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Japan firm starts clinical trial for next-gen. COVID-19 vaccine requiring smaller dosage

Wataru Akahata is shown in this image. (Mainichi/Momoko Suda)

TOKYO -- A drug discovery venture firm in Japan has begun its first phase of clinical trials for a new COVID-19 vaccine, it announced Oct. 18.

    The vaccine in development by VLP Therapeutics Japan uses new "replicon" technology, a next-generation messenger ribonucleic acid (mRNA) that self-replicates inside the recipient's body after vaccine administration. It reportedly requires a dosage of only 1/10 to 1/100 of the mRNA vaccines that have been put to practical use, and can be supplied in large quantities over a short time. The firm says it aims to apply for pharmaceutical approval and put it to practical use within 2022.

    While replicon vaccine clinical trials have begun in the United States and elsewhere, it is the first time they are being conducted in Japan. The replicon vaccine is a type of nucleic acid vaccine, like mRNA vaccines. But unlike Pfizer and other mRNA vaccines, the next-generation vaccine's replicon RNA self-replicates within cells for a limited period of time, thereby making it possible to induce immune responses even with a small dosage.

    In the first-stage clinical trial, the vaccine's safety and efficacy will be confirmed by administrating it twice each to some 45 adults aged 65 and under. The company intends to begin the final stages of clinical trials in spring 2022.

    Fujifilm Corp. will be in charge of manufacturing, and production of up to 50 million doses per year is the target for the time being. The Japanese government has also been supporting funds to develop the replicon vaccine.

    Wataru Akahata, head of VLP Therapeutics Japan, commented, "When new infectious diseases spread in future, this will serve as domestically-produced fundamental technology that allows us to react swiftly."

    (Japanese original by Ai Yokota, Lifestyle and Medical News Department)

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