A Study Comparing BMS-986504 in Combination With Nab-paclitaxel and Gemcitabine Versus Placebo in Combination With Nab-paclitaxel and Gemcitabine in Participants With Untreated Metastatic Pancreatic Ductal Adenocarcinoma With Homozygous MTAP Deletion (MountainTAP-30)

Inclusion Criteria: * Histologically or cytologically confirmed diagnosis of metastatic pancreatic ductal adenocarcinoma (PDAC). * Evidence of homozygous methylthioadenosine phosphorylase (MTAP) deletion or MTAP loss detected in tumor tissue. * Metastatic disease with at least 1 measurable lesion as per Response Evaluation Criteria in Solid Tumors version v1.1 (RECIST v1.1). * Participants must not have received any systemic anticancer treatments in the metastatic setting. * If clinically indicated and as per investigator discretion, participants may receive up to 1 cycle of Nab-paclitaxel/Gemcitabine (nab-p/gem) in the metastatic setting and must have not progressed or required discontinuation due to intolerable toxicity. * Initial cycle of nab-p/gem administered in the metastatic setting must have been completed prior to randomization. Exclusion Criteria: * Concurrent malignancy (present during screening) requiring treatment or history of prior malignancy active within 2 years prior to screening. * Other protocol-defined Inclusion/Exclusion criteria apply.