Sorrento Announces First Patient Treated in Phase IB AL Amyloidosis Trial with STI-6129, an Anti-CD38 Antibody-Drug Conjugate

• STI-6129 is an antibody-drug conjugate (ADC) composed of a fully human monoclonal anti-CD38 antibody covalently bound by a proprietary chemical linker to a duostatin tubulin inhibitor.
  
• Amyloid Light Chain (AL) Amyloidosis is an incurable disease with limited treatment options and the potential for the development of resistance to current approaches.
  

SAN DIEGO, March 18, 2021 (GLOBE NEWSWIRE) -- Sorrento Therapeutics, Inc. (Nasdaq: SRNE, "Sorrento") today announced that the first patient has been treated in its Phase 1b Amyloid Light Chain (AL) Amyloidosis study of STI-6129, an ADC which uses STI-5171, a fully human monoclonal antibody (mAb) from Sorrento’s G-MAB library. This study is being conducted as a multicenter, open-label, dose-escalation clinical trial in patients with advanced relapsed and/or refractory systemic amyloid light chain (AL) amyloidosis with a primary objective to identify a Phase 2 dose for STI-6129 based on its safety, preliminary efficacy and pharmacokinetic profile.

STI-6129 is an ADC with covalently bound duostatin tubulin inhibitors (Duostatin 5) using a proprietary site-specific C-LOCK chemical linker designed to reduce the premature systemic release of duostatin and avoid the potential for toxicity, particular ocular toxicity, seen with other ADCs, especially first-generation products. STI-6129 has demonstrated an improved therapeutic index in animal models, as compared to traditional non-selective conjugates. STI-6129 has the potential for being a first-line treatment for amyloidosis as well as second line in those patients who have developed daratumumab resistance, an anti-CD38 mAb alone. STI-6129 binds to different epitopes than daratumumab and the addition of the targeted delivery of the duostatin can potentially manage those patients who have become refractory to such treatments.

“Enrollment into our amyloidosis study with STI-6129 is another important milestone for Sorrento, and although delayed due to COVID-19, we are pleased this study has started,” stated Dr. Henry Ji, Chairman and CEO of Sorrento Therapeutics. “Together with our CD38 CAR-T and DAR-T programs, STI-6129 has the potential to provide additional therapeutic options for patients in need and we are excited to see how it performs in treating patients with AL amyloidosis. We also are looking forward to further evaluating the safety and efficacy of STI-6129 in a soon to start refractory or relapsing multiple myeloma clinical trial.”