STOPN is a Phase II Study of the mTOR Inhibitor Sirolimus in Neurofibromatosis Type-1 Related Plexiform Neurofibromas


The STOPN trial is designed to test the drug Sirolimus for activity in the treatment of plexiform neurofibromas in patients with NF1. Plexiform neurofibromas are tumors that involve a network of nerves and may be present on the surface of the body or deep inside the body. They have a potential to grow and cause disfigurement as well as compression of surrounding structures. Complete surgical removal usually is not possible, although surgery may be done to relieve symptoms or reduce the bulk of the tumor. This trial is targeted at tumors that cannot be treated surgically and have the potential to cause serious medical or cosmetic problems.


Sirolimus (also called rapamycin) inhibits a protein called “mTOR,” which has been found to be hyperactive in neurofibromas. The drug is currently used as a immunosuppressant for transplant patients.


The trial is designed to treat individuals who fulfill diagnostic criteria for NF1 who are at least 3 years of age or older. They must have a plexiform neurofibroma with the potential to cause serious medical problems that can be measured by MRI scanning, they must be able to fully participate in the trial, and they must not have medical problems or be receiving treatments that make them ineligible. A full list of criteria can be obtained by contacting one of the study sites.


The protocol involves regular clinical evaluations, MRI scans, and blood tests to monitor drug levels. Medication is taken orally and is provided at no cost to you. Further details about the protocol can be obtained by contacting one of the study sites.

Current Status

Four STOPN publications are in print with results of this study.