IDEAYA Biosciences, Inc. announced that it has dosed its first patient in the IDEAYA-sponsored Phase 1 trial evaluating the combination of IDE397, IDEAYA's investigational MAT2A inhibitor, and Trodelvy® (sacituzumab govitecan-hziy), Gilead's Trop-2 directed ADC, in patients with MTAP-deletion bladder cancer. The IDE397 and Trodelvy combination Phase 1 trial is included as an arm of an ongoing IDEAYA-sponsored clinical trial (NCT04794699), which includes a Phase 2 expansion arm of IDE397 monotherapy in MTAP-deletion solid tumors. The global Phase 1 clinical trial will evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of IDE397 in combination with Trodelvy.

IDE397 is a potent and selective small molecule inhibitor targeting methionine adenosyltransferase 2 alpha (MAT2A) in patients having solid tumors with methylthioadenosine phosphorylase (MTAP) deletion. Gilead's Trodelvy is currently approved in nearly 50 countries for 2L metastatic triple-negative breast cancer and in more than 30 countries for pre-treated HR+/HER2- metastatic breast cancer (mBC). In the U.S., Trodelvy has an accelerated approval for the treatment of patients with locally advanced or metastatic urothelial cancer (mUC) who have previously received a platinum-containing chemotherapy and anti-PD-(L)1 therapy.

Pursuant to the clinical study collaboration and supply agreement, IDEAYA and Gilead retain the commercial rights to its respective compounds, including with respect to use as a monotherapy or combination agent. IDEAYA is the study sponsor and Gilead will provide the supply of Trodelvy to IDEAYA. There is separately an Amgen-sponsored Phase 1/2 trial of IDE397 and AMG 193 combination in MTAP-Deletion NSCLC (NCT05975073) for which the companies intend to develop a joint publication strategy in 2024.

The Company is targeting a clinical data update for the IDE397 Phase 2 monotherapy expansion dose in MTAP-deletion bladder and lung cancer in over 15 evaluable patients in the second half of 2024. The Company is also advancing multiple preclinical stage MTAP-deletion programs to enable wholly-owned combinations with IDE397, including a program targeting a Development Candidate nomination in the second half of 2024. IDE397 monotherapy or in combination with Trodelvy has not been approved by any regulatory agency and the efficacy and safety of this combination has not been established.