Oncolytic Virus Teserpaturev Approved in Japan for Malignant Glioma

The Japan Ministry of Health, Labour, and Welfare has granted conditional and time-limited approval to teserpaturev (G47∆; Delytact) for the treatment of patients with malignant glioma; this is the first oncolytic virus to receive approval for use in this indication or any primary brain cancer.¹

The regulatory decision was supported by findings from a single-arm phase 2 trial, which had met its primary end point of 1-year survival rate in an interim analysis.

Data from the research is anticipated to be submitted by Tomoki Todo, MD, professor at the Institute of Medical Science of the University of Tokyo, and colleagues. Daiichi Sankyo has been collaboratively developing the oncolytic virus with Todo, who is the marketing authorization holder of the produce in Japan.

“With the approval of [teserpaturev] in Japan, we can now offer the first-ever oncolytic virus therapy option to patients with glioblastoma and other malignant gliomas that are not controlled with currently available treatments,” Wataru Takasaki, PhD, executive officer, head of the R&D Division in Japan, at Daiichi Sankyo, stated in a press release.

Oncolytic viruses can be genetically engineered or naturally occur, and they are capable of selectively replicating in, and eliminating, cancer cells without harming normal tissues.² This therapeutic approach differs from gene therapy in that it uses the virus itself as an active drug reagent.

Teserpaturev is a triple-mutated, third-generation oncolytic herpes simplex virus type 1 that was developed to strengthen antitumor activity and preserve safety of the G207 genome. The product is able to do this because it enhances the ability to induce specific antitumor immunity.

Previously, tesperpaturev has demonstrated a stronger replication ability with higher antitumor activity than G207. The product showed efficacy in all in vivo solid tumor models that had been evaluated, which included glioma, breast cancer, prostate cancer, schwannoma, nasopharyngeal carcinoma, hepatocellular carcinoma, colorectal cancer, malignant peripheral nerve sheath tumor, and thyroid carcinoma. The product has also effectively eliminated human glioblastoma–derived cancer stem cells.

The novel therapy is the first of its kind to be investigated in humans as part of a phase 1-3a study in Japan; the agent was specifically evaluated in patients with recurrent glioblastoma. The trial had completed in 2014, and the phase 2 trial was launched in 2015. In the phase 2 trial, investigators set out to evaluate tesperpaturev in patients with residual or recurrent glioblastoma (UMIN000015995).

Here, participants were administered a stereotactic injection of the oncolytic virus at a dose of 1 × 109 pfu into the brain twice weekly followed by every 4 weeks for a maximum of 6 doses.

In February 2016, the product was granted a “Sakigake” breakthrough therapy designation, which allows for the agent to undergo early examination and priority review by the Pharmaceutical and Medical Devices Agency of Japan to put the product on a “fast track” for approval. The following year, in 2017, teserpaturev was also granted an orphan drug designation.

Beyond glioblastoma, the product has also been evaluated in patients with castration-resistant prostate cancer, as part of a single-arm, phase 1 trial (UMIN000010463). Participants were given the therapy via an injection of 3 × 108 pfu into the prostate through a transrectal ultrasound-guided transperineal strategy.

The trial was comprised of 3 patient cohorts: cohort 1 received the product twice, cohort 2 received it 3 times, and cohort 4 received it 4 times.

Results indicated that the oncolytic virus was well tolerated, with no severe adverse effects experienced.

“[Teserpaturev] is the fourth oncology medicine to be approved in Japan for Daiichi Sankyo over the past 2 years and we are grateful for the opportunity to collaborate with Dr Todo to deliver this truly innovative treatment modality to patients and physicians in Japan,” Takasaki added.

Teserpaturev is now under examination in patients with recurrent olfactory neuroblastoma, as part of another phase 1 trial (UMIN000011636).

References

1. DELYTACT oncolytic virus G47∆ approved in Japan for treatment of patients with malignant glioma. News release. Daiichi Sankyo Company, Limited. June 11, 2021. Accessed June 11, 2021. https://bit.ly/3cxBCSE
2. Fukuhara H, Ino Y, Todo T, et al. Oncolytic virus therapy: a new era of cancer treatment at dawn. Cancer Sci. 2016;107(10):1373-1379. doi:10.1111/cas.13027