Ligachem Bioscience: "80% Clinical Benefit for HER2 ADC in Phase 1 Esophageal Cancer Trial"

Ligachem Bioscience announced on January 7 that its partner company, Iksuda Therapeutics, will present preliminary results from the Phase 1 clinical trial of 'IKS014 (LCB14)', a HER2 (human epidermal growth factor receptor 2)-targeted ADC candidate, at the '2026 ASCO Gastrointestinal Cancers Symposium' to be held in San Francisco, USA, from January 8 to 10.

This presentation will include a subgroup analysis of esophageal cancer patients from the Phase 1 clinical trial (NCT05872295), which evaluated the efficacy and safety of IKS014 in patients with advanced HER2-positive solid tumors. The clinical trial results being presented are from the dose escalation stage conducted in Australia, and the study was designed to determine the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D) of IKS014 monotherapy, as well as to assess its safety, tolerability, efficacy, and pharmacokinetics (PK).

As of July last year, a total of 62 patients received IKS014 at five different dose levels (40, 60, 90, 120, and 105 mg/m²), including 10 patients with HER2-positive esophageal cancer.

According to the analysis, clinical benefit was observed in 8 out of 10 esophageal cancer patients who had previously received standard treatment, including the HER2-targeted antibody trastuzumab. Specifically, 5 patients showed a response, including 1 complete response (CR), and 3 patients maintained stable disease (SD) for more than 6 months, resulting in an objective response rate (ORR) of 50% and a clinical benefit rate (CBR) of 80%.

IKS014 demonstrated consistent antitumor activity not only in esophageal cancer but also across various solid tumor types, including breast, ovarian, gallbladder, and lung cancers. Notably, positive responses were observed not only in HER2-positive patients but also in those with low HER2 expression (HER2-low), demonstrating broad potential for expansion.

Based on these encouraging results, Iksuda Therapeutics announced plans to add a 'HER2-expressing esophageal cancer' cohort in the dose expansion phase of the ongoing Phase 1 trial. This is expected to further demonstrate the market expansion potential of IKS014.

Meanwhile, at the '2025 ESMO' conference held in October last year, Iksuda Therapeutics released the first results from the Phase 1 trial of IKS014. At that time, among 11 breast cancer patients treated with doses of 90 mg/m² or higher, the ORR was 64%, and among HER2-positive breast cancer patients, the ORR reached 100%. Notably, even among patients who had previously received the HER2 ADC 'Enhertu (Trastuzumab Deruxtecan)', an ORR of 75% was observed, demonstrating the value of IKS014 as a treatment option for patients with resistance or non-responsiveness to Enhertu-an emerging topic in the ADC industry.

The meaningful efficacy and safety of IKS014 to be released at this ASCO GI symposium are expected to reaffirm the competitiveness of Ligachem Bioscience's ADC platform.