A Phase 1 Study to Evaluate Absolute Bioavailability and Absorption, Distribution, Metabolism, and Excretion of Savolitinib in Healthy Male Volunteers.

Savolitinib is an oral MET (hepatocyte growth factor receptor) tyrosine kinase inhibitor, with demonstrated preliminary efficacy in several cancer types. Previous pharmacokinetics assessments showed that savolitinib is rapidly absorbed but there are limited data on the absolute bioavailability and absorption, distribution, metabolism, and excretion (ADME) of savolitinib. This open-label, two-part, phase 1 clinical study (NCT04675021) used a radiolabeled micro-tracer approach to evaluate absolute bioavailability and a traditional approach to determine the ADME of savolitinib in healthy male adult volunteers (N = 8). Pharmacokinetics, safety, and metabolic profiling and structural identification from plasma, urine, and fecal samples were also assessed. Volunteers received a single oral savolitinib 600 mg dose followed by intravenous 100 µg of [14 C]savolitinib in Part 1 and a single oral 300 mg [14 C]savolitinib dose (≤4.1 MBq [megabecquerel] [14 C]) in Part 2. Following Part 1, absolute oral bioavailability was 69%, the median time of maximum observed concentration was 3.5 hours, and the mean terminal half-life was 6.1 hours. Following Part 2, 94% of the radioactivity administered was recovered, with 56% and 38% in urine and feces, respectively. Exposure to savolitinib and metabolites M8, M44, M2, and M3 accounted for 22%, 36%, 13%, 7%, and 2%, respectively, of plasma total radioactivity. Approximately 3% of the dose was excreted as unchanged savolitinib in urine. Most savolitinib elimination occurred via metabolism by several different pathways. No new safety signals were observed. Our data show that the oral bioavailability of savolitinib is high and the majority of savolitinib elimination occurs via metabolism and is excreted in the urine.

Clinical evaluation of the potential drug-drug interactions of savolitinib: Interaction with rifampicin, itraconazole, famotidine or midazolam.

AIMS: We investigated savolitinib pharmacokinetics (PK) when administered alone or in combination with rifampicin, itraconazole or famotidine, and investigated midazolam PK when administered with or without savolitinib in healthy males. METHODS: Savolitinib PK was evaluated before/after: rifampicin (600 mg once daily [QD] for 5 days); itraconazole (200 mg QD for 5 days); a single dose of famotidine (40 mg QD) 2 hours before savolitinib. Midazolam PK was evaluated before/after midazolam (1 mg QD) with or without savolitinib (600 mg QD). Each study enrolled 20, 16, 16 and 14 volunteers, respectively. Plasma samples were collected to determine the effect on PK. RESULTS: The geometric mean ratios (GMR, %) (90% confidence intervals [CIs]) for savolitinib alone and in combination for Cmax , AUC respectively, were 45.4 (41.4-49.9), 38.5 (34.2-43.3) in the rifampicin study (n = 18); 105.2 (87.7-126.3), 108.4 (96.3-122.1) in the itraconazole study (n = 16); and 78.8 (67.7-91.7), 87.4 (81.2-94.2) in the famotidine study (n = 16). The GMRs (90% CIs) for midazolam alone and in combination with savolitinib for Cmax , AUC respectively, were 84.1 (70.0-101.0), 96.7 (92.4-101.1) (n = 14). Savolitinib alone or in combination was well tolerated. CONCLUSIONS: Co-dosing of rifampicin significantly reduced exposure to savolitinib vs savolitinib alone; co-dosing of itraconazole or midazolam with savolitinib had no clinically significant effect on savolitinib or midazolam PK, respectively. Co-dosing of famotidine with savolitinib reduced exposure to savolitinib, although this was not considered clinically meaningful. No new savolitinib-related safety findings were observed.

A Comprehensive Methodology to Systematically Identify Drug Hypersensitivity and Anaphylactic Reactions in Clinical Trial Databases.

BACKGROUND: The incidence of drug hypersensitivity or anaphylactic reactions in clinical trial databases is thought to be underestimated due to variable clinical presentations and lack of clear definitions. OBJECTIVE: Our objective was to develop a more comprehensive, systematic methodology for retrospectively identifying potential hypersensitivity or anaphylactic reactions reported in patients treated with investigational drugs in clinical trials and to accurately assess and characterise the risk. METHODS: A three-step approach was developed to identify hypersensitivity or anaphylactic reactions: clinical trial database search, medical review, and adjudication to confirm or rule out cases. The database search strategy consisted of the narrow search for Standardized MedDRA Query (SMQ) Hypersensitivity, a modified MedDRA query based on SMQ Anaphylactic reaction, and pyrexia-related MedDRA Preferred Terms. The cases identified from the search were further medically reviewed taking into consideration the temporal relationship, seriousness, severity, course, and management of the events, action taken, and outcomes of adverse events. Those cases deemed to have potentially drug-related hypersensitivity were then adjudicated to be confirmed or ruled out. RESULTS: The method was applied to a clinical trial database containing safety data for 421 patients treated with an investigational drug. Application of the methodology led to 19 hypersensitivity cases being identified. Of these, 12 were classified as immediate reactions and 7 as non-immediate reactions. CONCLUSION: This three-step method provided a thorough and robust way to identify hypersensitivity reactions, including anaphylaxis, in a clinical trial database. This method could be applied to investigational drugs to improve early detection and monitoring of potential safety concerns, subsequent patient safety management strategies, and potentially programme-wide drug development decisions. Algorithmic tools and narrow and/or broad SMQs should be considered when evaluating safety concerns. The authors also recommend a revision of the MedDRA SMQ of Anaphylactic reaction.