Palvella Therapeutics Inc. (NASDAQ: PVLA) announced that the European Patent Office issued European Patent No. 3565520 covering anhydrous compositions of rapamycin, including the company's QTORIN 3.9% rapamycin anhydrous gel.

The patent provides protection for anhydrous topical compositions and methods of use for QTORIN rapamycin, including treatment of microcystic lymphatic malformations, venous malformations, and other diseases associated with dysregulation of the mammalian target of rapamycin pathway. Patent protection extends until 2038.

"Issuance of this European patent represents an important milestone in expanding our global intellectual property protection for QTORIN rapamycin," said Wes Kaupinen, founder and chief executive officer of Palvella Therapeutics. The patent complements existing issued patents in the United States, Japan, Australia, and other territories covering anhydrous formulations of rapamycin.

QTORIN rapamycin has received European Orphan Drug Designation for treating microcystic lymphatic malformations, which may provide 10 years of market exclusivity in the European Union upon approval. Currently, no approved therapies exist in the European Union for microcystic lymphatic malformations.

The Wayne, Pennsylvania-based clinical-stage biopharmaceutical company is developing QTORIN rapamycin across multiple rare skin diseases and vascular malformations without FDA-approved therapies, including microcystic lymphatic malformations, cutaneous venous malformations, and clinically significant angiokeratomas. The company plans to announce a fourth target clinical indication in the second half of 2026.

The patented compositions relate to Palvella's proprietary QTORIN anhydrous gel formulation designed to locally inhibit the mTOR pathway within affected pathogenic skin tissue while minimizing systemic exposure.