Analysis of US Food and Drug Administration Oncology Approvals on the Characterization of Hepatic Impairment Effect and Dosing Recommendations

Effect of Hepatic Impairment on Trilaciclib Pharmacokinetics

Trilaciclib is a first-in-class, intravenous cyclin-dependent kinase 4 and 6 inhibitor approved for reducing the incidence of chemotherapy-induced myelosuppression in adult patients with extensive-stage small cell lung cancer receiving a platinum/etoposide-containing or topotecan-containing regimen. No dose adjustment is recommended for participants with mild hepatic impairment (HI) based on previous population pharmacokinetic (PK) analysis. This open-label, parallel-group study examined the impact of moderate and severe HI on the PK of trilaciclib. The study employed a reduced study design. Participants with moderate (Child-Pugh B, n = 8) and severe (Child-Pugh C, n = 5) HI and matched healthy controls (n = 11) received a single intravenous dose of trilaciclib 100 mg/m2. The unbound fraction of trilaciclib was comparable between the HI groups and the matched healthy control group. The unbound trilaciclib extent of exposure (i.e., area under the concentration-time curve) in participants with moderate and severe HI was ∼40% and ∼60% higher, respectively, compared with healthy matched controls based on Child-Pugh classification. Ad hoc analysis using National Cancer Institute classification showed similar results. The US Food and Drug Administration-approved trilaciclib dose of 240 mg/m2 should be reduced by ∼30%, to 170 mg/m2, for patients with moderate or severe HI.

Rare oncology therapeutics: review of clinical pharmacology package of drug approvals (2019-2023) by US FDA, best practices and recommendations

There are many challenges with rare diseases drug development and rare oncology indications are not different. To understand the regulatory landscape as it relates to application of clinical pharmacology principles in rare oncology product development, we reviewed publicly available information of 39 approvals by US FDA between January 2019 and March 2023. The objective was to understand the expected clinical pharmacology studies and knowledge base in such approvals. Model informed drug development (MIDD) applications were also reviewed, as such approaches are expected to play a critical role in filling clinical pharmacology gaps in rare oncology, where number of clinical trials and size of these trials will perhaps continue to be small. The findings highlighted how clinical pharmacology contributed to the evidence of effectiveness, dose optimization and elucidation of intrinsic and extrinsic factors affecting drug's behavior. Clinical pharmacology studies were often integrated with modeling in many of the NDAs/BLAs. Of the post marketing requirements (PMR) received, 18% were for dose optimization, 49% for DDI, 8% for QTc, 49% for specific population, and 5% for food effect. Two post marketing commitments (PMC) were issued for immunogenicity of the 11 biologics submissions. 15% (6 of 39) of the submissions used maximum tolerated dose (MTD) to advance their molecule into Phase 2 studies. Of them 3 approvals received PMR for dose optimization. 3 + 3 was the most prevalent Phase 1 design with use in 74% of the New Drug Applications (NDA)/Biologic License Applications (BLA) reviewed. Rest used innovative approaches such as BLRM, BOIN or mTPi, with BLRM being the most common. Seamless clinical pharmacology and MIDD approaches are paramount for rare oncology drug development.

A phase I, open-label, single-dose study to evaluate the effect of hepatic impairment on the pharmacokinetics and safety of futibatinib

Futibatinib is a covalently binding FGFR1-4 inhibitor that received US Food and Drug Administration approval for the treatment of patients with previously treated, advanced intrahepatic cholangiocarcinoma harboring FGFR2 gene fusions/rearrangements. This phase I trial evaluated the pharmacokinetics (PKs), safety, and tolerability of futibatinib in subjects with impaired hepatic function and matched healthy volunteers. Twenty-two subjects with hepatic impairment (8 mild [Child-Pugh 5-6], 8 moderate [7-9], and 6 severe [10-15]) and 16 matched healthy control subjects received a single oral dose of futibatinib 20 mg. Futibatinib PKs were compared between subjects with mild/moderate/severe hepatic impairment and each corresponding control cohort and the overall control cohort. Relationships between futibatinib PKs and Child-Pugh scores and liver function tests were examined via scatter/regression plots. Compared with matched controls, the area under the plasma concentration-time curve from time zero to infinity increased by 21%/20%/18% and the maximum plasma concentration (Cmax ) increased by 43%/15%/10% in subjects with mild/moderate/severe hepatic impairment, respectively. Changes were not considered clinically relevant: geometric mean ratios were within 80%-125%, except for Cmax in subjects with mild hepatic impairment (143%). No obvious trends were observed among futibatinib PK parameters versus Child-Pugh scores, bilirubin, albumin, international normalized ratio, and aspartate aminotransferase (all p > 0.05). Futibatinib was well-tolerated, with only four grade 1 treatment-emergent adverse events (mild hepatic impairment = 2 and control = 2). The results demonstrate that futibatinib dose adjustments due to mild/moderate/severe hepatic impairment are not necessary in patients receiving futibatinib 20 mg daily.

Design and conduct considerations for studies in patients with hepatic impairment

Despite the liver being the primary site for clearance of xenobiotics utilizing a myriad of mechanisms ranging from cytochrome P450 enzyme pathways, glucuronidation, and biliary excretion, there is a dearth of information available as to how the severity of hepatic impairment (HI) can alter drug absorption and disposition (i.e., pharmacokinetics [PK]) as well as their efficacy and safety or pharmacodynamics (PD). In general, regulatory agencies recommend conducting PK studies in subjects with HI when hepatic metabolism/excretion accounts for more than 20% of drug elimination or if the drug has a narrow therapeutic range. In this tutorial, we provide an overview of the global regulatory landscape, clinical measures for hepatic function assessment, methods to stage HI severity, and consequently the impact on labeling. In addition, we provide an in-depth practical guidance for designing and conducting clinical trials for patients with HI and on the application of modeling and simulation strategies in lieu of dedicated trials for dosing recommendations in patients with HI.