Sorrento Therapeutics, Inc. announced that its partner, MabTech Ltd. has successfully completed Phase 3 clinical trials in China for STI-001, a biosimilar/biobetter antibody for Cetuximab (Erbitux®) and STI-002, a biosimilar/biobetter antibody for Infliximab (Remicade®). Both STI-001 and STI-002 met their primary endpoints in confirmatory, randomized, controlled, two-part Phase 3 studies. STI-001, a chimeric monoclonal antibody that binds to the epidermal growth factor receptor (EGFR) was used for treatment of EGFR-expressing metastatic colorectal carcinoma patients in combination with irinotecan versus irinotecan alone.

The combination therapy showed significant improvement compared to chemotherapy alone in Overall Response Rate (ORR: 32.9% vs 12.8%) and Progress-free Survival (PFS: 5.6 vs 3.2 months) as well as longer Overall Survival (OS: 14.1 vs 13.4 months). The ORR, PFS and OS using STI-001 and irinotecan are increased significantly than previously reported in similar medical settings using Erbitux and irinotecan (32.9% vs 10%; 5.6 vs 4.0 months; 14.1 vs11.6 months). STI-002, a chimeric monoclonal antibody produced in CHO cell line binds to soluble and transmembrane forms of tumor necrosis factor ± (TNF±) and inhibits TNF± binding to receptors thereby neutralizing the biological activity of TNF±.

In the current Phase 3 study with 330 patients conducted in China for the treatment of rheumatoid arthritis (RA) patients, STI-002 demonstrated an improvement in RA patients' pain symptoms, functions, quality of life and inflammation markers while also inhibiting bone and joint injuries. STI-002 (3mg/kg) plus MTX demonstrated significant improvement in ACR 20, 50 and 70 (77%, 50% and 20% respectively), similar clinical efficacy reported for Remicade and biosimilars of Remicade. Notably, the immunogenicity and anti-drug antibody formation (ADA) is drastically reduced for STI-002 compared to Remicade (<5% vs ~40%).