ASCO 2026: Darovasertib Raises the Bar in Metastatic Uveal Melanoma

OptimUM-02 Trial Shows Darovasertib Plus Xalkori Improves PFS in UM

Primary results from the global, multi-centre, open-label Phase II/III OptimUM-02 clinical trial were presented at the American Society of Clinical Oncology (ASCO) Annual Meeting 2026. The trial evaluated Ideaya Biosciences’ darovasertib in combination with Pfizer’s Xalkori (crizotinib) as first-line therapy for HLA A*02:01-negative metastatic uveal melanoma. The combination met its primary efficacy endpoint, significantly improving median progression-free survival (PFS) to 6.9 months compared to 3.1 months for investigator’s choice therapy (HR, 0.42; p<0.0001). This represents a 58% reduction in the risk of progression or death. The combination also delivered a substantially higher objective response rate (37.1% vs 5.8%) and an improved disease control rate (73.3% vs 31.1%).

• The darovasertib plus Xalkori combination demonstrated superior efficacy, achieving a median progression-free survival of 6.9 months compared to 3.1 months with investigator’s choice therapy (HR, 0.42; 95% CI, 0.30–0.59; p<0.0001), reducing the risk of progression or death by 58%. It also delivered a significantly higher objective response rate of 37.1% (including five complete responses) versus 5.8% and an improved disease control rate of 73.3% versus 31.1%.
• The combination therapy showed a manageable safety profile. While treatment-related adverse events (TRAEs) occurred in 98.3% of patients receiving darovasertib plus Xalkori versus 89.0% with investigator’s choice therapy, serious TRAEs were lower with the combination (9.2% vs 25.0%). Discontinuations due to TRAEs were also lower for darovasertib and Xalkori (2.5% vs 19.0%), supporting its potential as a new standard of care.
• Darovasertib plus Xalkori holds a differentiated competitive position as there are currently no other approved or late-stage competitors specifically targeting first-line HLA A*02:01-negative metastatic uveal melanoma, addressing an underserved patient population. GlobalData forecasts global sales of darovasertib to reach $709 million by 2032, with a planned NDA submission in the second half of 2026, positioning Ideaya to capture a US market opportunity.

OptimUM-02: Darovasertib + Xalkori's Efficacy and Safety in mUM

The CHOPIN trial represents a significant advancement in metastatic uveal melanoma treatment, demonstrating the potential of combining locoregional and systemic approaches. This single-center, randomized phase 2 study enrolled 76 patients with unresectable liver-only or liver-dominant disease, comparing percutaneous hepatic perfusion with melphalan alone versus combination therapy with ipilimumab and nivolumab. The combination approach achieved a remarkable 1-year progression-free survival of 54.7% compared to 15.8% with perfusion alone, representing an adjusted hazard ratio of 0.34 (p=0.0002). However, this enhanced efficacy came at the cost of increased toxicity, with grade 3-4 treatment-related adverse events occurring in 82% of combination patients versus 41% with perfusion alone, including one treatment-related death due to triple M syndrome.

Tebentafusp continues to demonstrate consistent activity across multiple studies, as evidenced by a comprehensive 2025 meta-analysis encompassing 18 studies and approximately 1,150 HLA-A*02:01-positive patients. The pooled analysis confirmed modest response rates with objective response rates of 7% and disease control rates of 46%, yet meaningful survival benefits with median overall survival of 19.78 months and 1-year overall survival of 69%. The safety profile remained manageable with cytokine release syndrome occurring in 86% of patients but mostly low-grade, and grade ≥3 treatment-related adverse events in 40% with discontinuation rates of approximately 2%. Treatment-naïve patients demonstrated superior outcomes across all metrics compared to previously treated patients, supporting earlier intervention strategies.

Emerging therapeutic approaches show promise for addressing the heterogeneous nature of metastatic uveal melanoma. The transarterial immunoembolization study with GM-CSF achieved a 17% objective response rate exclusively in patients receiving concurrent immune checkpoint inhibitors, with durable responses lasting up to 46 months, though immune-related adverse events occurred in 70% of patients receiving combination anti-CTLA-4/PD-1 therapy. Novel targeted approaches include DYP688, a first-in-class PMEL17-targeting antibody-drug conjugate inhibiting GNAQ/11 signaling, and darovasertib combination studies targeting HLA-A*02:01-negative patients who cannot receive tebentafusp. These developments reflect the field's evolution toward personalized treatment strategies based on molecular and immunologic patient characteristics.

