Over the last several months, Sorrento Therapeutics, Inc. and its development partners have advanced into clinical development (Phase 1b through Phase 3 clinical trials) a number of fully human monoclonal antibodies (mAbs) for the treatment of COVID-19 and various cancers. This demonstrates the potential of the deep pipeline generated from Sorrento’s proprietary G-MAB™ library, invented by Dr. Henry Ji, the Chairman and CEO of Sorrento. This G-MAB library is based on the use of RNA transcription for amplification of the antibody variable domains from over 600 donors. These donors were from both sexes and of multiple ethnicities, leading to a broad diversity of antibodies. In-depth analysis of deep sequencing DNA data showed that the G-MAB library contains more than 20 quadrillion (1016) distinct antibody sequences. The G-MAB library has fostered the development of several early and late-stage oncology programs that are currently in Phase 2 and Phase 3 clinical trials and neutralizing mAbs currently in a Phase 2 clinical trial directed against the spike protein of COVID-19 viruses.
Two independent anti-PD-L1 mAbs are now in Phase 2 and Phase 3 clinical studies. A PD-L1 mAb (STI-3031, also known as IMC-001) was licensed to ImmuneOncia Therapeutics, Inc. (“ImmuneOncia”), a joint venture between Sorrento and Seoul-based Yuhan Corporation. IMC-001 has completed a Phase 1b study in patients with metastatic or locally-advanced solid tumors and is nearing completion of a Phase 2, open-label, “Neo-Chance” study in patients with resectable gastric cancer, esophageal cancer and liver cancer. ImmuneOncia has also started to enroll patients in a Phase 2 study in relapsed or refractory extranodal NK/T cell lymphoma, nasal type. Sorrento has filed an IND in the U.S. and received clearance from the FDA to proceed with a Phase 2a study for STI-3031 for advanced urothelial carcinoma.
A second antibody, Socazolimab, is licensed to Lee’s Pharmaceutical Holdings Limited in the Greater China territory, and has been cleared to begin a multicenter Phase 3 trial as a potential first-line treatment for patients with extensive-stage small-cell lung cancer. Professor Shun Lu (Shanghai Chest Hospital) is the Principal Investigator. Additionally, Phase 1b studies in several other indications have been completed for this product candidate, including: recurrent metastatic cervical cancer, advanced urothelial carcinoma, and high-grade osteosarcoma after adjuvant chemotherapy for maintenance. In addition, a Phase 1b/2 study has been initiated as a potential neoadjuvant treatment option for esophageal carcinoma. For cervical cancer, a pivotal study has been completed with a breakthrough therapy designation granted by the National Medical Products Administration (NMPA) in China. Sorrento intends to open an IND in the U.S. with the intent to have an end-of-phase 3 meeting or pre-NDA discussion with the FDA for various cancer indications.
Sorrento previously announced FDA clearance to commence a Phase 1b study in various relapsed or refractory solid tumors with an anti-CD47 antibody (STI-6643) (a CD-47 checkpoint inhibitor interacting with SIRPα). In preclinical studies, STI-6643 appears to have a beneficial toxicity profile (e.g., reduced hemolysis) without a priming mechanism while maintaining potent anti-tumor activity. Additionally, Sorrento licensed a separate promising anti-CD47 antibody (IMC-002) to ImmuneOncia, which has initiated a Phase 1b study in patients with metastatic or locally-advanced solid tumors and relapsed or refractory lymphomas.
Sorrento previously announced the formation of its subsidiary company - Adnab, Inc.,– which is focused on developing and commercializing ADNAB platform products for hematological malignancies and solid tumors based on an exclusive license from the Mayo Clinic. Sorrento intends to combine a variety of its proprietary mAbs in conjunction with the ADNAB technology platform, which was developed by Dr. Svetomir Markovic, M.D., Ph.D., and his research team at Mayo Clinic. This effort will potentially result in multiple next-generation ADNAB products. Since ADNABs can be designed to have one or two mAbs on the external surface, in addition to a chemotherapeutic payload, the cytotoxic payload can potentially be delivered preferentially to targeted cancer cell types. Sorrento expects to develop a number of innovative ADNABs in anticipation of filing INDs for clinical trials later in 2021.
“These are very exciting times for Sorrento,” said Dr. Ji. “These therapeutic antibody examples demonstrate that we are leveraging the G-MAB library to bring product candidates rapidly from preclinical development through the IND process and into clinic trials.”