Iksuda Wins FDA IND Clearance for CA242-Directed ADC IKS04 in GI Cancers

Iksuda Therapeutics announced that the FDA has cleared its Investigational

New Drug (IND) application for IKS04, a CA242-directed antibody-drug conjugate (ADC), enabling assessment in a phase 1 trial in patients with gastrointestinal (GI) cancers.¹ The clearance also covers what the company calls the "IKS04 Regimen," an innovative dosing approach designed specifically to address the challenge of solid tumor penetration for high-potency ADC payloads.¹

Dave Simpson, chief executive officer of Iksuda Therapeutics, said, "This IND clearance for IKS04 and the IKS04 Regimen, is another important step for Iksuda and further validation of our approach to designing and developing innovative ADCs with the optimal clinical calibration for a given target and indication."¹

How does IKS04 work?

IKS04 targets CA242, a carbohydrate antigen expressed on gastrointestinal tumors, and follows the same general design philosophy Iksuda applies across its ADC pipeline: selecting the combination of antibody, conjugation chemistry, linker, and payload mechanism intended to deliver the optimal therapeutic index for a given target and indication.¹ Like Iksuda's other ADC programs, IKS04 incorporates pro-drug technology built around glucuronide triggers, a linker chemistry designed to keep the ADC stable in systemic circulation and release its cytotoxic payload only once it reaches the tumor site.¹

Sara Jenkins, ADC commercial manager at Sterling Pharmaceutical Services, discussing glucuronide-triggered linker systems in an article with BioPharm International, said, "These linkers have a number of advantages, including the fact that lysosomal enzyme β-glucuronidase is abundant in lysosomes and over-expressed in some tumors, resulting in stable ADCs; and β-glucuronide is highly hydrophilic, leading to reduced ADC aggregation."²

This tumor-selective activation approach reflects a broader shift in ADC development priorities. Sabeen Mekan, MD, senior vice president and chief medical officer at Zymeworks, said in a BioPharm International video interview, "I think the biggest innovation moving forward is on the payload side," pointing to payload design and antibody engineering, alongside linker and conjugation advances, as the areas most likely to shape the next generation of ADCs.³

Iksuda's tumor-selective activation approach has already been clinically validated in the company's more advanced pipeline programs, including IKS014, a HER2-directed ADC currently in a phase 1 dose-expansion trial for HER2-positive and HER2-low solid tumors, and IKS03.¹ The company said this design concept drives improved tolerability compared with traditional ADC linker chemistries.¹

Why does the dosing regimen matter as much as the molecule itself?

Iksuda describes the IKS04 Regimen as an innovative dosing approach specifically designed to overcome the challenge of solid tumor penetration for high-potency payloads, a distinct innovation the company is advancing alongside IKS04's underlying linker and target biology.¹

What happens next?

With IND clearance secured, Iksuda will move IKS04 into a phase 1 trial evaluating the ADC and its accompanying dosing regimen in patients with gastrointestinal cancers. The company's broader ADC pipeline, including the more advanced IKS014 and IKS03 programs, continues to serve as the clinical proof-of-concept for the tumor-selective, glucuronide-triggered activation approach IKS04 also relies on.¹

References

1. Iksuda Therapeutics. Iksuda Receives US FDA IND Clearance for IKS04. Press Release, BusinessWire, July 29, 2026. https://www.businesswire.com/news/home/20260729428965/en/Iksuda-receives-US-FDA-IND-clearance-for-IKS04
2. Challener CA. Exploring the Optimization of Linker Chemistries for ADCs. BioPharm International. December 13, 2023. https://www.biopharminternational.com/view/exploring-the-optimization-of-linker-chemistries-for-adcs
3. Novel Payloads and Multispecific Antibodies Fuel ADC Innovation. BioPharm International. June 2026. https://www.biopharminternational.com/view/novel-payloads-and-multispecific-antibodies-fuel-adc-innovation