Pharmacokinetics (PK) of Tiragolumab in First-in-Human Study in Patients with Mixed Solid Tumors (GO30103)

Cross validation of pharmacokinetic bioanalytical methods: Experimental and statistical design

Pharmacokinetic (PK) analysis is an integral part of drug development. Health agency guidance provides development and validation recommendations for PK bioanalytical methods run in one laboratory. However, as a drug development program progresses, a PK bioanalytical method may need to be run in more than one laboratory. Additionally, a PK bioanalytical method format may change and a new method platform may be validated and implemented during the drug development cycle. Here we describe the cross validation strategy for comparisons of two validated bioanalytical methods used to generate PK data within the same study or across different studies. Current guidance for cross validations is limited and, therefore, Genentech, Inc. has developed a cross validation experimental strategy that utilizes incurred samples along with a comprehensive statistical analysis. One hundred incurred study samples over the applicable range of concentrations are selected based on four quartiles (Q) of in-study concentration levels. The samples are assayed once in the two bioanalytical methods. Bioanalytical method equivalency is assessed for the 100 samples based on pre-specified acceptability criterion: the two methods are considered equivalent if the percent differences in the lower and upper bound limits of the 90 % confidence interval (CI) are both within ±30 %. Quartile by concentration analysis using the same criterion may also need to be performed. A Bland-Altman plot of the percent difference of sample concentrations versus the mean concentration of each sample is also created to help further characterize the data. This strategy is a robust assessment of PK bioanalytical method equivalency and includes subgroup analyses by concentration to assess for biases. This strategy was implemented in two case studies: 1) two different laboratories using the same bioanalytical method and 2) a bioanalytical method platform change from enzyme-linked immunosorbent assay (ELISA) to multiplexing immunoaffinity (IA) liquid chromatography tandem mass spectrometry (IA LC-MS/MS).

Phase I pharmacokinetic, safety, and preliminary efficacy study of tiragolumab in combination with atezolizumab in Chinese patients with advanced solid tumors

PURPOSE

Tiragolumab is an immunoglobulin G1 monoclonal antibody targeting the immune checkpoint T cell immunoreceptor with immunoglobulin and immunoreceptor ITIM domains. Targeting multiple immune pathways may improve anti-tumor responses. The phase I YP42514 study assessed the pharmacokinetics (PK), safety, and preliminary efficacy of tiragolumab plus atezolizumab in Chinese patients with advanced solid tumors.

METHODS

Adult patients from mainland China with Eastern Cooperative Oncology Group performance score 0/1, life expectancy of ≥ 12 weeks, and adequate hematologic/end organ function were eligible. Patients received tiragolumab 600 mg and atezolizumab 1200 mg intravenous every 3 weeks. Key endpoints were PK (serum concentrations of tiragolumab and atezolizumab) and safety. Results from this study were compared with the global phase I study, GO30103 (NCT02794571).

RESULTS

In this study, 20 patients received a median of five doses of tiragolumab plus atezolizumab. Median age was 57.5 years, 85.0% of patients were male and the most common tumor type was non-small cell lung cancer. Exposures in Chinese patients were comparable to the global GO30103 population: geometric mean ratio was 1.07 for Cycle 1 tiragolumab area under the concentration-time curve0-21 and 0.92 and 0.93 for Cycle 1 peak and trough atezolizumab exposure, respectively. Treatment-related adverse events were consistent across the Chinese and global populations. Two patients (10.0%) in this study achieved a partial response.

CONCLUSION

In this study, tiragolumab plus atezolizumab was tolerable and demonstrated preliminary anti-tumor activity. There were no meaningful differences in the PK or safety of tiragolumab plus atezolizumab between the Chinese and global populations.

CLINICAL TRIAL REGISTRATION NUMBER

China Clinical Trial Registry Identifier CTR20210219/YP42514. Date of registration 16 March 2021.

Implementation of a Three-Way Comparability Assessment for a Bioanalytical Anti-Drug Antibody Method

Immunogenicity evaluation is a critical part of drug development. Regulatory guidelines from multiple health agencies provide recommendations for the development and validation of anti-drug antibody (ADA) assays to assess immunogenicity in clinical trials. These recommendations primarily describe an ADA method run in one bioanalytical laboratory supporting a biotherapeutic molecule; however, there are increasing instances that may necessitate the support of the ADA method being run in more than one laboratory. A program can rapidly expand into multiple clinical studies within one or multiple countries, where the most appropriate way to support the program is by having multiple laboratories perform ADA sample analysis. In addition, there may be certain country-specific challenges that may make it infeasible to transport samples outside of the country for analysis. China for example has a lengthy sample exportation process that has potential to negatively impact study timelines. If multiple laboratories analyze samples using the same ADA method, comparable method performance should be established. Here, we describe a three-way assessment of ADA assay comparability between two US-based bioanalytical laboratories and one based in China.