An 81-year-old male diagnosed with unresectable epithelioid malignant mesothelioma...NGS demonstrated homozygous MTAP deletion and a PIK3CA mutation….MRTX1719 was resumed at 100 mg q.d. p.o. without recurrence of diarrhea. The first on-study disease assessment at cycle 2 day 20 demonstrated stable disease with a 13% reduction of target lesions. The subsequent disease assessment at cycle 4 day 20 achieved RECIST-defined partial response with a 30.7% reduction of target lesions, and despite dose interruption, disease assessment on cycle 6 day 9 showed ongoing confirmed partial response...