Summary

This phase III trial investigates the best dose of vinblastine in combination with selumetinib and the benefit of adding vinblastine to selumetinib compared to selumetinib alone in treating children and young adults with low-grade glioma (a common type of brain cancer) that has come back after prior treatment (recurrent) or does not respond to therapy (progressive). Selumetinib is a drug that works by blocking a protein that lets tumor cells grow without stopping. Vinblastine blocks cell growth by stopping cell division and may kill cancer cells. Giving selumetinib in combination with vinblastine may work better than selumetinib alone in treating recurrent or progressive low-grade glioma.

Objectives

PRIMARY OBJECTIVES:
I. To determine the maximum tolerated dose/recommended phase 2 dose (MTD/RP2D) of selumetinib sulfate (selumetinib) + vinblastine sulfate (vinblastine) for children with progressive or recurrent low-grade gliomas (LGGs).
II. To determine if selumetinib + vinblastine will lead to improved event-free survival (EFS) outcome compared with selumetinib alone for children with progressive or recurrent LGGs.

SECONDARY OBJECTIVES:
I. To estimate the objective response rates and overall survival associated with treatment with selumetinib + vinblastine versus single-agent selumetinib.
II. To estimate the difference in EFS and response rate between patients with BRAF rearranged LGG and patients with non-BRAF rearranged LGG after treatment with selumetinib + vinblastine versus single-agent selumetinib.
III. To evaluate toxicities associated with selumetinib + vinblastine and single-agent selumetinib for children with progressive or recurrent LGGs.
IV. To compare the quality of life among patients treated with selumetinib + vinblastine and single-agent selumetinib.
V. To examine the vision outcomes among patients with optic pathway gliomas (OPGs) treated with selumetinib + vinblastine and single-agent selumetinib.

EXPLORATORY OBJECTIVE:
I. To obtain paired blood and tumor specimens for future biology studies, including studies to correlate genomic drivers to response.

OUTLINE: This is a dose-escalation feasibility study of vinblastine sulfate in combination with selumetinib, followed by a randomized efficacy study. Patients in the feasibility study are assigned to Arm I, while patients in the efficacy study are randomized to Arm I or Arm II.

ARM I: Patients receive vinblastine sulfate intravenously (IV) over 1 minute or IV infusion on days 1, 8, 15, and 22 and selumetinib sulfate orally (PO) twice daily (BID) on days 1-28. Treatment repeats every 28 days. Patients receive selumetinib and vinblastine for a total duration of 17 cycles followed by 10 additional cycles of selumetinib alone in the absence of disease progression or unacceptable toxicity. Patients undergo magnetic resonance imaging (MRI) throughout the trial. Patients also undergo blood sample collection during screening and on study.

ARM II: Patients receive selumetinib sulfate PO BID on days 1-28. Treatment repeats every 28 days for up to 27 cycles in the absence of disease progression or unacceptable toxicity. Patients undergo MRI throughout the trial. Patients also undergo blood sample collection during screening and on study.

After completion of study treatment, patients are followed up every 3 months for year 1, every 6 months for years 2-3, and annually for years 4-5.

