Claudin 6–Targeted ADC Shows Activity in Germ Cell Tumors

In an interview with Targeted Oncology at the 2026 ESMO Congress, Darren Feldman, MD, genitourinary medical oncologist and section head, Germ Cell Cancer at Memorial Sloan Kettering Cancer Center, discusses findings on ixotatug vedotin (TORL-1-23), an investigational claudin 6 (CLDN6)–targeted antibody-drug conjugate (ADC), in patients with heavily pretreated germ cell tumors (GCTs).

In the phase 1 dose-escalation CATALINA-1 study (NCT05103683), 5 of 11 patients (45.5%) achieved an objective response, and the disease control rate was 73%.¹ Median progression-free survival was nearly 6 months. Responses were observed in 3 of 6 patients who had previously received high-dose chemotherapy and stem cell transplantation. One patient had an ongoing response nearly 4 years after initiating treatment at the time of data cutoff.

He also discusses the safety profile of ixotatug vedotin, which was generally consistent with that of ADCs carrying a monomethyl auristatin E (MMAE) payload. Most adverse events were low grade, although reversible grade 4 neutropenia and grade 3 peripheral neuropathy were reported. One patient discontinued treatment because of peripheral neuropathy, and no treatment-related deaths occurred.

Feldman outlines next steps for the investigational agent, including continued enrollment in the phase 1 study to expand the GCT cohort and discussions around a potential phase 2 trial that could support registration. Further investigation will help clarify the role of CLDN6-targeted therapy in this heavily pretreated population.

REFERENCES

1. Oliai C, Feldman DR, Slotkin E, et al. Clinical safety and efficacy of ixotatug vedotin (TORL-1-23), a claudin 6-targeted ADC, as monotherapy in germ cell tumors (GCT). Presented at: 2026 ESMO Congress; October 23-27, 2026; Madrid, Spain. Abstract 1210RO.