Study of Sirolimus Therapy for Segmental Overgrowth Caused by Somatic PI3K Activation

Study Summary

Background: \- PIK3CA-related overgrowth spectrum (PROS) is caused by changes in the PIK3CA gene. This gene makes a protein that communicates with other proteins in the body to cause cells to grow. Alterations in PIK3CA change the chemical signals in the body and cause overgrowth in fatty, vascular and other tissues. Sirolimus is a drug that reduces the signals sent by one of the proteins in this chemical signaling pathway. Researchers want to learn whether the drug sirolimus can reduce or stabilize some of the overgrowth that patients with PROS experience. Objectives: \- To measure how the overgrowth of patients with PROS changes over time and whether taking a drug called sirolimus can reduce or stabilize a person s overgrowth. Eligibility: \- People ages 3 to 65 years old with a confirmed mutation or alteration of the PIK3CA gene in the person s affected tissues (a somatic mutation). Design: * Participants will be screened with medical history and genetic counseling. * First 6 months: Participants will have their overgrowth monitored. * Next 6 months: Participants will take sirolimus once or twice a day. * Participants will have to visit the clinic several times, and stay in the area for 4 to 5 days each time. * Participants will have a one month-long visit to the clinic. * During clinic visits, participants will have: * Blood and urine tests. * Photographs of their physical features. * Scans, including an MRI and DEXA, and possibly x-rays and CT scans. * For the MRI and CT scans, participants will lie in a machine that takes pictures of their body. * The DEXA involves a small amount of radiation. * They may have: * Non-invasive heart function tests. * Lung function tests. * Participants will have several blood and urine tests between visits. * Participants will complete surveys and keep a diary of their treatment and side effects. * Participants may visit other health specialists or undergo other tests based on side effects. * One month after stopping the

Primary Outcome

The primary outcome measures will use quantitative DXA scan of the affected and unaffected body part (s) to demonstrate negative change in fibrofatty, muscular, and/or bony overgrowth. Absolute volumes of affected and unaffected tissue at week 0 (designated X), week 26 (designated Y), and week 52 (designated Z), were compared by taking the difference between the mean value obtained during the run-in period and the mean value obtained during the treatment period. Tissue volume changes (week 0-26

Interventions

• DRUG Sirolimus