Study of Cabozantinib With Selumetinib for Plexiform Neurofibromas

"Cabozantinib will be taken once a day. It must be swallowed whole and not crushed and taken on an empty stomach. The dose will depend on when a participant enrolls on the study. First group will take 20 mg.~If participants are enrolled early in this study, they may receive doses that are lower than those who are enrolled later. Participants will be told what dose they will take when they start the study. Once a dose is started, the dose will not be increased. However, a dose can be reduced up to 2 times if a participant experience adverse events.~Cabozantinib may be taken simultaneously with selumetinib."

"Selumetinib will be taken twice a day, at least 6 hours apart. It must be swallowed whole and not crushed and taken on an empty stomach. The dose will depend on when a participant enrolls on the study. First group will take 15 mg twice a day.~If participants are enrolled early in this study, they may receive doses that are lower than those who are enrolled later. Participants will be told what dose they will take when they start the study. Once a dose is started, the dose will not be increased. However, a dose can be reduced up to 2 times if a participant experience adverse events."