Aktis Oncology Inc. (NASDAQ: AKTS) released first-in-human clinical imaging and dosimetry data for AKY-2519, a radioconjugate targeting B7-H3 expressing tumors. The data will be presented at the 2026 American Society of Clinical Oncology Annual Meeting from May 29 to June 2 in Chicago.

Two separate assessments evaluated AKY-2519 in patients with metastatic castration-resistant prostate cancer and various solid tumor types. The studies demonstrated tumor uptake and normal tissue exposure levels, according to the company's statement.

The first assessment, conducted at the University of Pretoria and Steve Biko Academic Hospital in South Africa, evaluated 16 patients with metastatic castration-resistant prostate cancer. Patients received imaging agents and underwent PET/CT and SPECT/CT scans at various time points to measure distribution and dosimetry.

The second assessment, conducted at University Hospital Essen in Germany, evaluated 18 patients with advanced or metastatic solid tumors including prostate, lung, and colorectal cancers. Patients underwent PET/CT imaging at 15, 60, and 120 minutes after administration.

Both assessments reported no adverse events or infusion-related reactions. The studies measured standardized uptake values across different tumor types and normal tissues. Predicted absorbed doses were calculated for normal tissues including bone marrow, liver, kidneys, and salivary glands.

Aktis is currently enrolling patients in a Phase 1b trial of AKY-2519 for metastatic castration-resistant prostate cancer, with preliminary data expected in 2027. The company plans to initiate a second Phase 1b trial for other B7-H3 expressing solid tumors in the second half of 2026.

AKY-2519 is Aktis' second clinical-stage program using its miniprotein radioconjugate platform. The company's lead program, AKY-1189, targets Nectin-4 expressing tumors and is currently in Phase 1b trials with preliminary data expected in the first quarter of 2027.