Effects of rapamycin on angiomyolipomas in patients with tuberous sclerosis

Tuberous sclerosis (TS) is a systemic disease, with an autosomal dominant pattern of inheritance caused by mutations in two genes (TSC1 and TSC2) that cause tumours (angiomyolipomas [AML], angiofibromas, astrocytomas). Constant and inadequate proliferation occurring in TS may be blocked by mTOR inhibitors (mammalian target of rapamycin), such as rapamycin.

At present, our study includes 17 patients with TS. All had at least one AML greater than 2cm in diameter diagnosed by MRI. They received rapamycin during 12 months. Plasma levels remained stable between 4-8ng/dl. The AML size was monitored every six months by abdominal MRI.

At 12 months of inclusion, MRI indicated a decrease in the size of AML in all patients showing at least a 50% reduction in 82.4% (14/17, 95% CI [56.57%, 96.20%]). The mean percent reduction was 66.3% (95% CI [56.9%, 75.6%], P<.0001). The major side effects observed were: oral aphthous ulcers (5/17); hypertriglyceridemia (3/17); microcytosis and hypochromia (3/17); diarrhea (2/17); acne (1/17); acute pyelonephritis (1/17); and proteinuria (1/17).

These preliminary clinical data suggest that rapamycin can play a beneficial role in the treatment of TS. Our experience in 17 patients treated for 12 months demonstrates safety and efficacy in reducing AML volume.