Current Status of Single-Agent Phase I Trials in Japan: Toward Globalization

Performance of Japanese patients in registrational studies

INTRODUCTION

The accelerated development of lung cancer treatments has resulted in a single global study that is sufficient for a new agent and indication to be approved. Not all new treatments predominate globally, and differences in standards of care may influence the efficacy of treatments in the real world.

METHODS

The results from Japanese domestic trials and global trials that included a subset population of Japanese patients were evaluated for 18 genomic targeted agents and immune therapies approved after 2000. The results were collected from drug applications that were reviewed for treatment approval in Japan.

RESULTS

Japan is one of the first countries to approve and fully reimburse new agents around the world. Alectinib and nivolumab, which were first developed by Japanese pharmaceutical companies, were evaluated in an independent domestic trial, which resulted in their early approval. For most other indications, 1.1-15.8% of the patients who participated in pivotal registration studies were Japanese, and their treatment results were comparable to those of the overall population. Overall survival was less likely to be improved by four agents for which the post-protocol therapy might have been different in Japan than in other countries.

CONCLUSIONS

Overall, a positive result in a global trial was emulated in Japanese patients and led to the approval of a new standard treatment in Japan. Early approvals were attained by either participating in the global registrational study or conducting a domestic phase II study. The higher efficacy of new agents may be an issue in the future, as Japanese patients had early access to the new agent and may receive better treatment after the trial.

Clinical Utility of Next-Generation Sequencing-Based Panel Testing under the Universal Health-Care System in Japan: A Retrospective Analysis at a Single University Hospital

Next-generation sequencing (NGS) assay is part of routine care in Japan owing to its reimbursement by Japan's universal health-care system; however, reimbursement is limited to patients who finished standard treatment. We retrospectively investigated 221 patients who underwent Foundation One CDX (F1CDx) at our hospital. Every F1CDx result was assessed at the molecular tumor board (MTB) for treatment recommendation. Based on patients' preferences, presumed germline findings were also assessed at the MTB and disclosed at the clinic. In total, 204 patients underwent F1CDx and 195 patients completed the analysis; however, 13.8% of them could not receive the report due to disease progression. Among 168 patients who received the results, 41.6% had at least one actionable alteration, and 3.6% received genomically matched treatment. Presumed germline findings were nominated in 24 patients, and 16.7% of them contacted a geneticist counselor. The NGS assay should be performed earlier in the clinical course to maximize the clinical benefit. Broader reimbursement for the NGS assay would enhance the delivery of precision oncology to patients. Access to clinical trials affects the number of patients who benefit from NGS. Additionally, the disclosure of presumed germline findings is feasible in clinical practice.

Predictability of Severe Adverse Events in Phase 3 Trials from Safety Information on Phase 1 Trials in Oncology Drug Development

PURPOSE

Safety information obtained in phase 1 trials is becoming increasingly important with the recent changes in the development strategy of oncology drugs, including the skipping of phase 2 or 3 trials before regulatory approval. This study aimed to investigate the predictive factors for severe adverse events (AEs) in phase 3 trials based on phase 1 trial data.

METHODS

The data on phase 1 and phase 3 trials applied for their marketing approval of the newly approved anticancer drugs in Japan were used for analysis. Regression analyses were performed to investigate factors related to the predictability of the occurrence of severe AEs in phase 3 trials based on phase 1 trial data.

RESULTS

Thirty-two drugs (80 phase 1 trials and 40 phase 3 trials) were selected for the analyses. As a result of multivariate regression analyses, immune therapy agents (P = 0.009) and a pair of monotherapy in the phase 1 trials and combination therapy in the phase 3 trials (P = 0.017) were associated with low predictability of severe AEs in the phase 3 trials; signal inhibitor agents (P = 0.002) and large number of subjects in phase 1 trials (P = 0.008) were associated with high predictability. A significant relationship between the actual number of subjects in phase 1 trials and the predictability of severe AEs was observed when trials for immune checkpoint inhibitors were excluded (P < 0.001).

CONCLUSION

These results should be effectively utilized for the strategic design of early-stage oncology drug development.

Estimating Similarity of Dose-Response Relationships in Phase I Clinical Trials-Case Study in Bridging Data Package

Bridging studies are designed to fill the gap between two populations in terms of clinical trial data, such as toxicity, efficacy, comorbidities and doses. According to ICH-E5 guidelines, clinical data can be extrapolated from one region to another if dose–reponse curves are similar between two populations. For instance, in Japan, Phase I clinical trials are often repeated due to this physiological/metabolic paradigm: the maximum tolerated dose (MTD) for Japanese patients is assumed to be lower than that for Caucasian patients, but not necessarily for all molecules. Therefore, proposing a statistical tool evaluating the similarity between two populations dose–response curves is of most interest. The aim of our work is to propose several indicators to evaluate the distance and the similarity of dose–toxicity curves and MTD distributions at the end of some of the Phase I trials, conducted on two populations or regions. For this purpose, we extended and adapted the commensurability criterion, initially proposed by Ollier et al. (2019), in the setting of completed phase I clinical trials. We evaluated their performance using three synthetic sets, built as examples, and six case studies found in the literature. Visualization plots and guidelines on the way to interpret the results are proposed.

