Sairopα’s anti-CTLA4 Antibody Shows Clinical Efficacy with a Mild Safety Profile

ROTTERDAM, Netherlands – June 1st, 2024 –

Sairopα, a clinical-stage developer of innovative cancer therapies, presented updated results from its dose-escalation phase of the ongoing Phase 1 study evaluating safety, pharmacokinetics and clinical efficacy of ADU-1604 (anti-CTLA4 antibody) in advanced PD-1 relapsed/refractory melanoma patients at the American Society of Clinical Oncology (ASCO) Annual Meeting 2024 in Chicago.

Data from the completed dose-escalation study (n=20) in PD-1 relapsed/refractory melanoma patients shows that ADU-1604 is well tolerated at dosages of 25, 75, 225 and 450 mg Q3W, demonstrating a mild safety profile and no dose-limiting toxicities. Early signs of clinical efficacy were observed in three patients (two patients at 225 mg and one patient at 450 mg). Dose-dependent increase of pharmacodynamic biomarkers was detected, including strong increase of CD8+ T-cell proliferation in patients that showed tumor reduction.

The currently ongoing dose-expansion phase will treat an additional 20 patients (n=20) at the recommended Phase 2 dose (RP2D) of 225mg to support potential future combination therapies.

For more detailed information, please download our poster presentation below:

About Sairopα: 
Based in Rotterdam, The Netherlands, Sairopα aims to revolutionize cancer treatment through groundbreaking immunotherapy research. Backed by Van Herk Investments, Sairopα’s innovative therapeutic pipeline aims to transform cancer treatment and improve outcomes for patients globally. Sairopα is developing proprietary ADU-1604 (anti-CTLA4) and ADU-1805 (anti-SIRPalpha) antibodies in Phase 1 clinical development as well as a yet undisclosed bispecific antibody in preclinical development.

For more information about Sairopa, please visit

Contact Information:
For more information, please visit Sairopα’s website or contact:
Sairopα B.V. CIC Stationsplein 45 Unit A4.004 3013 AK Rotterdam The Netherlands