Testing Whether Cancers With Specific Mutations Respond Better to Glutaminase Inhibitor, Telaglenastat Hydrochloride, Anti-Cancer Treatment, BeGIN Study

PRIMARY OBJECTIVE: I. To assess the best overall response rate (BORR) achieved by 6 months of telaglenastat (CB-839) hydrochloride (HCl) treatment in specific pathway aberrant tumors (MPNST, NF1, KEAP1/NRF2 \& STK11/ LKB1). SECONDARY OBJECTIVES: I. To determine the safety, progression-free survival (PFS), time to progression (TTP) and overall survival (OS). II. To determine the overall response rate (ORR) (highest objective response achieved between start of therapy and progression), time to response (TTR) and clinical benefit rate (CBR) of telaglenastat (CB-839)HCl. III. To assess pharmacodynamic changes and adaptive responses and correlate with response to treatment as well as disease progression (correlative objective). EXPLORATORY OBJECTIVES: I. Correlate fludeoxyglucose F-18 (18-F FDG) positron emission tomography (PET)/computed tomography (CT) pre-therapy and 8-weeks post-therapy response to telaglenastat (CB-839) HCl therapy. II. Evaluate changes in level of circulating tumor deoxyribonucleic acid (DNA) at baseline, one month on-treatment and time of progression (Molecular Characterization Laboratory \[MoCHA Labs\]) to treatment response. III. Quantify the peripheral blood concentrations of the metabolites: aspartate, glutamate, glutamine and arginine (@Mayo clinic Oncometabolomics core) and correlate with response. IV. Evaluate the pharmacodynamic (PD) effect of telaglenastat (CB-839) HCl on systemic levels of the tricarboxylic acid (TCA) cycle metabolites in peripheral blood (baseline and one month) as part of the protocol. V. Evaluate tumor by reverse phase protein array (@core facility at MD Anderson) and ribonucleic acid (RNA) sequencing (seq) to evaluate changes from pre-treatment, during treatment and post treatment specimens. VI. Perform patient-derived tumor xenograft (PDX) modelling-co-clinical trials (@Dr. Funda Meric-Bernstam's lab MD Anderson) to understand response/resistance mechanisms and also evaluate combination therapies for future development. OUTLINE: Patients receive telaglenastat hydrochloride orally (PO) twice daily (BID) on days 1-28. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients also undergo CT, magnetic resonance imaging (MRI), or PET/CT during screening and on study, and collection of blood samples during screening and on study. After completion of study treatment, patients are followed up every 3 months thereafter.