Pediatric Otolaryngology - Head and Neck Surgery Fellow Seattle Children's Hospital/University of Washington Seattle Children's Hospital/University of Washington
Introduction: Management of head and neck PIK3CA-related overgrowth spectrum (PROS) conditions is challenging as multiple invasive procedures often leave persistent malformation and impaired function. Targeted medical therapy using the PI3K inhibitor, apelisib, has not been previously reported for treatment of head and neck PROS conditions, including PIK3CA-induced head and neck lymphatic malformations. This study reports the effects of apelisib on function in pediatric patients with head and neck PROS conditions.
Methods: Prospective IRB-approved cohort study of five patients with PROS conditions, placed on alpelisib (50mg/day per Novartis extended use protocol). Demographics, adverse events, serial photos, functional outcomes, and endoscopic data were collected throughout.
Results: Median participant age at treatment initiation was 4 years (Range 2-13) and average drug therapy duration was 10 months (range 4-22 months). Participant lymphatic malformation stages 2-5 (n=4) were represented, and one had facial infiltrating lipomatosis. All participants were compliant with therapy and monthly laboratory assessments. No adverse events occurred and participants had normal growth. Serial photos demonstrated changes in facial morphology. Via monthly standardized functional outcomes questionnaire administration, all participants reported: decreased oral bleeding, tongue swelling, drooling, improved chewing, swallowing, vocalization, breathing, better sleep quality, less sadness or anger, and less avoidance of public activities. Common invasive therapy was avoided (i.e., tracheotomy) in all participants. Serial nasopharyngoscopy performed in participants with oral/pharyngeal bleeding, dysphagia and/or snoring demonstrated reduction of pharyngeal inflammation and supraglottic laryngeal edema.
Conclusion: Apelisib was well tolerated in patients with head and neck PROS conditions. Improved function, quality of life, increased upper airway size and invasive procedure reduction was observed in all participants.