Filling the Gap: Darovasertib + Xalkori in HLA A*02:01-Negative mUM

Recent comparative studies reveal significant variations in efficacy between investigational therapies and standard treatments for metastatic uveal melanoma. The most promising results emerge from combination approaches, particularly stereotactic radiation therapy with immune checkpoint inhibitors, while traditional systemic therapies show limited single-agent activity.

• Combined stereotactic radiation therapy with immune checkpoint inhibitors demonstrated superior outcomes with ORR of 39.1% (CR 8.7%, PR 30.4%), median PFS of 11.6 months (95% CI, 5.4-14.4), and median OS of 27.6 months (95% CI, 16.9-49.1) in 24 patients, representing substantial improvement over historical controls

• Dual-agent immune checkpoint inhibitor therapy significantly outperformed single-agent ICI in pooled analysis: ORR 12.4% vs 3.4% (P<0.001), DCR 44.3% vs 29.3% (P=0.03), and OS 16.3 months vs 9.8 months (P<0.001), though overall ICI monotherapy showed modest pooled ORR of 5.6% and median OS of 11.2 months

• Selumetinib demonstrated statistically significant PFS benefit over chemotherapy in randomized Phase II trial (median PFS 15.9 vs 7 weeks; HR 0.46, P<0.001) with 49% achieving tumor regression compared to no objective responses with chemotherapy, though OS improvement was not statistically significant (11.8 vs 9.1 months; HR 0.66, P=0.09)

• Sorafenib-based regimens showed limited efficacy with sorafenib plus carboplatin/paclitaxel achieving 0% ORR and median OS of 11 months, while sorafenib monotherapy produced no objective responses and 31.2% non-progression rate at 24 weeks with significant toxicity requiring dose modifications in 41.4% of patients

• Liver-directed therapies demonstrated promising local control with percutaneous hepatic perfusion using melphalan achieving 53% partial response rate and no progressive disease, while complete liver resection followed by radiofrequency ablation showed 70% OS at 5 years in highly selected patients with limited hepatic disease

Pivotal Data Unlocks New Path for Metastatic Uveal Melanoma

The recent presentation of primary results from the OptimUM-02 trial marks a pivotal moment for patients battling metastatic uveal melanoma (UM), particularly those who are HLA A02:01-negative. This subgroup has long faced a significant therapeutic void, as the only approved systemic therapy, tebentafusp, is restricted to HLA A02:01-positive individuals. The darovasertib and crizotinib combination has demonstrated a remarkable improvement in progression-free survival, objective response rate, and disease control rate, offering a much-needed and highly effective first-line option.

This success is particularly intriguing given the historical context. Research shows that crizotinib as a monotherapy did not improve recurrence-free survival in the adjuvant setting for high-risk UM. This underscores the critical role of darovasertib, a protein kinase C (PKC) inhibitor, in this combination. The synergy between a PKC inhibitor and crizotinib, a dual ALK/MET inhibitor, suggests a novel and effective approach to targeting the complex biology of UM. This validation of a combination strategy could pave the way for similar multi-pathway targeting in other difficult-to-treat cancers.

For the companies involved, the implications are substantial. Ideaya Biosciences sees its darovasertib validated in a late-stage setting, while Pfizer's crizotinib gains a significant new indication, expanding its utility beyond its established role in ALK/ROS1-positive non-small cell lung cancer. However, careful consideration of the combination's safety profile is paramount, as crizotinib is associated with a range of adverse events, including gastrointestinal issues, visual disturbances, and potential for serious cardiac or liver toxicities. The specific targeting of the HLA A*02:01-negative population also means this solution is not universal for all UM patients, highlighting the continued need for diverse therapeutic strategies across the disease spectrum. This development represents a tangible step forward in refining treatment strategies and improving outcomes for UM patients.