DS1025 has entered clinical development in patients with advanced solid tumors as novel CD25 directed Antibody Drug Conjugate (ADC) in industry-leading ADC portfolio of Daiichi Sankyo.

The first patient has been dosed in a first-in-human phase 1 trial evaluating DS1025 in adult patients with advanced or metastatic solid tumors with disease progression on or after at least one prior line of standard therapy.

DS1025 is a specifically engineered, investigational, potential first-in-class CD25 directed ADC containing an immuno-oncology optimised cytotoxic payload discovered by Daiichi Sankyo.

CD25 is a cell surface protein that is highly expressed on regulatory T cells (Treg cells) which suppresses the response of the immune system against cancer, making it a promising therapeutic target.

Currently, there are no CD25-directed ADCs approved for any type of cancer.

John Tsai, Managing Director (MD), Global Head, Research and Development (R&D), Daiichi Sankyo, said, “While immunotherapies have transformed cancer treatment, continued innovation in leveraging pathways that can activate the immune system is needed. The initiation of this trial evaluating DS1025 reflects continued progress in advancing our pipeline through the development of novel Antibody Drug Conjugates in order to deliver medicines that improve outcomes for patients with cancer.”

The multicenter, open-label, first-in-human, dose escalation phase 1 trial will assess the safety, tolerability, pharmacokinetics and preliminary efficacy of DS1025 in patients with advanced or metastatic solid tumors with disease progression on or after at least one prior line of standard therapy.

The trial will evaluate primary endpoints of safety and tolerability, including dose-limiting toxicities and adverse events. Secondary endpoints include pharmacokinetics and immunogenicity. Exploratory endpoints include Overall Response Rate (ORR), Duration of Response (DoR) and time to response.

The trial is expected to enroll up to 45 patients across multiple sites in Asia and Europe.