Molecular Partners updates on DLL3 and MSLN Radio-DARPin programs

Molecular Partners AG said on July 6, 2026 that dosing of patients is ongoing in the first cohort of the US multicenter Phase 1/2a study of MP0712, which targets DLL3 and carries the payload Lead-212, developed with Orano Med for small cell lung cancer and other neuroendocrine cancers¹. The Phase 1 study contains up to 4 dose levels, with each patient receiving up to 4 doses within their assigned dose level, and five centers are currently open and recruiting¹. Initial data from the study are expected within the next months, with a more comprehensive dataset on safety and efficacy expected in 2027¹.

Separately, the company disclosed a new compassionate-care initiative in South Africa. Dr. Mike Sathekge of the Nuclear Medicine Research Institute in South Africa requested an early-access clinical program, under Section 21 of the country's Medicines and Related Substances Act, using a DLL3-targeting Radio-DARPin referred to as MP0714. In this program, 177Lu is used to image patients while 225Ac is used to treat them, functioning as a theranostic pair¹. Molecular Partners said it remains fully focused on executing the US Phase 1/2a study of MP0712 with 212Pb¹, distinguishing that trial from the South African compassionate-care effort. PanTera, a radioisotope producer, is among the suppliers of 225Ac for MP0714's use at the Nuclear Medicine Research Institute¹.

On the company's second radiopharmaceutical candidate, MP0726 targets mesothelin, a tumor target overexpressed in several cancers including ovarian cancer, and the company plans to advance it toward first-in-human imaging in the second half of 2026¹. The company also plans two INDs across its pipeline in 2027 and expects to nominate a new radiotherapeutic target in the second half of this year¹.