I-Mab, a clinical-stage biopharmaceutical company, announced that the Center for Drug Evaluation (CDE) of China National Medical Products Administration (NMPA) has accepted the company's IND application to initiate a phase 2 trial for enoblituzumab (also known as TJ271) in combination with pembrolizumab (Keytruda) in patients with selected solid tumors in China. I-Mab has in-licensed the rights to exclusively develop and commercialize enoblituzumab in Greater China from MacroGenics (Nasdaq: MGNX).

Enoblituzumab is a highly differentiated humanized monoclonal antibody directed against B7-H3, a member of the B7 family of T-cell checkpoint regulators. B7-H3 plays a key role in regulating immune response against cancers and is widely expressed in multiple cancers. Its presence on tumors is associated with poor clinical prognosis. Enoblituzumab is engineered with an optimized Fc domain that enables a dual anti-tumor mechanism by antibody-dependent cell-mediated killing of cancer cells and enhanced T-cell immune response. There are increasing preclinical data generated by I-Mab and preliminary clinical evidence from MacroGenics supporting increased efficacy for the combination of enoblituzumab and PD-1 antibody against cancers.

Enoblituzumab has become one of the Company's core clinical assets. The phase 2 clinical trial in China will evaluate the efficacy of the combination of enoblituzumab and pembrolizumab. It is designed as a basket clinical trial involving non-small cell lung cancer (NSCLC), urothelial carcinoma, and other selected cancer types based on treatment signals observed in previous studies conducted by MacroGenics.

MacroGenics conducted multiple clinical studies of enoblituzumab for the treatment of cancers including squamous cell carcinoma of head and neck (SCCHN) and NSCLC; demonstrating enoblituzumab is well tolerated with observed efficacy signals. For example, data from a phase 1 cohort expansion study, presented at SITC 2018, have reported that enoblizutumab in combination with PD-1 antibody achieved an objective response rate (ORR) of 33.3% in SCCHN patients and of 35.7% in NSCLC patients with PD-L1 expression <1%. Currently, MacroGenics is conducting a phase 2 study of enoblituzumab in combination with retifanlimab (PD-1 antibody) or tebotelimab (PD-1 & LAG-3 bispecific DART molecule) for first-line treatment of patients with recurrent or metastatic SCCHN.

“With the initiation of the phase 2 clinical trial we hope to accelerate the clinical development of enoblituzumab in Greater China,” said Dr. Joan Shen, CEO of I-Mab. “We will be leveraging the data from clinical trials conducted by MacroGenics to advance the clinical development of enoblituzumab for approval in Greater China.”

Enoblituzumab is an investigational Fc-optimized monoclonal antibody that targets B7-H3, a member of the B7 family of immune regulator proteins. B7-H3 is widely expressed by many different tumor types and may play a key role in regulating the immune response to various types of cancer. Enoblituzumab has been or is currently being evaluated in clinical trials as a monotherapy or in combination with anti-PD-1-based therapies in patients with B7-H3-expressing cancers. I-Mab Biopharma acquired the development and commercial rights from MacroGenics for Greater China.