Palvella Releases Qtorin Clinical Data, Plans FDA New Drug Application

Palvella Therapeutics announced new clinical data from the Phase 3 SELVA and Phase 2 TOIVA studies were reported at the International Society for the Study of Vascular Anomalies World Congress 2026 in Philadelphia. Palvella previously announced positive topline results from the SELVA study in February, including achieving statistical significance on the primary endpoint, key secondary endpoint, and all pre-specified secondary efficacy endpoints. In participants aged 6-11 years, Qtorin rapamycin demonstrated statistically significant improvement on the Microcystic Lymphatic Malformation Investigator Global Assessment of +2.46 at Week 24. In total, 100% of participants in this cohort were rated "Much Improved" or "Very Much Improved" on the mLM-IGA at Week 24. At Week 24, 100% of participants elected to continue Qtorin rapamycin in the Treatment Extension period, reflecting strong interest in ongoing therapy. In microcystic LMs, bleeding and leaking represent some of the most debilitating and hardest-to-control disease manifestations. In participants with moderate or worse leaking/bleeding at baseline, Qtorin rapamycin demonstrated statistically significant improvement on the mLM-IGA Leaking/Bleeding of +2.48 at Week 24. Overall, 87% of participants with moderate or worse leaking/bleeding at baseline were rated as "Much Improved" or "Very Much Improved" on the mLM-IGA Leaking/Bleeding at Week 24. SELVA incorporated multiple structured approaches to capture the patient voice, including both the Treatment Satisfaction Questionnaire for Medication, a patient-reported outcome measure that assesses satisfaction with medication, and patient qualitative interviews. In total, 100% of SELVA participants who completed the efficacy evaluation period were at least somewhat satisfied with Qtorin rapamycin on the TSQM-9 overall satisfaction item at Week 24, with 84% reporting extremely satisfied, very satisfied, or satisfied. A pre-specified patient qualitative interview sub-study was incorporated to capture the patient experience consistent with FDA's Patient-Focused Drug Development framework. Interviews captured patient-reported positive changes in quality-of-life following Qtorin rapamycin treatment. The blinded independent review demonstrated pre-treatment stability during the 8-week run-in period, followed by marked improvement on Qtorin rapamycin, supporting SELVA's single-arm, baseline-controlled design. During the 8-week pre-treatment run-in period, the mean change in the blinded Microcystic Lymphatic Malformation Multi-Component Static Scale score was -0.1. After 24 weeks of treatment, the blinded mean mLM-MCSS score improved by -3.4 points, decreasing from 9.9 at Day 1 to 6.6 at Week 24, representing 48% of the maximum potential improvement from Day 1. Palvella plans to submit a new drug application to the FDA for Qtorin rapamycin for Microcystic LMs in the second half of 2026. Palvella announced TOIVA topline results in December 2025. TOIVA achieved statistical significance on multiple pre-specified clinician-reported and patient-reported efficacy endpoints. TOIVA Phase 2 study demonstrated statistically significant improvements in both cVM-MCSS Height and cVM-MCSS Appearance at all measured time points, with increasing clinical response observed with longer duration of QTORIN(TM) rapamycin therapy. At Week 24, treatment with Qtorin rapamycin demonstrated a mean reduction of 1.50 points in cVM-MCSS Height score. At Week 24, treatment with Qtorin rapamycin demonstrated a mean reduction of 1.43 points in cVM-MCSS Appearance score. Palvella plans to initiate a Phase 3 trial of Qtorin rapamycin for the treatment of cutaneous venous malformations in the second half of 2026. Qtorin rapamycin has received FDA Fast Track Designation for cutaneous venous malformations, and Palvella has submitted an application to FDA for Breakthrough Therapy Designation in this indication.