New paradigm for expediting drug development in Asia

Diversity in Oncology Clinical Trials: Current Landscape for Industry-Sponsored Clinical Trials in Asia

INTRODUCTION

There has been a growing recognition on the importance of diversity in clinical trials. Existing research has highlighted a significant demographic imbalance. Amidst this renewed focus on diversity, it is crucial to acknowledge that Asia comprises over half of the world's population. Given the region's demographic significance, we sought to compare various characteristics and growth rates for trials with sites in Asia against those without any sites in Asia.

METHODS

We performed comprehensive analyses of industry-sponsored phase 2 and 3 oncology trials registered at Clinicaltrials.gov, using drugs or biologics as investigational agents and executed between 1 January 2018 and 31 December 2022. We applied the compound annual growth rate (CAGR) as an analytical tool to track the trial growth rates over this 5-year period.

RESULTS

We identified 894 industry-sponsored phase 2 and 3 cancer studies with available study location data. Out of these, 415 trials (46.42%) had study sites in Asia. Notably, these trials with sites in Asia were also more likely to be phase 3 trials (39.76% vs 6.47%, p < 0.001), include female and paediatric populations, and be randomised trials. Interestingly, lung and stomach cancers were more commonly studied in these trials, while myeloma was less commonly studied. The number of trial sites for liver cancer was not significantly higher for Asia, even though the incidence of the disease is much higher in this region. Despite an overall declining trend in the number of clinical trials in the last 5 years, we observed a transitional positive increase in the CAGR from 2020 to 2021 for trials with sites in Asia. However, East Asia, specifically China, exhibited a disproportionate overrepresentation in these trials.

CONCLUSIONS

There are notable characteristics of clinical trials with sites in Asia. Comprehending these disparities may aid in the strategic planning to enhance a balanced representation of ethnicities in trials.

Comparison of the Incidence of Adverse Events Between Japanese and Non-Japanese Healthy Subjects in Phase I Studies: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Ethnic and racial differences are key factors affecting the results of clinical studies. However, the influence of these factors on the efficacy and safety of medicinal products remains unclear. Race-dependent nature is considered to be one of the factors causing differences in clinical findings, and we investigated its influence on the safety evaluation of drugs.

METHODS

We searched PubMed and a Japan drug approval list to find relevant studies, and extracted phase I studies conducted with Japanese and non-Japanese participants using the same protocol and at the same study site. Pooled estimates of odds ratios (ORs) for the incidence of major adverse events in Japanese and non-Japanese participants were calculated, using a DerSimonian-Laird method with a random-effects model.

RESULTS

Odds ratios for some adverse events in the active drug arm were significantly lower in Japanese participants: headaches [OR 0.65 (95% confidence interval [CI] 0.52-0.82), p = 0.0003], neurological disorders NEC [OR 0.70 (95% CI 0.53-0.93), p = 0.0135] in a High-Level Group Term, nervous system disorders [OR 0.64 (95% CI 0.49-0.82), p = 0.0004], infections and infestations [OR 0.71 (95% CI 0.53-0.95), p = 0.0202], and musculoskeletal and connective tissue disorders [OR 0.66 (95% CI 0.48-0.91, p = 0.0107] in the System Organ Class.

CONCLUSIONS

Our research suggested that racial factors such as race-dependent nature influence a drug safety assessment. With knowledge of these differences, it is expected that Japan will actively conduct multi-regional clinical trials, in which more diverse populations are included.

Model-based meta-analysis of ethnic differences and their variabilities in clearance of oral drugs classified by clearance mechanism

In this study, the ethnic ratios (ERs) of oral clearance between Japanese and Western populations were subjected to model-based meta-analysis (MBMA) for 81 drugs evaluated in 673 clinical studies. The drugs were classified into eight groups according to the clearance mechanism, and the ER for each group was inferred together with interindividual variability (IIV), interstudy variability (ISV), and inter-drug variability within a group (IDV) using the Markov chain Monte Carlo (MCMC) method. The ER, IIV, ISV, and IDV were dependent on the clearance mechanism, and, except for particular groups such as drugs metabolized by polymorphic enzymes or their clearance mechanism is not confirmative, the ethnic difference was found to be generally small. The IIV was well-matched across ethnicities, and the ISV was approximately half of the IIV as the coefficient of variation. To adequately assess ethnic differences in oral clearance without false detections, phase I studies should be designed with full consideration of the mechanism of clearance. This study suggests that the methodology of classifying drugs based on the mechanism that causes ethnic differences and performing MBMA with statistical techniques such as MCMC analysis is helpful for a rational understanding of ethnic differences and for strategic drug development.

