Population Pharmacokinetic Modeling and Exposure‐Response Analyses of Nemtabrutinib in Patients With Hematologic Malignancies

Nemtabrutinib is a Bruton's tyrosine kinase (BTK) inhibitor under clinical investigation in patients with hematologic malignancies, including chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL/SLL). Nemtabrutinib plasma concentration data from 578 patients enrolled in phase 1 and 2 clinical studies, treated with doses from 5 to 80 mg daily were used to develop a preliminary population pharmacokinetic (PK) model. A two-compartment model with first-order absorption with time delay, and first-order elimination described the data accurately. A full covariate modeling approach was adopted to evaluate prespecified clinically meaningful covariates. The final model included the impact of body weight, sex, race, and disease indication on clearance (CL) and central volume of distribution; age, albumin, moderate CYP3A4 inducers, strong CYP3A4 inhibitors, mild hepatic and moderate renal impairment on CL; and acid reducing agents (ARAs) (i.e., proton pump inhibitors, H2 antagonists, and antacids) on bioavailability. The effect of CYP3A4 modulators and ARAs was estimated to be very low (< 4%) and none of the intrinsic factors were found to have a clinically significant impact on nemtabrutinib PK. Preliminary exposure-efficacy analysis in patients with CLL/SLL showed a significant trend of increased probability of best overall response with increased exposure to nemtabrutinib, while preliminary exposure-safety in patients with hematologic malignancies showed a significant trend between increased exposure and increased probability of any-grade drug-related adverse events (as assessed by investigator) and any-grade hypertension events. Taken together, these exposure-response analyses suggest that 65 mg daily is an appropriate dose for nemtabrutinib monotherapy treatment of patients with CLL/SLL.