How Many Patients in Early Cancer Trials Receive Treatments That Gain FDA Approval?

Clinical trials are scientific studies providing critical data on the safety and efficacy of medical treatments and are a cornerstone of modern medicine. Drug development typically takes an average of 10-15 years , and bringing a new drug into patient use requires an investment of approximately 2.6 billion dollars .

Cancer clinical trials are vital in this context because they offer new hope for patients with cancers that do not respond to standard treatments . This article discusses a new analysis examining how many patients enrolled in phase 2 cancer trials received a treatment that subsequently obtained FDA approval.

A New Study

Clinical trials consist of phases 1, 2 and 3, collecting data on drug dosage, safety and efficacy. JNCI: Journal of the National Cancer Institute published a new analysis on 25 February 2025 showing that, among patients in phase 2 clinical trials, approximately 1/6 (16%) received a treatment that was ultimately approved by the FDA.

When drugs recommended by the US National Comprehensive Cancer Network (NCCN) for use in other indications were included, the proportion rose to 1/5 (20%), while the figure fell to 1/11 (9%) for treatments considered to offer clinically meaningful benefit.

Study Details

Phase 2 cancer trials allow patients to try promising new treatments. However, it is unclear how many of these treatments receive FDA approval and whether patients actually obtain access to approved treatments.

Previous studies had found the corresponding proportion in phase 1 clinical trials to be 1/83 .

In this new analysis, among studies launched between November 2012 and November 2015, 400 phase 2 cancer trials were randomly selected. Together, these studies involved more than 25,000 patients in 608 treatment cohorts testing the efficacy of 332 different drugs.

Primary objective: Whether patients in phase 2 clinical trials received a treatment regimen that subsequently obtained FDA approval, termed thetherapeutic proportion .

Secondary objective: In addition to FDA approval, the analysis considered NCCN-recommended off-label uses and the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS) criteria for identifying drugs providing substantial clinical benefit.

Results

• Among participants in phase 2 clinical trials, 4045 patientsreceived a regimen that subsequently gained FDA approval. This corresponds to a therapeutic proportion of 16.2% .

• Including treatments recommended for off-label use by NCCN raised the proportion to 19.4% .

• Considering treatments providing clinically meaningful benefit reduced the proportion to 9.3% .

• Of participants, 32.5% enrolled in a trial testing a drug that progressed to phase 3.

• Biomarker use, a trial including immunotherapy, a larger phase 2 cohort, or an industry-sponsored nonrandomized studywas associated with a higher therapeutic proportion.

What Does It Mean for Clinical Practice?

The authors state, "When a patient enrolls in a phase 2 clinical trial, the chance of receiving a treatment that will subsequently be approved is approximately 1/6."

Compared with the proportion previously reported in phase 1 studies, 1/83, phase 2 trials substantially increase the proportion of patients obtaining access to an FDA-approved treatment.

In an accompanying editorial, Dr. Howard S. Hochsterof Rutgers Cancer Institute suggests that the therapeutic proportion is probably underestimated. "If drugs receiving FDA approval for any indication and dose are included, the proportion of patients benefiting rises to 38% . Including treatments incorporated into NCCN guidelines raises this proportion to 51% ," he adds.

Limitations

Because the study focused on phase 2 clinical trials from 2012-2015, it may not fully reflect current drug development trends. Furthermore, because cytotoxic drugs were excluded from the analysis, the actual proportions benefiting may differ.