Comparison of Pharmacokinetics of the GalNAc-Conjugated Antisense Oligonucleotide GSK3389404 in Participants with Chronic Hepatitis B Infection across the Asia-Pacific Region

GSK3389404, an N-acetyl galactosamine-conjugated antisense oligonucleotide (ASO), was in clinical development for chronic hepatitis B (CHB) treatment. Few studies have examined ASOs in Asian participants. In this analysis, the plasma pharmacokinetics (PK) of GSK3389404 were characterized and compared in patients with CHB across the Asia-Pacific region (N = 64), including mainland China (n = 16), Hong Kong (n = 8), Japan (n = 21), South Korea (n = 12), Singapore (n = 4), and the Philippines (n = 3), from a phase 2a, multicenter, randomized, double-blind, placebo-controlled study (NCT03020745). Hepatitis B(e) antigen-positive and -negative patients (on or not on stable nucleos[t]ide regimens) received single (30 mg or 120 mg) or multiple (30 mg, 60 mg, or 120 mg weekly or 120 mg biweekly) subcutaneous GSK3389404 injections. The plasma concentrations were measured on day 1 in all cohorts as well as on days 29 and 57 in the multiple-dose cohorts. The GSK3389404 plasma PK were similar to those reported in a previous study in non-Asian healthy participants with a median time to peak concentration (t_max) of 1 to 4 h postdose, a mean half-life of 3 to 5 h across cohorts, and no accumulation following repeat dosing. The GSK3389404 plasma t_max and half-life values were dose-independent. The increase in the plasma peak concentration (C_max) and the area under the concentration versus time curve (AUC) was dose-proportional from 60 to 120 mg and greater than dose-proportional from 30 to 60 or 120 mg. The GSK3389404 plasma concentration versus time profiles, half-life, t_max, C_max, and AUC values were all comparable across the Asia-Pacific populations. Given the similarity of the PK among ASOs, this analysis suggests that the PK from any Asia-Pacific population may be used to guide ASO dose selection in the Asia-Pacific region.

A physiologically based pharmacokinetic model of clopidogrel in populations of European and Japanese ancestry: An evaluation of CYP2C19 activity

Treatment response to clopidogrel is associated with CYP2C19 activity through the formation of the active H4 metabolite. The aims of this study were to develop a physiologically based pharmacokinetic (PBPK) model of clopidogrel and its metabolites for populations of European ancestry, to predict the pharmacokinetics in the Japanese population by CYP2C19 phenotype, and to investigate the effect of clinical and demographic factors. A PBPK model was developed and verified to describe the two metabolic pathways of clopidogrel (H4 metabolite, acyl glucuronide metabolite) for a population of European ancestry using plasma data from published studies. Subsequently, model predictions in the Japanese population were evaluated. The effects of CYP2C19 activity, fluvoxamine coadministration (CYP2C19 inhibitor), and population-specific factors (age, sex, BMI, body weight, cancer, hepatic, and renal dysfunction) on the pharmacokinetics of clopidogrel and its metabolites were then characterized. The predicted/observed ratios for clopidogrel and metabolite exposure parameters were acceptable (twofold acceptance criteria). For all CYP2C19 phenotypes, steady-state AUC0-τ of the H4 metabolite was lower for the Japanese (e.g., EM, 7.69 [6.26-9.45] ng·h/ml; geometric mean [95% CI]) than European (EM, 24.8 [20.4-30.1] ng·h/ml, p < .001) population. In addition to CYP2C19-poor metabolizer phenotype, fluvoxamine coadministration, hepatic, and renal dysfunction were found to reduce H4 metabolite but not acyl glucuronide metabolite concentrations. This is the first PBPK model describing the two major metabolic pathways of clopidogrel, which can be applied to populations of European and Japanese ancestry by CYP2C19 phenotype. The differences between the two populations appear to be determined primarily by the effect of varying CYP2C19 liver activity.

Phase I/Ib dose-escalation study of avelumab in Chinese patients with advanced solid tumors

Aim: Data for avelumab (anti-PD-L1 antibody) in Chinese patients are limited. Patients & methods: Phase I/Ib, open-label, dose-escalation study of Chinese patients with advanced solid tumors. Primary study objectives were to evaluate the maximum tolerated dose (MTD) and pharmacokinetics (PK) of avelumab. Results: 24 patients received avelumab 3 mg/kg every 2 weeks (Q2W; n = 3), 10 mg/kg Q2W (n = 7), 20 mg/kg Q2W (n = 6) or 10 mg/kg weekly for 12 weeks and then Q2W thereafter (n = 8). MTD was not reached. Avelumab exposure was increased in higher dose groups. Partial responses occurred in two patients (confirmed in one patient); best overall response was stable disease in nine patients. Conclusion: Data for avelumab in Chinese patients with advanced solid tumors were consistent with previous global studies.