Study of Oral MRT-2359 in Selected Cancer Patients

Phase 1 enrollment population: * NSCLC * SCLC * High-grade neuroendocrine cancer of any primary site * Any solid tumors with L-MYC or N-MYC amplification * DLBCL Phase 2 enrollment population: * Any solid tumors with L-MYC or N-MYC amplification * NSCLC with high or low L-MYC or N-MYC expression status (testing will be provided) or SCLC * HR-positive, HER2-negative breast cancer - MRT-2359 in combination with fulvestrant * Non-neuroendocrine prostate cancer - MRT-2359 in combination with enzalutamide Phase 1 and Phase 2 Inclusion Criteria: * Have a selected advanced solid tumor or DLBCL (listed above) for which there are no further standard therapeutic options available * Be age ≥ 18 years and willing to voluntarily complete the informed consent process * A predicted life expectancy of ≥ 3 months and an ECOG performance status ≤ 2 * Have measurable disease by RECIST 1.1 (Eisenhauer et al., 2009) in case of solid tumors or Revised Response Criteria for Malignant Lymphoma (Phase 1 only) (Cheson et al., 2014) in case of DLBCL * Have adequate organ function defined by the selected laboratory parameters * If female of childbearing potential, avoid becoming pregnant and agree to use acceptable methods of contraception after informed consent, throughout the study, and for 90 days after the last dose of MRT-2359 * Male of reproductive potential must use an approved methods of contraception from informed consent until 90 days after study discharge Exclusion Criteria: * Have rec…