Phase 3: QTORIN™ Rapamycin Meets All Primary, Secondary Endpoints in Microcystic Lymphatic Malformations

Key Takeaways

• QTORIN™ rapamycin met its primary endpoint and all secondary endpoints in the Phase 3 SELVA study (all P < .001).

• At Week 24, 86% of evaluable patients were rated “Much Improved” or “Very Much Improved.”

• If approved, QTORIN™ would be the first FDA-approved therapy for microcystic lymphatic malformations.

Palvella Therapeutics, Inc. announced positive topline results from the Phase 3 SELVA trial evaluating QTORIN™ 3.9% rapamycin anhydrous gel for microcystic lymphatic malformations (microcystic LMs), a rare, congenital vascular anomaly with no US Food and Drug Administration (FDA)-approved therapies. The single-arm, baseline-controlled study met its primary endpoint and all key secondary endpoints with statistical significance (all P < .001). The company plans to submit a New Drug Application (NDA) in the second half of 2026, with potential FDA approval in the first half of 2027.

SELVA enrolled 51 participants aged ≥3 years across leading US vascular anomaly centers; 50 initiated treatment. Efficacy analyses were conducted in the intent-to-treat (ITT) population of participants aged ≥6 years (n = 49). At Week 24, once-daily QTORIN™ rapamycin achieved a mean +2.13-point improvement on the 7-point Microcystic Lymphatic Malformation Investigator Global Assessment (mLM-IGA), meeting the primary endpoint (P < .001). Among those who completed the efficacy period (n = 43), 95% demonstrated ≥1-point improvement and 86% were rated “Much Improved” or “Very Much Improved.”

The blinded key secondary endpoint, the mLM Multi-Component Static Scale (mLM-MCSS), improved by a mean of −3.36 points (P < .001). Additional secondary endpoints—including Patient Global Impression of Change, live mLM-MCSS, Clinician Global Impression of Severity, and Patient Global Impression of Severity—also demonstrated statistically significant improvement (all P < .001).

“For the first time, we have robust, statistically significant Phase 3 data showing that a pharmacologic targeted therapy can meaningfully improve disease severity in this chronically debilitating condition,” said Joyce M. Teng, MD, PhD, Professor of Dermatology and Pediatrics at Stanford University School of Medicine and SELVA principal investigator.

QTORIN™ rapamycin was generally well tolerated. Among treated participants (n = 50), 70% experienced treatment-emergent adverse events; most were mild or moderate. Seventeen participants experienced treatment-related adverse events, most commonly application-site acne, discoloration, or pruritus (each 6%). Systemic rapamycin levels remained below 2 ng/mL at all timepoints.

QTORIN™ rapamycin has received Breakthrough Therapy, Orphan Drug, and Fast Track designations from the FDA for microcystic LMs.