Utility of Biomarker-Informed Drug Interaction Evaluation in Drug Development and Regulatory Decision Making.

The measurement of endogenous biomarkers in plasma and urine before and after administration of an investigational drug in a clinical study may provide an early indication of its drug-drug interaction (DDI) potential via a specific pathway. In the first international harmonized guideline on drug interaction studies, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) M12, endogenous biomarkers have been recognized as an emerging approach in the transporter- and enzyme-based DDI risk assessment. Clinical Pharmacology Roundtable Conference 2024 held at Pharmaceuticals and Medical Devices Agency (PMDA) brought together experts from regulatory agencies, academia, and industries to discuss potential advantages and challenges of the biomarkers approach in drug development and regulatory decision making.

Malignant melanoma treatment using brachytherapy: Two case reports and 15 case series.

Malignant melanoma (MM) is usually resistant to radiotherapy. Brachytherapy may be an option in patients with bleeding or pain, and those in whom surgery is difficult. Brachytherapy has few side effects and can be used in combination with external beam radiotherapy or chemotherapy.

Type 1 diabetes associated with immune checkpoint inhibitors for malignant melanoma: A case report and review of 8 cases.

Advanced malignant melanoma (MM) is treated with immune checkpoint inhibitor (ICI) therapy, which often results in several immune-related adverse events. Fulminant type 1 diabetes mellitus (T1DM) is a rare, rapidly progressive, life-threatening disease. Here, we summarize 8 cases of MM with ICI-induced T1DM and describe one case that developed fulminant T1DM due to nivolumab therapy.

Classification of drugs for evaluating drug interaction in drug development and clinical management.

During new drug development, clinical drug interaction studies are carried out in accordance with the mechanism of potential drug interactions evaluated by in vitro studies. The obtained information should be provided efficiently to medical experts through package inserts and various information materials after the drug's launch. A recently updated Japanese guideline presents general procedures that are considered scientifically valid at the present moment.

Evolving Acceptance and Use of RWE for Regulatory Decision Making on the Benefit/Risk Assessment of a Drug in Japan.

There is growing interest in the utilization of real-world data (RWD) and real-world evidence (RWE) for regulatory purposes. However, there are challenges in the practical utilization of RWD to provide RWE as a basis for regulatory decision making. This article presents the regulatory initiatives in Japan and efforts taken to promote the utilization of RWD/RWE for regulatory decision making at the pre- and postapproval stages of a drug.

Designation Products: Boron Neutron Capture Therapy for Head and Neck Carcinoma.

The Japanese Ministry of Health, Labour and Welfare approved a drug called borofalan ( B), a treatment system, and a dose calculation program for boron neutron capture therapy (BNCT) in March 2020. The application pertaining to the products submitted to the Pharmaceuticals and Medical Devices Agency was supported by a Japanese, open-label, uncontrolled trial (Study 002) in patients with unresectable, locally recurrent head and neck squamous cell carcinoma after chemoradiotherapy or radiotherapy, or in those with unresectable locally advanced or locally recurrent (LA/LR) head and neck nonsquamous cell carcinoma. The drug was administered as a single intravenous dose using infusion rates of 200 mg/kg per hour for the first 2 hours after the start of administration and 100 mg/kg per hour during irradiation.

A case of drug-induced Stevens-Johnson syndrome-like eruption predominating in mucosa: A case report.

Atypical Stevens-Johnson syndrome (SJS) is a variant of SJS with complete absence of or only few cutaneous manifestations. It usually affects children with Mycoplasma-induced respiratory infection. It was unique because our case was induced by drug and occurred in an adult.

Development of a new Japanese guideline on drug interaction for drug development and appropriate provision of information.

Drug interactions, in particular with concomitant drugs having a narrow therapeutic range, sometimes cause serious adverse drug reactions or attenuation of the therapeutic effect. Therefore, evaluation of the characteristics and severities of possible drug interactions in drug development is essential to understand such interactions to help prevent any potential risk for patients. In Japan, a regulatory document which was notified in 2001 to outline the basic principles of drug interaction studies during drug development was revised as a new guideline after 17 years to present general procedures that are currently considered scientifically valid.

[Current PMDA Activities for Use of Biomarkers in Drug Evaluation].

Biomarkers (BM) are gradually being recognized as useful tools to evaluate drugs from development through post-approval periods. In the past decade, practical use of BM has advanced particularly in the field of anti-cancer drug development. Regardless of the use of BM, approximately 10% of key clinical trials for new drug applications of anti-cancer drugs were conducted as multiregional clinical trials.

Characteristics of pharmacogenomics/biomarker-guided clinical trials for regulatory approval of anti-cancer drugs in Japan.

