Sorrento Therapeutics Inc. (NASDAQ: SRNE) has announced that the US FDA has given the company clearance to go on with the phase 1b clinical trial utilizing STI-1386, Seprehvec entitled, “Dose Escalation Study of the Safety and Preliminary Efficacy of STI-1386 Oncolytic Virus in Patients with Relapsed or Refractory Solid Tumors.”
Seprehvec is a herpes simplex virus type 1
STI-1386, also known as Seprehvec, is a second-generation oncolytic herpes simplex virus type 1 (oHSV) developed after Sorrento acquired Virttu Biologics in 2017. It is manufactured in Sorrento’s GMP virus therapeutics production facility. Both RL1 gene copies are removed from the Seprehvec backbone, preventing expression of the neurovirulence factor ICP34.5 and restricting virus replication to rapidly dividing cells, such as tumor cells. Also, Seprehvec expresses transgenes encoding an anti-PD-1 scFv-Fc, interleukin-12, and a TGF beta receptor two decoys, which were all identified from the Sorrento G-MAB antibody library.
The transgene-encoded proteins secreted by Seprehvec-infected tumor cells are designed to work together to improve immune-mediated tumor destruction by inhibiting the PD-1/PDL-1 immune checkpoint pathway, reducing TGF beta’s immunosuppressive effects in the tumor microenvironment, and offering a localized IL-12 signal to attract and activate T and NK cells to the tumor.
Chief Medical Officer of Sorrento Mike Royal said 2Seprehvec allows for locoregional immune stimulation at the tumor site while potentially minimizing the undesired effects accompanying systemic immune stimulation. Our initial focus is to develop Seprehvec for treatment of sarcomas, pancreatic carcinomas, and hepatic metastases, with expansion to additional solid tumor indications in the future.”
Seprehvec simultaneously brings tumor killing and suppressing elements to solid tumors
SVP Antiviral and Oncolytic Immunotherapy Development Robert Allen commented, “Seprehvec provides a unique means of simultaneously bringing multiple tumor-killing and tumor-suppressing elements to bear on solid tumors, which are notoriously hard to eradicate. We are currently progressing additional oHSV candidates that mediate the recruitment and activation of anti-tumor responses from specific subsets of immune cells using this same approach. The virologists, cancer immunologists, and manufacturing scientists at Sorrento continue to leverage the breadth and quality of the G-MAB library, delivering best-in-class next-generation oHSVs, antibodies, and cellular immunotherapies to patients.”