Japan has granted marketing approval to Oncolys Biopharma’s oncolytic adenovirus Telomelysin (suratadenoturev, OBP-301) for treating esophageal cancer patients who are not eligible for curative resection or chemoradiotherapy. The approval marks the first oncolytic adenovirus product specifically approved for esophageal cancer in Japan. The regulatory action adds another oncology modality to the Japanese approval pipeline beyond conventional chemotherapies and targeted agents, reinforcing the role of oncolytic virus platforms in late-line or non-curative settings. For companies developing similar virotherapy approaches, the decision provides a reference point for what data packages regulators may accept when the therapeutic aim is to expand treatment options for patients with limited alternatives.