China NMPA Accepts IND Application for Eftansomatropin Pivotal Trial in Pediatric Patients with Growth Hormone Deficiency

August 4,2020

I-Mab (the "Company") (Nasdaq: IMAB), a clinical stage biopharmaceutical company committed to the discovery, development and commercialization of novel biologics, today announced that the China National Medical Products Administration (NMPA) has accepted its pivotal trial application for eftansomatropin (also known as TJ101) as a weekly treatment for growth hormone deficiency in pediatric patients (PGHD).

Eftansomatropin is an innovative long-acting recombinant human growth hormone (rhGH) with a novel molecular format utilizing Genexine's patented half-life extension hyFc® fusion technology, which stimulates the production of insulin-like growth factor 1 (IGF-1) in the liver, alongside growth-stimulating effects on a variety of tissues, including osteoblast and chondrocyte activities that stimulate bone growth. Additionally, preliminary research and trials have proved that as a natural protein based rhGH, eftansomatropin has not shown safety concerns typically associated with conventional pegylated rhGH drugs on the market, while maintaining comparable efficacy.

The Phase 3 trial is a multi-center, randomized, open-label, active-controlled clinical study designed to assess the safety, efficacy and pharmacokinetics of eftansomatropin in PGHD. The primary objective is to demonstrate non-inferiority of eftansomatropin administered in subcutaneous injection, compared to the active control Norditropin® (somatropin), a daily rhGH marketed in China. About 165 subjects will be enrolled and treated in the study.

"The China NMPA's acceptance of this pivotal IND for eftansomatropin represents an important step towards bringing this innovative product to the Chinese market as planned," said Dr. Joan Shen, CEO of I-Mab. "With eftansomatropin, we will be able to potentially address a substantial unmet medical need with a safer, highly differentiated, and convenient therapy for pediatric patients suffering from the growth hormone deficiency."

The Company owns the rights of eftansomatropin from Genexine Inc. (KOSDAQ: 095700) for development, manufacturing and commercialization in China. Genexine has previously completed three clinical trials with eftansomatropin in Europe and Asia, including one Phase 1 trial in healthy adult volunteers, one Phase 1b/2 multi-regional trial in adults with growth hormone deficiency (NCT02946606), and one Phase 2 multi-regional trial in PGHD (NCT03309891). Overall, eftansomatropin was shown to be well-tolerated, and has met clinical efficacy endpoints by weekly or twice-monthly administration.

According to Frost & Sullivan, PGHD affected approximately 3.4 million patients in Greater China, but only 3.7% of all PGHD patients were receiving growth hormone replacement therapy, which primarily consists of daily injections of rhGH. Recombinant human growth hormone therapy has been included in the National Reimbursement Drug List in China.