Cantargia

• Anti-IL1RAP ADC demonstrated potent anti-tumor efficacy and was well tolerated in pre-clinical models
• Anti-IL1RAP ADC targets IL1RAP, which is overexpressed in many tumors and their tumor microenvironment

Cantargia (Cantargia AB; Nasdaq Stockholm: CANTA) today released a poster with new preclinical data that strengthens the rationale behind the development of novel anti-IL1RAP ADCs. The current study shows the potential of interleukin-1 receptor accessory protein (IL1RAP) as a target for ADC therapy across a broad spectrum of cancers. The poster is presented at the American Association for Cancer Research (AACR) Annual Meeting.

“IL1RAP is an attractive target from an ADC perspective and the data presented show that conjugation of a toxic payload to an anti-IL1RAP antibody has strong potential as a safe and effective anti-tumor therapeutic. In addition, these data illustrate the strength of Cantargia’s CANxx platform which contains numerous antibodies with different properties that can be developed into new IL1RAP-based therapies”, said David Liberg, Chief Scientific Officer of Cantargia.

An anti-IL1RAP ADC was generated from an antibody selected from Cantargia’s unique library of IL1RAP-targeting antibodies and conjugated to a tubulin-targeting payload using ImmunoGen (now part of AbbVie) proprietary technology. More background information can be found in the press release issued on March 25, 2025 on the AACR abstract release.

Preclinical data on the novel anti-IL1RAP ADC shows effective tumor growth inhibition with potent dose-dependent anti-tumor activity in a high IL1RAP expressing tumor model. Notably, a single dose of the ADC led to long-lasting efficacy, demonstrating 100% survival by day 95 in the high target expression model, compared to 60% in animals treated with a control ADC (non-targeting antibody conjugated to the same linker-payload). Strong tumor growth inhibition could also be achieved in a low IL1RAP expressing tumor model. This demonstrates the effectiveness of anti-IL1RAP ADC treatment across different target expression levels. Additionally, no marked changes in body weight, liver and kidney enzyme levels are noted, and absence of histological changes in the internal organs assessed underscores safety and tolerability of the tested anti-IL1RAP ADCs.

All the studies involving anti-IL1RAP ADCs were performed in collaboration with ImmunoGen (now part of AbbVie). Details of the poster are given below:

Poster number: 2875
Poster title: IL1RAP-targeting antibody-drug conjugate: A novel therapeutic targeting both tumor cells and the tumor microenvironment.
Session date: April 28, 2025

The poster will be presented at the AACR annual meeting 2025 in Chicago, IL on April 28 from local time 2-5pm by Dr. Elin Jaensson Gyllenbäck from Cantargia. The poster will be uploaded on Cantargia’s webpage www.cantargia.com.