FDA Has Approved Afinitor for Rare SEGA Brain Tumors
This past Friday, the U.S. Food and Drug Administration approved the cancer drug Afinitor (everolimus) to treat patients with subependymal giant cell astrocytoma (SEGA) who can not be treated with surgery.
SEGA is associated with tuberous sclerosis complex (TSC), a rare genetic disorder. SEGAs are considered a major diagnostic feature of TS. These slow growing tumors are seen in 6% to 9% of TSC patients.
TSC 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. TSC 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.
Current estimates place TSC-affected births at one in 6,000. Nearly 1 million people worldwide are known to have TSC, with approximately 50,000 in the United States.
Three types of brain tumors are associated with TSC: cortical tubers, which generally form on the surface of the brain; subependymal nodules, which form in the walls of the ventricles (the fluid-filled cavities of the brain); and giant-cell astrocytomas, a type of tumor that can block the flow of fluids within the brain.
There is currently no cure for TSC. Antiepileptic drugs may be used to control seizures. Surgery, including dermabrasion and laser treatment, may be useful for treatment of skin lesions. Surgery can be used to remove some of the brain tumors. The FDA approval of Afinitor adds another option for the SEGAs that can not be treated with surgery.
“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 which allows approval of 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.
A single study of 28 patients was used to evaluate the safety and effectiveness of Afinitor 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 percent reduction in space the tumor occupied at time of last follow up.
Patients participating in the study did not develop any new tumors. It is important to note, however, that 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 Afinitor 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, for prophylaxis of organ rejection in adult patients at low-moderate immunologic risk receiving a kidney transplant.
Afinitor is marketed by East Hanover, N.J.-based Novartis.
For more information on tuberous sclerosis complex:
Tuberous Sclerosis Alliance
National Institute of Neurological Disorders and Stroke