Purpose: Folate receptor α (FRα) is expressed in most ovarian cancers. However, only patients with high expression levels are eligible for Elahere, an FRα-targeted microtubule inhibitor antibody–drug conjugate (ADC). Efficacy limitations and safety concerns underscore the need to develop next-generation FRα-targeted ADC to treat tumors expressing variable levels of FRα and incorporate different payloads to reduce safety risks. Herein, we present the characterization of AZD5335, a novel FRα-targeted topoisomerase-1 inhibitor ADC. Experimental Design: The efficacy of AZD5335 was assessed and correlated with FRα expression using cell- and patient-derived models. Focusing on models with low FRα, AZD5335 was directly compared with an Elahere analogue. Additionally, AZD5335 was evaluated in a model of acquired Elahere resistance. Combined treatments, including AZD5335 plus either standard-of-care drugs or a PARP1 inhibitor, were also explored. Results: A single dose of AZD5335 (2.5 mg/kg) achieved an overall response rate of 82% in patient-derived ovarian cancer xenografts (n = 17). Antitumor responses were observed in models expressing both high and low levels of FRα. Specifically within FRα-low models, AZD5335 demonstrated superiority over an Elahere analogue. In the context of acquired Elahere resistance, AZD5335 treatments resulted in complete tumor regressions. Additionally, combining AZD5335 with standard-of-care drugs or a PARP1 inhibitor resulted in enhanced efficacy and sustained durability. Two clinical case studies that demonstrated significant AZD5335 responses in tumors exhibiting high and low FRα expression are also provided. Conclusions: AZD5335 is a promising next-generation ADC capable of targeting ovarian cancers with both high and low FRα expression. AZD5335 demonstrates efficacy in overcoming Elahere resistance and supports combined treatment strategies.

Background/Objectives: The development of antibody–drug conjugates (ADCs) presents significant scientific and operational challenges, from optimising conjugation chemistry and linker stability to establishing robust analytical controls. Advanced analytical methods, particularly the combination of plasma stability assays with enzymatic studies, are essential for early screening and characterisation of ADC candidates. Integrating these in vitro assays with powerful data analysis software accelerates structure–activity relationship assessments and the identification of stable compounds in plasma. Methods: This article examines how combined analytical and computational approaches enhance candidate selection by offering valuable insights into the metabolic fate and stability risks of ADCs. Results: Our research shows correlation between in vitro stability profiles and in vivo pharmacokinetic (PK) data, demonstrating the predictive power of early-stage analytical studies. Implementation of software-driven visualisation and analysis enables faster, data-informed decision making, streamlining the triage process to prioritise candidates with optimal PK and pharmacodynamics (PD) characteristics. Conclusions: These findings highlight the critical need for integrated in vitro analytics and computational tools in efficient ADC development, supporting the selection of candidates with the greatest potential for clinical success and facilitating a more effective and accelerated path from discovery to clinical application.

Assessment of AZD5335/TOP1i-mediated DDR.

AZD5335 Pharmacokinetic Parameters

Purpose:Folate receptor α (FRα) is expressed in most ovarian cancers. However, only patients with high expression levels are eligible for Elahere, an FRα-targeted microtubule inhibitor antibody–drug conjugate (ADC). Efficacy limitations and safety concerns underscore the need to develop next-generation FRα-targeted ADC to treat tumors expressing variable levels of FRα and incorporate different payloads to reduce safety risks. Herein, we present the characterization of AZD5335, a novel FRα-targeted topoisomerase-1 inhibitor ADC.Experimental Design:The efficacy of AZD5335 was assessed and correlated with FRα expression using cell- and patient-derived models. Focusing on models with low FRα, AZD5335 was directly compared with an Elahere analogue. Additionally, AZD5335 was evaluated in a model of acquired Elahere resistance. Combined treatments, including AZD5335 plus either standard-of-care drugs or a PARP1 inhibitor, were also explored.Results:A single dose of AZD5335 (2.5 mg/kg) achieved an overall response rate of 82% in patient-derived ovarian cancer xenografts (n = 17). Antitumor responses were observed in models expressing both high and low levels of FRα. Specifically within FRα-low models, AZD5335 demonstrated superiority over an Elahere analogue. In the context of acquired Elahere resistance, AZD5335 treatments resulted in complete tumor regressions. Additionally, combining AZD5335 with standard-of-care drugs or a PARP1 inhibitor resulted in enhanced efficacy and sustained durability. Two clinical case studies that demonstrated significant AZD5335 responses in tumors exhibiting high and low FRα expression are also provided.Conclusions:AZD5335 is a promising next-generation ADC capable of targeting ovarian cancers with both high and low FRα expression. AZD5335 demonstrates efficacy in overcoming Elahere resistance and supports combined treatment strategies.

Characterization of FRa ADC AZD5335.