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A Phase II Study of the mTOR Inhibitor Sirolimus in Neurofibromatosis Type 1 Related Plexiform Neurofibromas


The STOPN trial is designed to determine whether the drug sirolimus slows down disease progression based on volumetric MRI measurements in children and adults with neurofibromatosis type 1 (NF1) and progressive plexiform neurofibromas.


Sirolimus (also called rapamycin) inhibits a protein called “mTOR,” which is hyperactive in neurofibromas.


Children (3 years or older) and adults with NF1 and progressive plexiform neurofibromas that can cause significant morbidity are eligible.


This phase II study will evaluate the activity of sirolimus in children and adults with NF1 and inoperable plexiform neurofibromas that have the potential to cause significant morbidity. The following disease strata will be studied:

  • Stratum 1: Progressive plexiform neurofibroma(s) that have the potential to cause significant morbidity. The endpoint will be time to tumor progression based on volumetric tumor measurements.
  • Stratum 2: Plexiform neurofibromas without documented radiographic progression at trial entry.


  • Brian Weiss, MD, Chair
  • John Perentesis, MD, Co-Chair
  • Brigitte Widemann, MD, Co-Chair
  • Michael Fisher, MD, Co-Chair
  • Bruce Korf, MD, PhD, Co-Chair


The study is complete and closed. Please see trial results via publications or visit clinicaltrials.gov/ct2/show/NCT00634270.