Novel PI3Kδ Inhibitor Roginolisib Shows Promise in Phase 2 Trial for Metastatic Uveal Melanoma
Key Insights
The randomized phase 2 OCULE-01 trial is evaluating roginolisib, a novel PI3Kδ (search) inhibitor, in approximately 85 patients with metastatic uveal melanoma (search) who progressed after prior therapy.
Phase 1 data from 29 uveal melanoma (search) patients showed median overall survival of 16 months compared to 7 months with historical second-line immunotherapy (search) controls.
Roginolisib demonstrated excellent tolerability at 80 mg daily with less than 7% grade 3/4 treatment-related adverse events and no dose modifications required.
The randomized phase 2 OCULE-01 trial is advancing evaluation of roginolisib, a novel non-ATP competitive allosteric modulator of PI3Kδ (search), in patients with metastatic uveal melanoma (search) following encouraging early-phase results that exceeded historical survival benchmarks.
Phase 1 Results Drive Phase 2 Development
The OCULE-01 trial builds on promising data from the two-part phase 1 DIONE-01 study, which evaluated roginolisib in 24 patients with pretreated solid tumors (search) and follicular lymphoma (search), followed by a dose-confirmation cohort in 20 patients with uveal melanoma (search).
Among 29 patients with uveal melanoma (search) enrolled across both DIONE-01 cohorts, the median overall survival reached 16 months, substantially exceeding the 7-month median OS historically observed with second-line immunotherapy (search). The median progression-free survival was 5 months compared with less than 3 months in historical controls, according to developer iOnctura (search).
"Early data with roginolisib in uveal melanoma (search) suggest an association with reversal of Treg-to-CD8 ratios but also show early signs of clinical benefit in early-phase clinical studies, with some patients doing better than expected," said Paul Nathan, MBBS, PhD, MRCP, consultant medical oncologist at Mount Vernon Cancer Centre (search) in England.
Favorable Safety Profile Supports Continued Development
Roginolisib demonstrated excellent tolerability at the recommended phase 2 dose of 80 mg daily, with less than 7% of grade 3/4 treatment-emergent adverse effects deemed related to the agent. No immune-mediated or dose-limiting toxicities were reported, and unlike prior PI3Kδ (search) inhibitors, no dose modifications were required.
The agent showed long-term tolerability, with treatment durations extending up to 4.5 years in some patients. Translational analyses revealed reductions in immune-suppressive cell populations and chemokines, decreases in circulating tumor DNA from uveal melanoma (search)-associated clones, and suppression of PI3K-related signaling.
Targeting Immune Suppression in Uveal Melanoma
The therapeutic rationale centers on PI3Kδ (search) pathway activation in tumors with immunosuppressed phenotypes. Nathan explained that overactivation of this pathway, known from rare inherited conditions that cause immunosuppression, appears involved in suppressing immune responses to tumors.
"We see changes in the balance of T regulatory cells compared with cytotoxic T cells, as well as other changes in the immune microenvironment, that lead to suppressed immune responses," Nathan noted.
Roginolisib, a small-molecule inhibitor of the PI3Kδ (search) isoform, appears to shift the immune microenvironment toward a more activated state. Early data show reductions in regulatory T cell infiltrate and changes in myeloid-derived suppressor cells.
Phase 2 Trial Design and Endpoints
The OCULE-01 trial will randomize approximately 85 adults with disease progression following at least one prior therapy to receive either roginolisib at 80 mg or 40 mg daily, or investigator's choice of standard therapy. The primary endpoint is overall survival, with secondary endpoints including progression-free survival, objective response, duration of response, disease control, safety, pharmacokinetics, healthcare utilization, and quality-of-life measures.
"This ongoing randomized phase 2 trial is comparing roginolisib with the standard of care in patients who have progressed after prior immunotherapy (search). The primary end point is overall survival, which is a robust end point," Nathan said.
The trial includes mandated tumor biopsies at baseline and after defined drug exposure periods to evaluate effects on the tumor microenvironment, providing crucial mechanistic insights into the drug's activity.
Addressing Critical Unmet Need
Uveal melanoma (search) represents a significant area of unmet medical need despite its rarity. "Uveal melanoma is an area of huge unmet need. Huge in terms of the amount of need, rather than the number of patients, because it's a relatively rare disease. For these patients, we struggle to keep them well for a long time," Nathan emphasized.
The disease is characterized by an immunosuppressed tumor microenvironment, making it particularly suitable for PI3Kδ (search) pathway targeting. The OCULE-01 trial aims to provide definitive randomized data on whether roginolisib can deliver clinically meaningful survival gains in this challenging malignancy.