R115777 to Treat Children With Neurofibromatosis Type 1 and Progressive Plexiform Neurofibromas

Study Summary

This study will examine whether the experimental drug R115777 (Tipifarnib) can shrink or slow the growth of plexiform neurofibromas in children and young adults with neurofibromatosis type 1 (NF1) and determine what side effects are related to treatment. Plexiform tumors arise from nerves; the only effective treatment is surgical removal. Often, however, not all the tumors can be removed, because of their number or location. Patients with NF1 have a reduced amount of the protein neurofibromin. Neurofibromin is thought to help control the activity of another protein, called ras, which regulates cell growth. Too little neurofibromin, therefore, may allow for uncontrolled cell growth and tumor formation. R115777 interferes with the function of the ras and other proteins. In test tube and animal studies, R115777 has blocked the growth of cancer cells. This study will examine whether the drug is effective against plexiform tumors. Patients with NF1 and progressive plexiform neurofibromas between 3 and 25 years of age may be eligible for this study. Patients whose tumors can be successfully removed surgically may not participate in this study. Candidates are screened with a medical history and physical and eye examinations, blood and urine tests, and magnetic resonance imaging (MRI). Photographs are taken of tumors visible on the body surface. Study participants are randomly assigned to receive either R115777 or placebo (an inactive substance). They take R115777 or placebo tablets every 12 hours for 21 days, followed by a 7-day rest period. This constitutes one 28-day treatment cycle. Treatment continues for as long as the tumors remain stable or shrink and side effects are tolerable. The treatment is switched (for example, from placebo to R115777) or stopped if the tumors grow or if side effects become unacceptable. Patients (or their parents) keep a record of side effects. For the first 3 treatment cycles, patients have a physical examination and blood tests every o

Primary Outcome

Median time to progression is defined as a greater than or equal to 20% increase increase in the sum of the volume of all index lesions based on volumetric analysis utilizing magnetic resonance imaging (MRI).Start of phase A or phase B to time of progression.

Interventions

• OTHER placebo
• DRUG tipifarnib