Undisclosed immunostimulatory ADC / Astellas, Sutro Biopharma - LARVOL DELTA

ASP2998, a trophoblast cell-surface antigen 2 (TROP2)–targeted immunostimulatory antibody-drug conjugate with dual payloads, in patients with locally advanced unresectable or metastatic solid tumors: A phase 1b/2 study. (ASCO 2026) - P1/2 | "ASP2998 is a dual-payload (topoisomerase I inhibitor plus stimulator of interferon genes [STING] agonist) immunostimulatory ADC targeting TROP2...Eligible DEXP pts with urothelial carcinoma include those who have received ≤3 prior lines of therapy and progressed on or after enfortumab vedotin plus pembrolizumab...Recruitment is ongoing with 196 planned pts (36 in DESC; 160 in DEXP). ClinicalTrials.Gov Identifier: NCT07287995."

ADC • Clinical • First-in-human • Metastases • P1/2 data • Breast Cancer • Gastric Cancer • HER2 Negative Breast Cancer • Lung Cancer • Non Small Cell Lung Cancer • Oncology • Solid Tumor • Urothelial Cancer • HER-2 • PD-L1 • STING • TACSTD2

Sutro will have a poster presentation at the…Society for Immunotherapy of Cancer (SITC) 2025 Annual Meeting…highlighting preclinical results that demonstrate the ability of novel immunostimulatory dual-payload ADCs to enhance therapeutic index and overcome patient resistance (GlobeNewswire)

Preclinical • Solid Tumor

Next-Generation ADC Collaborations (GlobeNewswire) - "Two research and development programs are progressing under Sutro’s collaboration with Astellas focused on dual-payload immunostimulatory ADCs (iADCs), including one program that entered an IND-enabling toxicology study in the first quarter of 2025."

Preclinical • Oncology

Next-Generation Immunostimulatory Antibody-Drug Conjugates (iADCs) Combine Tumor Cell Killing with Immune Activation to Induce Durable Antitumor Immunity (SITC 2025) - "However, their efficacy can be limited in tumors with low antigen expression, tumor cell heterogeneity, or acquired resistance.Methods To address these challenges, we are developing dual-payload ADCs, including immunostimulatory ADCs (iADCs), which simultaneously deliver both a cytotoxin and an immune stimulator directly to the tumor cells...Notably, complete responders exhibited durable immune memory, effectively rejecting MC38-HER2 tumors in rechallenge experiments. Furthermore, iADCs were well tolerated in non-human primates at 25 mg/kg administered every three weeks for two doses (Q3W ×2), indicative of a favorable safety profile and supporting advancement towards clinical development.Conclusions These findings highlight the potential of iADCs as a novel treatment option that integrates targeted cytotoxicity with immune engagement, offering a promising approach to address resistance and improve long-term outcomes in cancer treatment."

Tumor cell • Oncology