Abstract PO5-10-08: Clinical Value of Molecular Targets and Genome-Targeted Cancer Therapies Recommended by the National Comprehensive Cancer Network for Advanced Breast Cancer
Authors: Tibau Ariadna , Hwang Thomas J. , Avorn Jerry , Kesselheim Aaron 
Published: May 2024

Background: Genomic testing has expanded the possibilities of precision cancer medicine, particularly for advanced, treatment-resistant breast cancer cases. However, the clinical significance of most genetic alterations remains uncertain, potentially overestimating tailored therapies. The National Comprehensive Cancer Network (NCCN) guidelines are evidence-based cancer-specific recommendations used in clinical practice and that are often determinative for insurance coverage. In this study, we assessed the validity of the targets and the clinical benefit of genome-targeted cancer drugs recommended in the NCCN guidelines for metastatic breast cancer.

Methods: We identified genome-targeted oncology therapies supporting advanced breast cancer recommendations in the most recent NCCN breast cancer guideline (version 4.2023). Genome-targeted drugs were defined as involving use of a genomic test in which the drug targeted a genomic alteration. We analyzed data from trials supporting advanced genome-targeted breast cancer drugs recommendations. When multiple (or overlapping) articles for the same study were identified, the most recent publication was included. We extracted key details of each trial, including trial design, blinding, phase of clinical trial and primary efficacy end points. We cross-referenced the FDA-approved indications as of 30 June 2023 with the NCCN recommendations for each drug. Strength of evidence supporting molecular targetability was evaluated using the European Society for Medical Oncology (ESMO) Scale for Clinical Actionability of molecular Targets (ESCAT). Clinical benefit for genome-targeted oncology therapies was assessed using the ESMO-Magnitude of Clinical Benefit Scale (ESMO-MCBS). We considered a substantial clinical benefit as a grade of 4 or 5. Molecular targets qualifying for ESCAT category level I-A and I-B associated with substantial clinical benefit by ESMO-MCBS were rated as high-benefit genomic-targeted breast cancer treatments.

Results: We identified 47 recommendations supporting 17 genome-targeted drugs, which targeted 11 driver alterations. Out of these recommendations, 29 (62%) aligned with the FDA indications. We associated 47 trials with these recommendations, most randomized (24, 51%), phase 3 (23, 49%) and open-label (42, 89%). The most common primary endpoint (22, 47%) was overall response rate, followed by progression-free survival/time to progression (21, 45%). Twenty-four trials (51%) had a I-A ESCAT targetability, 7 (15%) had a I-B targetability, 6 (13%) had a I-C targetability score and 10 (21%) were categorized as II-B. ERBB2 amplification, germline BRCA1/2 mutations, PIK3CA mutations, and ESR1 mutation were mainly classified as tier I-A based on randomized trials demonstrating the effectiveness of approved targeted therapies in patients with these alterations. By contrast, RET fusions, NTRK fusions, high-tumor mutational burden and microsatellite instability were ranked as tier I-C and somatic BRCA mutations, germline PALB2 mutations and HER-2 mutations as II-B. Six trials (14%, 6/42) supporting drug approval demonstrated substantial ESMO-MCBS clinical benefit. Overall, 6 recommendations (14%) had high-benefit genomic-based cancer treatments.

Conclusions: Fewer than one-fifth of molecular-targeted cancer therapies recommended in NCCN guidelines for metastatic breast cancer demonstrated substantial patient benefits. Value frameworks like ESCAT and ESMO-MCBS can help stakeholders identify therapies with the greatest potential.

Citation Format: Ariadna Tibau, Thomas J. Hwang, Jerry Avorn, Aaron Kesselheim. Clinical Value of Molecular Targets and Genome-Targeted Cancer Therapies Recommended by the National Comprehensive Cancer Network for Advanced Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-10-08.