Pharmacogenomics (PGx) or biomarker (BM) has the potential to facilitate the development of safer and more effective drugs in terms of their benefit/risk profiles by stratifying population into categories such as responders/non-responders and high-/low-risks to drug-induced serious adverse reactions. In the past decade, practical use of PGx or BM has advanced the field of anti-cancer drug development. To identify the characteristics of the PGx/BM-guided clinical trials for regulatory approval of anti-cancer drugs in Japan, we collected information on design features of 'key trials' in the review reports of anti-cancer drugs that were approved after the implementation of the 'Revised Guideline for the Clinical Evaluation of Anti-cancer drugs' in April 2006.

Regulatory perspective on remaining challenges for utilization of pharmacogenomics-guided drug developments.

Pharmacogenomics-guided drug development has been implemented in practice in the last decade, resulting in increased labeling of drugs with pharmacogenomic information. However, there are still many challenges remaining in utilizing this process. Here, we describe such remaining challenges from the regulatory perspective, specifically focusing on sample collection, biomarker qualification, ethnic factors, codevelopment of companion diagnostics and means to provide drugs for off-target patients.

Prediction of severe adverse drug reactions using pharmacogenetic biomarkers.

Severe adverse drug reactions (ADRs) are a major issue for drug therapy because they can cause serious disorders and be life-threatening. Many severe ADRs appear to be idiosyncratic and unpredictable. Genetic factors may underlie susceptibility to severe ADRs, and identification of predisposing genotypes may improve drug therapy by facilitating prescreening of carriers for specific genetic biomarkers.

Current Japanese regulatory situations of pharmacogenomics in drug administration.

Pharmacogenomics (PGx) has the potential impact to improve drug-development efficiencies and proper usages of drugs in clinical practice. However, in order to translate PGx into practical applications, multidisciplinary challenges, such as cost and time in development, processes of genomic biomarker qualification, PGx test availabilities and reimbursements, and education on PGx, still remain in clinical, pharmaceutical and regulatory settings. Japanese regulatory bodies for drug approval (i.

High-throughput detection of multiple genetic polymorphisms influencing drug metabolism with mismatch primers in allele-specific polymerase chain reaction.

Because of genetic polymorphisms of drug-metabolizing enzyme genes, the activities of the enzymes in humans vary widely and alter the metabolism of commonly used clinical agents. Severe adverse effects or resistance to therapy may result. We have developed a rapid and high-throughput genotyping method for detecting polymorphisms of the drug-metabolizing enzyme genes CYP2C9*3, CYP2C19*2, *3, CYP2D6*2, *4, *10, *14, *21, NAT2*5, *6, *7, and TPMT*3 using allele-specific polymerase chain reaction (PCR) with mismatch primers (ASPCR-MP) and CYP2D6*5, *36, and CYP2D6xN using stepdown PCR with detection by SYBR Green I.

A long PCR assay to distinguish CYP2D6*5 and a novel CYP2D6 mutant allele associated with an 11-kb EcoRI haplotype.

Background: We found a genomic DNA (N=1) associated with an unidentified 11-kb EcoRI haplotype of CYP2D6 and with amplification of the CYP2D6*5 specific polymerase chain reaction (PCR) product without the 11.5-kb XbaI haplotype in a Japanese woman. We developed a long PCR assay to distinguish CYP2D6*5 and the novel mutant allele, and we evaluated the PCR method on 162 different genomic DNA samples.

Metabolic activity of dextromethorphan O-demethylation in healthy Japanese volunteers carrying duplicated CYP2D6 genes: duplicated allele of CYP2D6*10 does not increase CYP2D6 metabolic activity.

Background: This study was designed to assess the metabolic activities of dextromethorphan O-demethylation in healthy Japanese subjects carrying duplicated CYP2D6 alleles, CYP2D6*1 x 2, CYP2D6*2 x 2 or CYP2D6*10 x 2.

Methods: Forty-one unrelated healthy Japanese subjects containing carriers who had previously been genotyped as CYP2D6*1 x 2/*2, CYP2D6*1/*2 x 2, and CYP2D6*10/*10 x 2 were phenotyped with dextromethorphan.

Results: The metabolic ratios of dextromethorphan/dextrorphan in subjects with CYP2D6*1 x 2/*2 or CYP2D6*1/*2 x 2 were lower than those in subjects with CYP2D6*1/*2, while the metabolic ratios in subjects with CYP2D6*10/*10 x 2, as well as homozygotes for CYP2D6*10, were significantly (P<0.

Frequent occurrence of CYP2D6*10 duplication allele in a Japanese population.

Allele-specific long-polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism (RFLP) and haplotype analysis using XbaI and EcoRI were used to determine whether gene duplication of CYP2D6*10 exists in a Japanese population of 162 healthy subjects. Based on the results of PCR and haplotype analysis, the frequencies of CYP2D6*1X2, CYP2D6*2X2 and CYP2D6*10X2 in the Japanese population were estimated to be 0.3, 0.