Improved survival among patients enrolled in oncology phase 1 trials in recent decades

PURPOSE

This study aimed to compare the survival of patients enrolled in phase 1 trials in recent decades.

METHODS

The medical records of consecutive patients with advanced cancer who participated in single-agent oncology phase 1 trials from 1995 to 2015 at a single institution were retrospectively investigated.

RESULTS

A total of 267 (34.1%) patients participated in 1995-2004 and 516 (65.9%) participated in 2005-2015. The median follow-up period was 25.4 months (range 1.3-166.9). The response rate did not differ significantly between the two periods (3.9% vs. 6.2%, p = 0.17). The median survival times were 9.5 (95% confidence interval 8.4-11.2) months in 1995-2004 and 11.8 (95% confidence interval 10.9-13.3) months in 2005-2015 (p = 0.0009). The enrolment period was an independent prognostic factor of overall survival according to multivariate analysis (hazard ratio: 0.85, 95% confidence interval 0.72-0.99, p = 0.042).

CONCLUSIONS

In our single-centre, retrospective analysis, the trends in patients characteristic were consistent with those of Western countries, and the overall survival of cancer patients enrolled in oncology phase 1 trials tended to improve in recent decades, suggesting that patient selection, the population that benefits from investigational agents and treatment after phase 1 trials have improved.

Do all patients in the phase I oncology trials need to be hospitalized? Domestic but outstanding issues for globalization of drug development in Japan

INTRODUCTION

Most trials investigating new drugs around the world, including phase I trials, are conducted in outpatient clinics. However, in Japan, regulatory authority requirements and traditional domestic guidelines often require hospitalization of phase I study participants.

PATIENTS AND METHODS

Patients participating in single-agent phase I clinical trials at National Cancer Center Hospital between December 1996 and August 2014 were monitored. Toxicity requiring hospitalization is defined as toxicity that needs intensive treatment. Study designs were classified into three types: first-in-human (FIH) study, dose-escalation study (conventional dose-escalation study to determine maximum tolerated dose (MTD) in Japanese patients), and dose-finding study (to assess safety and pharmacokinetic profiles up to the MTD previously determined in the West).

RESULTS

A total of 945 patients who participated in a variety of single-agent phase I clinical trials between December 1996 and August 2014 were included in this study. Patients participated in one of three study types: dose-escalation (n = 582, 62%), first-in-human (n = 129, 14%), or dose-finding (n = 234, 25%). A total of 76 study drugs were evaluated as part of this pool of phase I studies. Subdivided by mechanism of action, 20 (26%) were cytotoxic, 50 (66%) were molecularly targeted, and 6 (8%) were immune checkpoint inhibitor. Thirty-six patients (3.8%) had severe toxicities requiring hospitalization during the first cycle. The overall number of toxicities requiring hospitalization and/or grade 4 toxicities during any cycle was 5.0%.

CONCLUSIONS

The frequency of severe toxicity that needs to be hospitalized was unexpectedly low. The data did not demonstrate the need for hospitalization in the phase I trials, suggesting that phase I trials in Japan could be conducted in outpatient settings.

Phase I dose-finding study of monotherapy with atezolizumab, an engineered immunoglobulin monoclonal antibody targeting PD-L1, in Japanese patients with advanced solid tumors

Background Atezolizumab is an engineered immunoglobulin monoclonal antibody that targets the programmed death-1/programmed death-ligand 1 pathway. Methods In this phase I dose-finding study, we assessed the safety, feasibility, pharmacokinetics (PK), and exploratory anti-tumor activity of atezolizumab monotherapy up to 20 mg/kg in Japanese patients with advanced solid tumors who had failed standard therapy or for whom there is no standard therapy. Results Six patients were enrolled and received intravenous atezolizumab every 3 weeks (q3w) at doses of 10 or 20 mg/kg. Tumor types were non-small cell lung cancer (n = 3), melanoma (n = 1), pancreatic cancer (n = 1), and thymic cancer (n = 1). No dose-limiting toxicities were observed. All adverse events (AEs) were grade 1 or 2 in severity. No discontinuations or deaths due to AEs were observed. As of the data cutoff, no partial responses were observed; however, stable disease was observed in all six patients. The maximum mean serum atezolizumab concentration was 220 μg/mL (SD ± 21.9), with 10-mg/kg dosing and 536 μg/mL (SD ± 49.4) with 20-mg/kg dosing. Three patients were still on treatment, and three of the six had achieved a progression-free survival of >12 months. Conclusions Atezolizumab was well tolerated in Japanese patients at doses up to 20 mg/kg q3w. The safety profile and Cycle 1 serum atezolizumab concentrations were similar to those previously observed in non-Japanese patients. These data support the participation of Japanese patients in ongoing pivotal global studies of atezolizumab.