Testing LOXO-101 as Potentially Targeted Treatment in Cancers With NTRK Genetic Changes (MATCH - Subprotocol Z1E)

PRIMARY OBJECTIVE: I. To evaluate the proportion of patients with objective response (OR) to targeted study agent(s) in patients with advanced refractory cancers/lymphomas/multiple myeloma. SECONDARY OBJECTIVES: I. To evaluate the proportion of patients alive and progression free at 6 months of treatment with targeted study agent in patients with advanced refractory cancers/lymphomas/multiple myeloma. II. To evaluate time until death or disease progression. III. To identify potential predictive biomarkers beyond the genomic alteration by which treatment is assigned or resistance mechanisms using additional genomic, ribonucleic acid (RNA), protein and imaging-based assessment platforms. IV. To assess whether radiomic phenotypes obtained from pre-treatment imaging and changes from pre- through post-therapy imaging can predict objective response and progression free survival and to evaluate the association between pre-treatment radiomic phenotypes and targeted gene mutation patterns of tumor biopsy specimens. OUTLINE: Patients receive larotrectinib (LOXO-101) orally (PO) twice daily (BID) on days 1-28 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Additionally, patients undergo computed tomography (CT) or magnetic resonance imaging (MRI) during screening and on study, as well as during follow-up as clinically necessary. Patients also undergo biopsies and blood sample collection on study. After completion of study treatment, patients are followed every 3 months for 2 years and then every 6 months for 1 year.