Study to Evaluate Adverse Events and Efficacy of Intravenous (IV) Telisotuzumab Adizutecan in Combination With a PD-1 Immune Checkpoint Inhibitor in Adult Participants With Advanced or Metastatic Non-Squamous NSCLC With No Prior Treatment for Advanced Disease, and No Actionable Genomic Alterations

Non small cell lung carcinoma (NSCLC) is the most frequently occurring histologic subtype of lung cancer and is the leading cause of cancer-related deaths worldwide. The purpose of this study is to assess adverse events and change in disease activity when Telisotuzumab Adizutecan (ABBV-400) is given in combination with a programmed cell death receptor 1 (PD1) immune checkpoint inhibitor to adult participants to treat NSCLC.

Telisotuzumab Adizutecan (ABBV-400) and budigalimab are investigational drugs being developed for the treatment of NSCLC. This study will be divided into two stages, with the first stage treating participants with several doses of telisotuzumab adizutecan in combination with budigalimab within the dose escalation regimen until the dose reached is tolerable and expected to be efficacious. In Stage 2 there will be 3 treatment groups. Two groups will receive pembrolizumab with different optimized doses of telisotuzumab adizutecan (to allow for the best dose to be studied in the future). One group will receive the standard of care (SOC) - pembrolizumab, pemetrexed, and investigator's choice of carboplatin or cisplatin, followed by pembrolizumab and pemetrexed. Approximately 252 adult participants with NSCLC will be enrolled in the study in 132 sites worldwide.

In the dose escalation stage participants will be treated with increasing intravenous (IV) doses of Telisotuzumab Adizutecan in combination with budigalimab until the dose of Telisotuzumab Adizutecan reached is tolerable and expected to be efficacious. In the dose optimization stage participants will be receive IV optimized doses of Telisotuzumab Adizutecan in combination with IV pembrolizumab, or IV SOC - pembrolizumab, pemetrexed, and investigator's choice of carboplatin or cisplatin, followed by pembrolizumab and pemetrexed. The study will run for a duration of approximately 33 months.

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 an approved institution (hospital or clinic). The effect of the treatment will be frequently checked by medical assessments, blood tests, questionnaires and side effects.