Inclusion Criteria:

          1. Patients aged: > 6 months and < 12 years of age.

          2. Diagnosis of neurofibromatosis type 1 (NF1).

          3. Presence of symptomatic airway plexiform neurofibromas ; defined by abnormal sleep
             study or pulmonary function testing.

          4. Patients must have measurable (> 1.5 cm in two dimensions or able to assess a minimum
             of 3 slices) disease by magnetic resonance imaging (MRI).

          5. Patients must have a Karnofsky of > 70% or Lansky of > 50% and a life expectancy of >
             2 months.

          6. Adequate end organ function, defined as the following:

             total bilirubin < 1.5 x ULN, SGOT and SGPT < 2.5 x UNL, creatinine < 1.5 x ULN, ANC >
             1.5 x 109/L, platelets > 100 x 109/L.

          7. Patients must be able to swallow whole pills or crushed pills in a soft food such as
             pudding or apple sauce; or have other GI access such as a G-tube.

          8. Written, voluntary informed consent/assent.

        Exclusion Criteria:

          1. Patient has received any other investigational agents within 14 days of first day of
             study drug dosing.

          2. Patient is < 5 years free of another primary malignancy except: if the other primary
             malignancy is not currently clinically significant nor requiring active intervention,
             or if other primary malignancy is a basal cell skin cancer or a cervical carcinoma in
             situ. Existence of any other malignant disease is not allowed.

          3. Patient with Grade III/IV cardiac problems as defined by the New York Heart
             Association Criteria. (i.e., congestive heart failure, myocardial infarction within 6
             months of study)

          4. Patient has a severe and/or uncontrolled medical disease (i.e., uncontrolled diabetes,
             chronic renal disease, or active uncontrolled infection).

          5. Patient has a known brain metastasis. Non-specific CNS changes on MRI/CT
             characteristic of NF1 are allowed, but not known CNS malignancies requiring
             therapeutic intervention.

          6. Patient has known chronic liver disease (i.e., chronic active hepatitis, and
             cirrhosis).

          7. Patient has a known diagnosis of human immunodeficiency virus (HIV) infection.

          8. Patient received chemotherapy within 4 weeks (6 weeks for nitrosourea or mitomycin-C)
             prior to study entry.

          9. Patient previously received radiotherapy to > 25 % of the bone marrow

         10. Patient had a major surgery within 2 weeks prior to study entry.

         11. Patient/parent with any significant history of non-compliance to medical regimens or
             with inability to grant reliable informed consent.

         12. Patients who have or anticipate receiving permanent (or semi-permanent) metallic
             structures attached to their body. (e.g., braces on teeth, body piercings), which
             their physicians believe will interfere with the MRI.

         13. Patient has an unstable airway requiring more urgent intervention or deemed unable to
             travel due to unstable airway by referring MD.