Physiologically based pharmacokinetic (PBPK) approaches that incorporate the developmental physiology and ontogeny of cytochrome P450 (CYP) enzymes may have value in the design of pediatric trials. Four recent submissions to the US Food and Drug Administration (FDA) incorporated different PBPK applications to pediatric drug development.Further testing of PBPK models for three drugs showed that these models generally under predicted drug clearance. PBPK modeling may have potential for improving pediatric trials through the learn-and-confirm approaches utilized in current regulatory submissions.

On April 29, 2014, the FDA granted accelerated approval to ceritinib (ZYKADIA; Novartis Pharmaceuticals Corporation), a breakthrough therapy-designated drug, for the treatment of patients with anaplastic lymphoma kinase (ALK)-positive, metastatic non-small cell lung cancer (NSCLC) who have progressed on or are intolerant to crizotinib. The approval was based on a single-arm multicenter trial enrolling 163 patients with metastatic ALK-positive NSCLC who had disease progression on (91%) or intolerance to crizotinib. Patients received ceritinib at a starting dose of 750 mg orally once daily. The objective response rate (ORR) by a blinded independent review committee was 44% (95% CI, 36-52), and the median duration of response (DOR) was 7.1 months. The ORR by investigator assessment was similar. Safety was evaluated in 255 patients. The most common adverse reactions and laboratory abnormalities included diarrhea (86%), nausea (80%), increased alanine transaminase (80%), increased aspartate transaminase (75%), vomiting (60%), increased glucose (49%), and increased lipase (28%). Although 74% of patients required at least one dose reduction or interruption due to adverse reactions, the discontinuation rate due to adverse reactions was low (10%). With this safety profile, the benefit-risk analysis was considered favorable because of the clinically meaningful ORR and DOR.

On November 21, 2018, the FDA approved glasdegib (Daurismo; Pfizer), a small-molecule Hedgehog inhibitor, in combination with low-dose cytarabine (LDAC) for treatment of newly diagnosed acute myeloid leukemia (AML) in adults ! 75 years or with comorbidities that preclude use of intensive induction chemotherapy. Evidence of clinical benefit came from Study BRIGHT AML 1003, a randomized trial comparing glasdegibþLDAC with LDAC alone for treatment of newly diagnosed AML in 115 patients either ! 75 years old or ! 55 years old with preexisting comorbidities. Efficacy was established by improved overall survival (OS) with the combination compared with LDAC alone (HR, 0.46; 95% confidence interval, 0.30-0.71; one-sided stratified log-rank P ¼ 0.0002). Median OS was 8.3 months with the combination and 4.3 months with LDAC alone. Common adverse reactions included cytopenias, fatigue, hemorrhage, febrile neutropenia, musculoskeletal pain, nausea, edema, dyspnea, decreased appetite, dysgeusia, mucositis, constipation, and rash. The label includes a boxed warning for embryo-fetal toxicity and a warning for QT interval prolongation. There is a limitation of use for patients with moderate-to-severe hepatic and severe renal impairment; trials studying glasdegib in these patient populations are required as a condition of this approval.See related commentary by Fathi, p. 6015