Palvella Therapeutics Inc. (NASDAQ: PVLA) announced the publication of a review article in the Journal of Vascular Anomalies examining differences between microcystic and macrocystic lymphatic malformations.

The publication, titled "Microcystic and Macrocystic Lymphatic Malformations: Distinct Genetics and Clinical Strategies," outlines clinical differences between the two subtypes of lymphatic malformations. The review emphasizes that microcystic lymphatic malformations represent a distinct medical challenge compared to macrocystic forms.

According to the research, microcystic lymphatic malformations are characterized by small, diffuse cysts less than 2 centimeters in diameter that form dense networks infiltrating surrounding tissues. These malformations typically occur on cutaneous tissue or in the oral cavity and present with persistent lymphorrhea, bleeding, and increased infection risk. The condition shows no spontaneous regression and generally worsens over time.

In contrast, macrocystic lymphatic malformations feature larger fluid-filled cysts greater than 2 centimeters in diameter, commonly located in deeper internal areas such as the neck, axilla, or mediastinum. These may show spontaneous regression and typically respond better to interventional treatments like sclerotherapy.

The publication notes that no FDA-approved therapies currently exist for microcystic lymphatic malformations, which affects an estimated 30,000 diagnosed patients in the United States.

The research supports the scientific rationale for Palvella's QTORIN rapamycin gel, which recently met its primary endpoint in a Phase 3 clinical trial for treating microcystic lymphatic malformations. The company stated that systemic rapamycin levels remained below 2 nanograms per milliliter across all measured timepoints during the trial.

The review was authored by Maria Buethe, Chief of Pediatric Dermatology Division at Rady Children's Hospital of Orange County and University of California, Irvine, among other researchers.