic cutaneous melanoma with acquired resistance to no more than 2 prior lines of anti-PD1 containing treatments in the metastatic setting. III. Unresectable/metastatic cutaneous melanoma naïve to prior anti-PD1 containing treatments in the metastatic setting. This multi-center trial will be conducted in the United States and Australia. Participants with demonstrated clinical benefit may continue treatment beyond 1 year for Phase 1b and 2 years for Phase 2 if approved by the sponsor. The overall time to participate in this study is 55 months. All participants will make an end of treatment (EOT) visit 30 days after receiving their last dose of study drug or before the start of subsequent systemic anticancer therapy, whichever occurs first for a safety follow up assessment.