Ataxia Telangiectasia and Rad3-Related (Atr) Inhibitor Camonsertib Dose Optimization in Patients With Biomarker-Selected Advanced Solid Tumors (Tresr Study)

Authors

Elisa Fontana
Ezra Rosen
Elizabeth K Lee
Martin Højgaard
Niharika B Mettu
Stephanie Lheureux
Benedito A Carneiro
Gregory M Cote
Louise Carter
Ruth Plummer
Devalingam Mahalingam
Adrian J Fretland
Joseph D Schonhoft
Ian M Silverman
Marisa Wainszelbaum
Yi Xu
Danielle Ulanet
Maria Koehler
Timothy A Yap

Publication Date

9-1-2024

Journal

Journal of the National Cancer Institute

Abstract

BACKGROUND: Camonsertib is a selective oral inhibitor of ataxia telangiectasia and Rad3-related (ATR) kinase with demonstrated efficacy in tumors with DNA damage response gene deficiencies. On-target anemia is the main drug-related toxicity typically manifesting after the period of dose-limiting toxicity evaluation. Thus, dose and schedule optimization requires extended follow-up to assess prolonged treatment effects.

METHODS: Long-term safety, tolerability, and antitumor efficacy of 3 camonsertib monotherapy dosing regimens were assessed in the TRESR study dose-optimization phase: 160 mg once daily (QD) 3 days on, 4 days off (160 3/4; the preliminary recommended Phase II dose [RP2D]) and two step-down groups of 120 mg QD 3/4 (120 3/4) and 160 mg QD 3/4, 2 weeks on, 1 week off (160 3/4, 2/1w). Safety endpoints included incidence of treatment-related adverse events (TRAEs), dose modifications, and transfusions. Efficacy endpoints included overall response rate, clinical benefit rate, progression-free survival, and circulating tumor DNA (ctDNA)-based molecular response rate.

RESULTS: The analysis included 119 patients: 160 3/4 (n = 67), 120 3/4 (n = 25), and 160 3/4, 2/1w (n = 27) treated up to 117.1 weeks as of the data cutoff. The risk of developing grade 3 anemia was significantly lower in the 160 3/4, 2/1w group compared with the preliminary RP2D group (hazard ratio = 0.23, 2-sided P = .02), translating to reduced transfusion and dose reduction requirements. The intermittent weekly schedule did not compromise antitumor activity.

CONCLUSION: The 160 3/4, 2/1w dose was established as an optimized regimen for future camonsertib monotherapy studies offering a substantial reduction in the incidence of anemia without any compromise to efficacy.

CLINICAL TRIAL ID: NCT04497116.

Keywords

Humans, Female, Male, Middle Aged, Neoplasms, Ataxia Telangiectasia Mutated Proteins, Aged, Adult, Biomarkers, Tumor, Protein Kinase Inhibitors, Dose-Response Relationship, Drug, Aged, 80 and over

Comments

Associated Data

PMID: 38710487