Telomelysin (OBP-301)


Telomelysin is a gene-modified oncolytic adenovirus in which selectively replicate in cancer cells by introducing human telomerase reverse transcriptase (hTERT) promotor. Oncolytic adenovirus has much potential for cancer immunotherapy because its viral replication is highly immunogenic, and oncolysis induced by such virus releases tumor antigen and provides costimulatory danger signals. From the result of phase 1 clinical study in the US, OBP-301 showed abscopal effect, which non-injected tumor as well as injected tumor was regressed in melanoma patients after single injection into one single tumor and found that not only increasing infiltration of CD8 and antigen presenting cells but diminishing Treg cells in injected tumor site.
Oncolys has been conducting phase 1 clinical study of Telomelysin monotherapy for hepatocellular carcinoma in Korea and Taiwan and a phase 1 clinical study in combination with radiation for esophageal cancer in Japan. The latter will be conducted by Chugai Pharmaceutical from phase 2 onward, based on the exclusive license agreement concluded between two parties on 8 April, 2019. In addition, an investigator-led phase 2 clinical trial for Telomelysin-checkpoint inhibitor combination therapy for gastric and GEJ cancer has been ongoing in the US. We will also soon initiate investigator-led phase 2 study for head and neck cancer for Telomelysin-checkpoint inhibitor combination therapy in the US.


Target indication

Gastrointestinal cancers (esophageal cancer, gastric cancer, etc.), head and neck cancer, and hepatocellular carcinoma

Current status

In preclinical studies for Telomelysin, Oncolys has demonstrated effective anti-tumor activity on various cancer cells, and there was no finding that may bring safety concerns in toxicological studies as well as bio-distribution study. Oncolys completed the phase 1 clinical trial for solid tumors in the US with 16 subjects for single dosing and 6 subjects for repeated dosing. Most of the adverse events observed in the study was mild to moderate and transient, and there was a sign of efficacy showing tumor shrinkage in 8 out of 12 evaluable patients.
In Japan, investigator initiated clinical research for esophageal cancer in combination with radiotherapy was conducted in Okayama University. The research, completed in 2018, resulted that 8 out of 13 patients showed CR (complete response), and CD8 T cell infiltration was observed in tumor area. Based on such positive data, Oncolys started a phase 1 study in 2017, which is expected to be completed by the end of 2019 and a Japanese pharmaceutical company Chugai Pharmaceutical will lead the study from the phase 2 onward, based on the exclusive license agreement for Telomelysin concluded between Chugai and Oncolys on 8 April, 2019.
In addition, Oncolys has an ongoing phase 1 clinical trial of Telomelysin monotherapy targeting hepatocellular carcinoma patients refractory to existing cancer treatments in Korea and Taiwan under the IND approved by the US FDA, which is collaboratively conducted with Taiwanese listed biotech company, Medigen Biotechnology Corp. 18 patients in total (single dosing cohorts 1 to 4; 3 patients in each cohort, multiple dosing cohort 5; 6 patients) have been enrolled to date and no serious adverse event has been observed.
We further have two clinical studies in the US. One is an investigator-led gastric and gastroesophageal junction cancer phase 2 study in combination with an anti-PD-1 antibody Pembrolizumab. It has been ongoing since early 2019 and up to 37 patients are expected to be enrolled in this study. The other one is head and neck cancer phase 2 study in combination with a check-point inhibitor, which we anticipate its launch in the near future.

  • (Countries where patent was issued)
  • Japan, United States, Europe, South Africa, Singapore, New Zealand, Australia, China, Hong Kong,
    South Korea, Canada.

Telomelysin & Current Development Status

Clinical Trials


Preclinical studies and proof of concept

Clinical Development Strategy and Program