ceralasertib (AZD6738)

P1/2, N=357, Active, not recruiting, AstraZeneca | Trial completion date: Dec 2025 --> Jun 2026

P2, N=174, Active, not recruiting, Institute of Cancer Research, United Kingdom | Recruiting --> Active, not recruiting | Trial completion date: Apr 2026 --> Aug 2026 | Trial primary completion date: Apr 2026 --> Aug 2026

Mechanistically, 38a arrested cell cycle progression, induced apoptosis, inhibited colony formation and migration, and suppressed DNA damage repair pathways, outperforming combined Niraparib and AZD6738. These findings underscore the therapeutic potential of PARP1/ATR dual inhibitors for breast cancer and support further investigation.

Ceralasertib monotherapy demonstrated promising anti-tumor activity in ARID1A-deficient gynecologic malignancies. Tumor molecular and immune correlates may inform the further development of ATR inhibitors in this patient population.

Preclinical studies demonstrate that ATR inhibition disrupts replication stress tolerance, impairs homologous recombination, and disables checkpoint control, enhancing cytotoxicity from standard therapies including gemcitabine, FOLFIRINOX, fluoropyrimidines, and radiotherapy...Early-phase clinical trials of ATR inhibitors (ART0380, AZD6738, BBI-355) alone or in combination show promising safety, tolerability, and preliminary efficacy. In this review, we summarize current literature on targeting the ATM-CHK2 and ATR-CHK1 pathways in PC, highlighting preclinical evidence, clinical developments, and strategies for biomarker-driven, precision oncology approaches.

CD8+ T cell depletion completely abrogates the anti-tumor effects, suggesting their essential role in mediating therapeutic responses. These findings establish Gal-9 upregulation as a critical adaptive immune resistance mechanism constraining ATRi efficacy, providing a compelling rationale for clinical translation of ceralasertib/Gal-9 blockade combinations.

We provide a detailed analysis of the structure-activity relationships (SAR) of leading clinical candidates, including berzosertib, ceralasertib, and elimusertib, focusing on strategic chemical modifications such as scaffold hopping and sulfoximine substitution to optimize selectivity and druggability. Critical challenges, specifically dose-limiting hematological toxicities and acquired resistance, are analyzed alongside the search for robust predictive biomarkers. By synthesizing current pharmacological and clinical data, this work outlines the trajectory for next-generation ATR-targeted precision medicine.

We exploited this vulnerability by inhibiting the ATR-mediated DNA damage response pathway with the selective ATR inhibitor ceralasertib (AZD6738)...Given the frequent inactivation of p53 in lung cancer, our study offers a rationale for clinical exploration of ATR inhibitors, in combination with standard chemotherapy, in the context of reduced BOK function. Future investigations into the broader role of BOK in genomic stability and nucleotide metabolism may uncover additional therapeutic strategies for cancers with repressed BOK.

Over the last decade, intensive medicinal chemistry efforts have generated a broad pipeline of ATR inhibitors, including ceralasertib, elimusertib, camonsertib, berzosertib, ART0380, and gartisertib, many of which are in Phase I/II clinical trials. Incorporating these strategies into adaptive platform trials with pharmacodynamic markers and patient-centered outcomes will speed up translation. Overall, ATR inhibitors highlight progress in DNA damage response therapies, from understanding mechanisms to biomarker-driven clinical use, with the potential to revolutionize treatment across various cancers.

Our findings identify a dose-dependent, hypomorphic HRR restoration by ∆exon11 BRCA1, help explain the variable resistance observed in BRCA1-mutant pre-clinical models expressing this hypomorph, and propose ATR inhibition in combination with PARPi as a clinical strategy to counteract therapeutic resistance mediated by ∆exon11 BRCA1 hypomorphs.

P3, N=630, Suspended, National Cancer Institute (NCI) | Recruiting --> Suspended

P1, N=1, Terminated, AstraZeneca | N=20 --> 1 | Recruiting --> Terminated; The study terminated because the clinical development programme for Ceralasertib has been discontinued.