IDEAYA Biosciences, Inc. announced updated clinical results from the ongoing investigator-sponsored Phase 2 trial of darovasertib, a first-in-class oral, small molecular inhibitor of protein kinase C (PKC), as neoadjuvant/adjuvant treatment in uveal melanoma (UM) and clinical update for Phase 2 company-sponsored neoadjuvant UM study. The clinical data from the ongoing investigator-sponsored Phase 2 trial were included in an oral presentation at the American Society of Clinical Oncology (ASCO) 2024 Annual Meeting. Anthony Joshua, MBBS, PhD, FRACP, Head Department of Medical Oncology, Kinghorn Cancer Centre, St.

Vincent's Hospital in Sydney, and the lead principal investigator of the Phase 2 study, presented clinical results from the Phase 2 Neoadjuvant /Adjuvant trial of Darovasertib in Ocular Melanoma (NADOM) at ASCO. Fifteen patients planned for enucleation with localized?UM were treated with darovasertib 300mg twice daily. An initial safety cohort of three patients were treated for one month, and the remaining 12 patients were treated in an expansion cohort for up to six months as neoadjuvant treatment prior to their primary intervention (enucleation, plaque brachytherapy or external beam radiotherapy (EBRT)) across three Australian centers.

As of the database lock on May 14, 2024, 13 patients had completed neoadjuvant treatment, 11 patients received adjuvant darovasertib after primary treatment of their UM, with five patients completing the planned six months of therapy. As of May 14, 2024, 75% (9 out of 12 enucleation patients) had confirmed Eye Saved (i.e., converted to plaque brachytherapy or EBRT) and approximately 67% (8 out of 12 enucleation patients) observed greater than 30% tumor shrinkage (maximum volume change) after 6 months. Median tumor shrinkage (maximum volume change) in 12 enucleation patients was approximately 47% after 6 months.

The darovasertib monotherapy neoadjuvant treatment had a manageable adverse event (AE) profile with no drug-related serious adverse events observed. Drug-related AEs were predominantly Grade 1 or Grade 2 and 20% of patients reported at least one drug-related Grade 3 adverse event. The Company is targeting a Type C meeting with the FDA to discuss a potential registrational trial for darovasertib in the neoadjuvant UM setting and a clinical efficacy update from its Phase 2 company-sponsored darovasertib neoadjuvant UM trial in H2 2024.

As of May 24, 2024 cut-off date, the Phase 2 company-sponsored darovasertib neoadjuvant UM trial has activated over 14 sites globally and enrolled over 40 patients. As of the cut-off date, 8 patients (6 enucleation and 2 plaque eligible) have been on darovasertib treatment for 4-months or more and observed median tumor shrinkage (maximum height/base/volume change) of approximately 40%/25%/72% and the majority of the 6 enucleation patients had reported Eye Saved (i.e., converted to plaque brachytherapy or EBRT eligible). In the 8 patients with 4-months or more of darovasertib treatment as of May 24, 2024, darovasertib had a manageable AE profile with no drug-related serious adverse events observed, and drug-related AEs were predominantly Grade 1 or Grade 2 and approximately 13% of patients reported at least one drug-related Grade 3 AE.

The darovasertib program has ongoing enrollment of a potential registrational Phase 2/3 trial in first-line HLA-A2-negative metastatic UM (MUM), and Phase 2 trials in HLA-A2 positive MUM and neoadjuvant and adjuvant UM. Darovasertib received FDA Fast Track designation in MUM and FDA Orphan Drug designation for the treatment of Uveal Melanoma, including MUM. The company project the global annual incidence of primary uveal melanoma is approximately 8,000 to 10,000 patients, with the majority of patients in the U.S. and Europe.