Population modeling analyses of crizotinib in pediatric patients with ALK-positive advanced cancers.

BACKGROUND: Alterations in the ALK (anaplastic lymphoma kinase) gene play a critical role in pathogenesis of anaplastic large cell lymphoma (ALCL). Crizotinib is a small molecule competitive inhibitor of ALK, ROS1, and MET kinases and was approved for pediatric patients with ALK-positive relapsed or refractory, systemic ALCL, and ALK-positive unresectable, recurrent, or refractory inflammatory myofibroblastic tumors (IMT). PROCEDURE: Crizotinib data from pediatric patients with relapsed or refractory solid tumors, IMT, or ALCL were included in the analyses. All patients received crizotinib orally at doses ranging from 100 to 365 mg/m2 twice daily (BID). PopPK analyses were conducted to characterize crizotinib disposition in pediatric patients. Exposure-response (ER) safety and antitumor analyses were conducted to characterize relationships between crizotinib dose or exposure with safety and antitumor activity endpoints of interest. RESULTS: The population pharmacokinetic (popPK), ER safety, and ER antitumor analysis included 98, 110, and 36 pediatric patients, respectively. A one-compartment pharmacokinetic model with allometric scaling, first-order elimination, and first-order absorption with lag time adequately described the data. Natural log-transformed model-predicted crizotinib AUCss (steady-state area under the concentration-time curve) demonstrated a significant, positive relationship with Grade ≥3 NEUTROPENIA and Any Grade VISION DISORDER. Crizotinib dose demonstrated a positive relationship with objective response rate. CONCLUSIONS: No significant differences in PK were identified across a wide range of ages or across tumor types, suggesting body surface area (BSA)-based dosing adequately adjusted for differences in patient size to achieve similar systemic crizotinib exposures across young children and adolescent pediatric patients. None of the myelosuppressive events except Grade ≥3 NEUTROPENIA had significant relationships identified with crizotinib dose or exposure, suggesting crizotinib is a tolerable treatment with less hematological toxicity than traditional chemotherapy regimens for pediatric patients with ALK-mutated cancers. Results from the presented analyses support the pediatric dosing recommendations in the product label.

A phase 1/2 study of pepinemab in children, adolescents, or young adults with recurrent or refractory solid tumors: A children's oncology group consortium report (ADVL1614).

PURPOSE: Pepinemab, a humanized IgG4 monoclonal antibody, targets the SEMA4D (CD100) antigen to inhibit binding to its high-affinity receptors (plexin B1/PLXNB1, plexin B2/PLXNB2) and low-affinity receptor (CD72). SEMA4D blockade leads to increased cytotoxic T-cell infiltration, delayed tumor growth, and durable tumor rejection in murine tumor models. Pepinemab was well tolerated and improved T cell infiltration in clinical studies in adults with refractory tumors. SEMA4D was identified as a strong candidate proto-oncogene in a model of osteosarcoma. Based on these preclinical and clinical data, we conducted a phase 1/2 study to determine the recommended phase 2 dose (RP2D), pharmacokinetics, pharmacodynamics, and immunogenicity, of pepinemab in pediatric patients with recurrent/refractory solid tumors, and activity in osteosarcoma. EXPERIMENTAL DESIGN: Pepinemab was administered intravenously on Days 1 and 15 of a 28-day cycle at 20 mg/kg, the adult RP2D. Part A (phase 1) used a Rolling 6 design; Part B (phase 2) used a Simon 2-stage design in patients with osteosarcoma. Pharmacokinetics and target saturation were evaluated in peripheral blood. RESULTS: Pepinemab (20 mg/kg) was well tolerated and no dose-limiting toxicities were observed during Part A. There were no objective responses. Two patients with osteosarcoma achieved disease control and prolonged stable disease. Pepinemab pharmacokinetics were similar to adults. CONCLUSIONS: Pepinemab (20 mg/kg) is safe, well tolerated and resulted in adequate and sustained target saturation in pediatric patients. Encouraging disease control in two patients with osteosarcoma warrants further investigation with novel combination strategies to modulate the tumor microenvironment and antitumor immune response. CLINICAL TRIAL REGISTRY: This trial is registered as NCT03320330 at Clinicaltrials.gov. DISCLAIMER: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.