CSPC PHARMA (01093) announced that its subsidiary, Shanghai Jinmantang Biotechnology Co., Ltd., in collaboration with Jiangsu Hengrui Medicine Co., Ltd., has received breakthrough therapy designation from the National Medical Products Administration (NMPA) of China for JSKN 003, a targeted HER2 dual-binding antibody-drug conjugate. The designated indication is for the treatment of HER2-positive patients with advanced colorectal cancer who have previously failed treatment with oxaliplatin, fluorouracil, and irinotecan.

Colorectal cancer is one of the most common malignancies worldwide. According to the International Agency for Research on Cancer (IARC), in 2022 there were approximately 1.9262 million new cases and 903,900 deaths due to colorectal cancer globally, ranking third and second in incidence and mortality among all malignancies, respectively. In China, the incidence of colorectal cancer is particularly high, second only to lung cancer, with over 500,000 new cases reported each year and a rising trend.

The currently approved drugs in China for HER2-positive patients with advanced colorectal cancer who have failed prior treatments include regorafenib, fruquintinib, and trifluridine/tipiracil; however, these options have shown limited efficacy, with a median progression-free survival (mPFS) of only 2-3.7 months and a median overall survival (mOS) of about 7-10 months. Hence, there remains a significant unmet clinical need in this patient population.

Early clinical research results of JSKN 003 in this indication have demonstrated outstanding efficacy and good safety, presenting a significant clinical advantage over existing treatment options. At the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, a pooled analysis of two clinical studies on "JSKN 003 Monotherapy for Advanced HER2-Positive (IHC3+) Gastrointestinal Tumors" was presented. This analysis included a Phase I study (JSKN003-101) conducted in Australia and a Phase I/II study (JSKN003-102) in China. As of February 28, 2025, a total of 50 patients with HER2-positive advanced gastrointestinal tumors (including 23 colorectal cancer patients) were enrolled in the two studies, 38% of whom had previously received ≥3 lines of anti-tumor therapy.

Preliminary results indicated that JSKN 003 monotherapy for patients with HER2-positive advanced colorectal cancer provided significant efficacy and good safety: among 21 colorectal cancer patients who had at least one tumor efficacy assessment, the objective response rate (ORR) was 61.9%, the disease control rate (DCR) was 95.2%, with an mPFS of 13.77 months and a median duration of response (mDoR) of 12.06 months. Notably, the ORR for 20 patients with BRAF V600E wild-type colorectal cancer reached 65.0%. In terms of safety, among 43 patients who received the recommended Phase II dose (RP2D), only 6 patients (14.0%) experienced ≥3 grade treatment-related adverse events (TRAEs), with 3 patients (7.0%) experiencing serious treatment-related adverse events (TRSAEs), and 7 patients (16.3%) requiring dose adjustments due to TRAEs. No TRAEs led to treatment discontinuation or death.

This marks the second breakthrough therapy designation granted to JSKN 003, with the first received in March 2025 for the treatment of platinum-resistant recurrent epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer. Currently, JSKN 003 is undergoing several Phase II and III clinical studies in China for the treatment of solid tumors, including breast cancer, ovarian cancer, and gastric cancer. The recent breakthrough therapy designation for JSKN 003 will help accelerate the research and review process for this product, aiming to benefit more cancer patients sooner.