Iksuda to present preliminary analysis of oesophageal cancer data from Phase 1 study of IKS014 at ASCO Gastrointestinal Cancer Symposium

Encouraging anti-tumour activity seen across all dose levels and in various tumour indications

Clinical benefit rate of 80% for 10 patients with HER2+ oesophageal cancer who had received prior therapy that included a trastuzumab component in at least one prior treatment

Newcastle, UK, 6 January 2026: Iksuda Therapeutics (Iksuda), the developer of class leading, antibody drug conjugates (ADCs), today announces the presentation of early analyses of activity in patients with oesophageal cancer during its Phase 1 study of IKS014, a human epidermal growth factor receptor 2 (HER2)-directed ADC, in patients with advanced HER2+ solid tumours, at the 2026 ASCO Gastrointestinal Cancers Symposium in San Francisco, US (8-10 January).

The Phase 1 study (NCT05872295) is a non-randomised, open-label, multicentre trial evaluating IKS014 in patients with locally advanced or metastatic solid tumours that express HER2. Data was presented from an unplanned sub-population of patients with oesophageal cancers from the dose escalation portion of the trial conducted in Australia, which was designed to establish the maximum-tolerated dose and/or recommended phase 2 dose for IKS014 as monotherapy and to provide initial safety, tolerability, efficacy, PK, PD, and immunogenicity data.

As of July 2025, 62 patients have been treated with IKS014 across five dose levels (40, 60, 90, 120 and 105 mg/m²), including 10 patients with HER2+ oesophageal cancers. Encouraging anti-tumour activity was seen across all dose levels in patients with a variety of tumour indications such as breast, ovarian, gallbladder, lung and oesophageal cancers, and in patients with HER2+ and HER2 low tumours.

Of the sub-set of 10 patients with HER2+ oesophageal cancer, who had received prior therapy (median 3, range 1-6), five achieved a response, including a complete response in one patient with non-measurable disease, whilst three other patients demonstrated stable disease for more than six months, resulting in a clinical benefit rate for IKS014 of 80%. These positive results warrant further exploration, and the dose expansion part of this Phase 1 study will now include an additional expansion cohort specifically for patients with HER2-expressing oesophageal adenocarcinoma who have previously received at least one prior line of standard treatment that may have included a HER2-directed therapy.

Dr. Dave Simpson, Chief Executive Officer, Iksuda Therapeutics, commented: “The early signs of activity and clinical benefit rate in patients with pretreated advanced oesophageal cancer is extremely encouraging. This is a notoriously difficult cancer to treat, with relatively poor survival rates and high treatment toxicity. We look forward to continuing to explore the potential of IKS014 to improve clinical outcomes in this hard-to-treat cancer, as well as across several other HER2-expressing cancers.”