Eligibility

1. Feasibility phase: patients must be >= 2 years and =< 21 years of age at the time of enrollment
2. Efficacy phase: patients must be >= 2 years and =< 25 years of age at the time of enrollment * All patients > 21 years of age at the time of enrollment must have had initial diagnosis of low-grade glioma by 21 years of age
3. Patients must have a body surface area (BSA) of >= 0.5 m^2 at enrollment
4. Patients must have eligibility confirmed by rapid central pathology and central molecular screening reviews performed on APEC14B1 * Non-neurofibromatosis type 1 (non-NF1), non-tuberous sclerosis complex (non-TSC) low-grade glioma (LGG) without a BRAFV600E or IDH1 mutation * Patients must have progressive or recurrent LGG. Note: Biopsy may be at either initial diagnosis or recurrence * Patients must have measurable disease, defined as having a two-dimensional measurable tumor volume of >= 1 cm^2 ** Tumor size will be measured to include both solid and cystic components of the tumor (whether or not tumor is enhancing) + fluid attenuated inversion recovery (FLAIR) signal * Eligible histologies will include all tumors considered low-grade glioma or low-grade astrocytoma (World Health Organization [WHO] grade 1 and II) by the WHO Classification of Tumors of the Central Nervous System – 4th Edition Revised, with the exception of subependymal giant cell astrocytoma * Patients with metastatic disease or multiple independent primary LGGs are eligible
5. Patients must be progressive or recurrent after having been treated with at least one prior tumor-directed therapy before enrollment
6. Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study * Myelosuppressive chemotherapy: Must not have received within 2 weeks of entry onto this study (4 weeks if prior nitrosourea); * Biologic (anti-neoplastic agent): At least 7 days since the completion of therapy with a biologic agent; * Radiation therapy (RT): >= 2 weeks (wks) for local palliative RT (small port); >= 6 months must have elapsed if prior craniospinal RT or if >= 50% radiation of pelvis; >= 6 wks must have elapsed if other substantial bone marrow (BM) radiation; * Antibodies: >= 21 days must have elapsed from infusion of last dose of antibody, and toxicity related to prior antibody therapy must be recovered to =< grade 1; * MEK inhibitor or vinblastine: Must not have received treatment with a MEK inhibitor or vinblastine within 6 months of study enrollment
7. Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^ 2 or a serum creatinine based on age/gender as follows (within 7 days prior to enrollment): * 2 to < 6 years: 0.8 mg/dL (male) 0.8 mg/dL (female) * 6 to < 10 years: 1 mg/dL (male) 1 mg/dL (female) * 10 to < 13 years: 1.2 mg/dL (male) 1.2 mg/dL (female) * 13 to < 16 years: 1.5 mg/dL (male) 1.4 mg/dL (female) * >= 16 years: 1.7 mg/dL (male) 1.4 mg/dL (female)
8. Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment) (children with a diagnosis of Gilbert’s syndrome will be allowed on study regardless of their total and indirect [unconjugated] bilirubin levels as long as their direct [conjugated] bilirubin is < 3.1 mg/dL)
9. Serum glutamic pyruvic transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L (within 7 days prior to enrollment) * Note: For the purpose of this study, the ULN for SGPT (ALT) has been set to the value of 45 U/L
10. Albumin >= 2 g/L (within 7 days prior to enrollment)
11. Left ventricular ejection fraction (LVEF) >= 53% (or institutional normal; if the LVEF result is given as a range of values, then the upper value of the range will be used) by echocardiogram (within 4 weeks prior to enrollment)
12. Corrected QT interval (QTc interval) =< 450 msec by electrocardiogram (EKG) (within 4 weeks prior to enrollment)
13. Absolute neutrophil count >= 1,000/uL (unsupported) (within 7 days prior to enrollment)
14. Platelets >= 100,000/uL (unsupported) (within 7 days prior to enrollment)
15. Hemoglobin >= 8 g/dL (may be supported) (within 7 days prior to enrollment)
16. Patients with a known seizure disorder should be stable and should not have experienced a significant increase in seizure frequency within 2 weeks prior to enrollment
17. Stable neurological examination for >= 1 week
18. HYPERTENSION: * Patients 2-17 years of age must have a blood pressure that is =< 95th percentile for age, height, and gender at the time of enrollment (with or without the use of anti-hypertensive medications); * Patients >= 18 years of age must have a blood pressure =< 130/80 mmHg at the time of enrollment (with or without the use of anti-hypertensive medications) * Note for patients of all ages: Adequate blood pressure can be achieved using medication for the treatment of hypertension
19. All patients must have ophthalmology toxicity assessments performed within 4 weeks prior to enrollment
20. For all patients, an MRI of the brain (with orbital cuts for optic pathway tumors) and/or spine (depending on the site[s] of primary disease) with and without contrast must be performed within 4 weeks prior to enrollment * Note: If surgical resection or biopsy is performed at the time of progression or recurrence, a post-operative MRI is required
21. Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, or 2. Use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
22. Patients must have the ability to swallow whole capsules