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Phase I dose-escalation study of endoscopic intratumoral injection of OBP-301 (Telomelysin) with radiotherapy in oesophageal cancer patients unfit for standard treatments

2021; Elsevier BV; Volume: 153; Linguagem: Inglês

10.1016/j.ejca.2021.04.043

1879-0852

Yasuhiro Shirakawa, Hiroshi Tazawa, Shunsuke Tanabe, Nobuhiko Kanaya, Kazuhiro Noma, Takeshi Koujima, Hajime Kashima, Takuya Kato, Shinji Kuroda, Satoru Kikuchi, Shunsuke Kagawa, Kuniaki Katsui, Susumu Kanazawa, Yasuo Urata, Toshiyoshi Fujiwara,

CAR-T cell therapy research

Purpose OBP-301 (Telomelysin) is an attenuated type-5 adenovirus that contains the human telomerase reverse transcriptase promoter to regulate viral replication. OBP-301 sensitises human cancer cells to ionising radiation by inhibiting DNA repair, and radiation enhances coxsackievirus and adenovirus receptor–mediated OBP-301 infection on the contrary. We assessed OBP-301 with radiotherapy in oesophageal cancer patients unfit for standard chemoradiation treatments. Methods A phase I dose-escalation study of OBP-301 with radiotherapy was conducted in 13 histologically confirmed oesophageal cancer patients deemed unfit to undergo surgery or chemotherapy. Study treatment consisted of OBP-301 administration by intratumoural needle injection using a flexible endoscope on days 1, 18 and 32. Radiotherapy was administered concurrently over 6 weeks, beginning on day 4, to a total of 60 Gy. Results Of the 13 patients, 7, 3 and 3 patients were treated with 1010, 1011 and 1012 virus particles, respectively. Study group comprised 10 males and 3 females, with a median age of 82 years (range, 53–91 years). All patients developed a transient, self-limited lymphopenia. Distribution studies revealed transient virus shedding in the plasma. Eight patients had local complete response (CR); all of them exhibited no pathologically viable malignant cells in biopsy specimens, and 3 patients had a partial response. The objective response rate was 91.7%. The clinical CR rate was 83.3% in stage I and 60.0% in stage II/III. Histopathological examination revealed massive infiltration of CD8+ cells and increased PD-L1 expression. Conclusion Multiple courses of endoscopic intratumoural OBP-301 injection with radiotherapy are feasible and provide clinical benefits in patients with oesophageal cancer unfit for standard treatments.