Most Targeted Cancer Drugs Lack Substantial Clinical Benefit

TOPLINE:

An analysis of molecular-targeted cancer drug therapies recently approved in the United States found that fewer than one-third demonstrated substantial clinical benefits at the time of approval.

METHODOLOGY:

• The strength and quality of evidence supporting genome-targeted cancer drug approvals vary. A big reason is the growing number of cancer drug approvals based on surrogate endpoints, such as disease-free and progression-free survival, instead of clinical endpoints, such as overall survival or quality of life. The US Food and Drug Administration (FDA) has also approved genome-targeted cancer drugs based on phase 1 or single-arm trials.
• Given these less rigorous considerations for approval, “the validity and value of the targets and surrogate measures underlying FDA genome-targeted cancer drug approvals are uncertain,” the researchers explained.
• In the current analysis, researchers assessed the validity of the molecular targets as well as the clinical benefits of genome-targeted cancer drugs approved in the United States from 2015 to 2022 based on results from pivotal trials.
• The researchers evaluated the strength of evidence supporting molecular targetability using the European Society for Medical Oncology (ESMO) Scale for Clinical Actionability of Molecular Targets (ESCAT) and the clinical benefit using the ESMO–Magnitude of Clinical Benefit Scale (ESMO-MCBS).
• The authors defined a substantial clinical benefit as an A or B grade for curative intent and a 4 or 5 for noncurative intent. High-benefit genomic-based cancer treatments were defined as those associated with a substantial clinical benefit (ESMO-MCBS) and that qualified as ESCAT category level I-A (a clinical benefit based on prospective randomized data) or I-B (prospective nonrandomized data).

TAKEAWAY:

• The analyses focused on 50 molecular-targeted cancer drugs covering 84 indications. Of which, 45 indications (54%) were approved based on phase 1 or 2 pivotal trials, 45 (54%) were supported by single-arm pivotal trials and the remaining 39 (46%) by randomized trial, and 48 (57%) were approved based on subgroup analyses.
• Among the 84 indications, more than half (55%) of the pivotal trials supporting approval used overall response rate as a primary endpoint, 31% used progression-free survival, and 6% used disease-free survival. Only seven indications (8%) were supported by pivotal trials demonstrating an improvement in overall survival.
• Among the 84 trials, 24 (29%) met the ESMO-MCBS threshold for substantial clinical benefit.
• Overall, when combining all ratings, only 24 of the 84 indications (29%) were considered high-benefit genomic-based cancer treatments.

IN PRACTICE:

“We applied the ESMO-MCBS and ESCAT value frameworks to identify therapies and molecular targets providing high clinical value that should be widely available to patients” and “found that drug indications supported by these characteristics represent a minority of cancer drug approvals in recent years,” the authors said. Using these value frameworks could help payers, governments, and individual patients “prioritize the availability of high-value molecular-targeted therapies.”

SOURCE:

The study, with first author Ariadna Tibau, MD, PhD, Brigham and Women’s Hospital and Harvard Medical School, Boston, was published online in JAMA Oncology.

LIMITATIONS:

The study evaluated only trials that supported regulatory approval and did not include outcomes of postapproval clinical studies, which could lead to changes in ESMO-MCBS grades and ESCAT levels of evidence over time.

DISCLOSURES:

The study was funded by the Kaiser Permanente Institute for Health Policy, Arnold Ventures, and the Commonwealth Fund. The authors had no relevant disclosures.

A version of this article appeared on Medscape.com.