A Study of Alectinib and Duvelisib in People With Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma (ALK+ALCL)

Inclusion Criteria: * Pathologically-confirmed diagnosis of ALK+ ALCL by WHO/ICC, classification procedures in use at the time of diagnosis. Note that ALK+ ALCL by definition expresses ALK, which is readily detectable on standard IHC. Confirmation through molecular sequencing of the specific ALK translocation and fusion partner is not necessary for enrollment. * Relapsed or refractory disease after at least one line of prior systemic therapy. * NOTE: Prior systemic therapy must have included at least one cytotoxic chemotherapy agent. * NOTE: Prior treatment with an ALK inhibitor is allowed. * NOTE: Patients being treated with an ALK inhibitor immediately prior to enrollment are eligible. This includes patients on an ALK inhibitor who are in clinical remission at the time of enrollment, as long as the patient is not immediately planned for allogeneic transplant. * NOTE: If the last therapy was an ALK inhibitor, the patient must not have stopped the ALK inhibitor and maintained clinical remission (no relapse) with no intervening therapy for ≥ six months. * NOTE: Prior progression on ALK inhibitor is not specifically exclusionary though should be reviewed with the MSK Principal Investigator. * Age ≥ 18 years at the time of enrollment * ECOG performance status ≤ 2 at the time of enrollment. * Laboratory criteria: * Absolute neutrophil count ≥ 1.0 K/mcL or ≥ 0.5 K/mcL if due to lymphoma (NOTE: growth factor is allowed). * Platelet count ≥ 75 K/uL. * Calculated c…