The U.S. Food and Drug Administration approved the cancer drug everolimus (Afinitor? , Novartis) on Friday to treat patients with subependymal giant cell astrocytoma (SEGA) associated with tuberous sclerosis (TS), a rare genetic disorder. This approval was for treatments of SEGA that can not be treated with surgery.
TS causes benign (non-cancerous) tumors to grow in the brain and in other parts of the body including the eyes, lungs, liver, heart, skin and kidneys. TS occurs as a result of genetic mutations that lead to the development of tumors and results in a variety of possible symptoms including learning and developmental disabilities, skin abnormalities, seizures, and lung and kidney disease.
SEGAs are considered a major diagnostic feature of TS and are slow growing tumors, seen in 6% to 9% of patients. The disease can be fatal for patients who develop complications with tumor growth on the brain. Surgery is used to remove the tumor growths in some patients.
“Patients with this disease currently have limited treatment options beyond surgical intervention,” said Richard Pazdur, M.D., director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research. “It is important for research to continue in rare diseases where patients have few or no existing drug treatment options.”
The drug was approved under the FDA’s accelerated approval program. The program allows the FDA to approve a drug to treat serious diseases with an unmet medical need based on an endpoint thought to reasonably predict clinical benefit. The company is required to collect additional long term efficacy and safety data confirming the drug’s benefit. This program provides earlier patient access to promising new or existing drugs while the confirmatory clinical trials are being conducted.
Everolimus was first approved in March 2009 to treat kidney cancer after patients fail treatment with sunitinib (Sutent?, Pfizer) or sorafenib (Nexavar?, Bayer Healthcare/Onyx Pharmaceuticals).
A single study of 28 patients was used to evaluate the safety and effectiveness of everolimus to treat SEGA. At six months into the study, nine patients (32%) had a greater than 50% reduction in space the tumor occupied (tumor volume) of their largest SEGA tumor lesion. The length of time from when a patient’s tumor visibly shrank and then remained stable (duration of response) for these nine patients ranged from about three months to two and one-half years with a median of 266 days. Seven of these patients retained the greater than 50% reduction in space the tumor occupied at time of last follow up.
Patients participating in the study did not develop any new tumors. However, no tumor resolved completely. Four of the patients on this study had previous surgery, but their tumor grew back. After receiving Afinitor, three of these patients experienced greater than 50% reduction in tumor volume.
In patients treated with everolimus for SEGA, the most commonly reported side effects included upper respiratory tract infections, sinus and ear infections, mouth sores, and fever. Common laboratory test abnormalities included liver enzyme elevations, high blood cholesterol and triglycerides (hyperlipidemia), high blood sugar, and decreases in white blood cells, red blood cells (anemia), and platelets. In patients with kidney cancer (renal cell carcinoma), lung inflammation (pneumonitis) and decreases in kidney (renal) function also have been reported.
Everolimus is also approved under an alternative trade name, Zortress? (Novartis), for prophylaxis of organ rejection in adult patients at low-moderate immunologic risk receiving a kidney transplant. Zortress has a different safety profile in these patients.