Study of Oral LOXO-338 in Patients With Advanced Blood Cancers

Inclusion Criteria: * B-cell malignancy. * Patients must have received prior therapy. * Patients must have an objective indication for therapy. * Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-1. * Anticipated life expectancy of greater than or equal to (≥) 12 weeks. * Adequate bone marrow function. * Adequate hepatic function. * Creatinine clearance of ≥ 60 milliliters (mL)/minute. * Ability to swallow tablets. * Ability to comply with outpatient treatment, laboratory monitoring, and required clinic visits for the duration of study participation. * Prior treatment-related adverse events (AEs) must have recovered to grade less than or equal to (≤) 1 or pretreatment baseline, with the exception of alopecia. * Men with partners of childbearing potential or women of childbearing potential (WOCBP) must agree to use highly effective birth control. * WOCBP must not be pregnant. * Additional Inclusion Criteria for Patients with AL Amyloidosis * In Part 1 Dose Expansion, patients with AL amyloidosis are eligible based on prior detection of primary systemic light-chain amyloidosis. * Must have measurable disease of AL amyloidosis. * Prior local fluorescence in-situ hybridization (FISH) testing results for t(11;14) are required to be submitted prior to enrollment. Exclusion Criteria: * Prior to identification of an appropriate RP2D (Dose Expansion) of LOXO-338, a history of known, active or suspected: * Richter's transformation to diffuse large B-cell…