Yannis Morel
Analyst · H.C. Wainwright
Thank you, Stephanie. Turning to Slide 14. On this slide, I would like to highlight why we are particularly excited about our next-generation Nectin-4 ADC program called IPH4502. As mentioned earlier, IPH4502 is a differentiated ADC built to improve both safety and efficacy through a novel design. This molecule is based on a proprietary humanized antibody that binds on the Nectin-4 target to a distant and non-overlapping epitope versus enfortumab. It is combined with a stable, cleavable and hydrophilic linker, which supports high systemic exposure of the ADC while minimizing the release free exatecan in the circulation and therefore, reducing the risk of off-target toxicity. The payload exatecan is a potent topoisomerase 1 inhibitor with strong bystander activity, enabling it to target not only Nectin-4 expressing tumor cells but also neighboring cells with lower or heterogeneous expression. Importantly, IPH4502 has demonstrated activity in models resistant to enfortumab vedotin, supporting its potential to address tumors that are either refractory to or progress after current standard therapies. Overall, the design of IPH4502 is intended to overcome key limitations of third-generation Nectin-4 ADCs and to deliver a more favorable therapeutic profile. Slide 15. Here, we position IPH4502 within the current Nectin-4 ADC landscape and highlight its key differentiating feature. As you can see, the majority of Nectin-4 ADCs currently in clinical development, including approved and late-stage assets are based on MMAE payloads such as enfortumab vedotin or PADCEV. While these therapies have demonstrated clinical activity, they are also associated with certain limitations, particularly in terms of safety and resistance mechanism. In contrast, IPH4502 is based on TOPO1 payload, exatecan, which we believe offers a differentiated mechanism of action. Importantly, this allows us to potentially overcome some of the limitations observed with MMAE-based conjugates, including activity in tumors that are resistant to or have progressed following enfortumab vedotin. Indeed, MMAE-based ADCs are largely developed in bladder first-line setting in direct competition with the approved standard of care when the trial of IPH4502 includes patients relapsing after enfortumab vedotin. In addition, as mentioned earlier, the strong bystander effect associated with exatecan may enable activity in tumors with low or heterogeneous Nectin-4 expression, thereby broadening the potential addressable patient population. Taken together, we believe that IPH4502 combines a differentiated design with a compelling mechanism, positioning it as a potential best-in-class TOPO1-based Nectin-4 ADCs. Turning to Slide 16. Here, we present new preclinical data supporting the profile of IPH4502 as a potential best-in-class TOPO1 Nectin-4 ADC. Starting on the left-hand side of the slide, in a CDX model with high Nectin-4 expression, IPH4502 demonstrates strong antitumor activity as other TOPO1 ADC do. However, the key differentiation emerged in models with low Nectin-4 expression where IPH4502 maintains meaningful antitumor activity while other TOPO1 ADC in clinical development show a clear loss of efficacy. This is particularly important as it highlights the unique ability of IPH4502 to remain active in tumors with lower target expression. Overall, across multiple in vivo models, we consistently observed a differentiated antitumor profile for IPH4502, supporting its potential as best-in-class agents, particularly in low to moderate Nectin-4 expressing tumors. We believe this profile is driven by the combination of a high affinity antibody with a unique epitope, a stable and hydrophilic linker and a strong bystander effect of exatecan. Now handing over to Sonia, who will present you the IPH4502 phase I trial.