Cancer drugs have one of the lowest success rates of any therapeutic area in clinical development. Only about 5.7% of cancer drugs that enter Phase 1 trials ultimately reach FDA approval, based on data from 2015 to 2023 published in Nature Communications. That means roughly 94 out of every 100 cancer drugs that begin human testing never make it to market. The entire process, from first-in-human trial to approval, typically takes 8 to 10 years.
How Cancer Compares to Other Diseases
Oncology has historically been one of the hardest areas in medicine to develop drugs for. When researchers tracked over 7,000 drug development programs, the success rate for cancer drugs moving from Phase 3 trials to an FDA application was about 40 to 45%. For all diseases combined, that same transition succeeded roughly 58 to 60% of the time. Cancer’s complexity, the genetic diversity of tumors, and the high bar for proving a drug extends survival all contribute to this gap.
Where Most Cancer Drugs Fail
Phase 2 is the graveyard. This is the stage where researchers first test whether a drug actually shrinks tumors or slows disease progression in a meaningful way, and it has consistently been the biggest bottleneck in cancer drug development. Phase 1 trials, which primarily test safety and dosing, have also become harder to pass in recent years, with success rates dropping from about 68% to 37% over time. Phase 3 trials, by contrast, have actually improved, climbing from a 37% success rate to nearly 58%.
The single biggest reason cancer drugs fail is that they simply don’t work well enough. An analysis of 640 Phase 3 trials found that 54% failed during development. Among those failures, 57% were because the drug couldn’t demonstrate adequate efficacy. Safety problems accounted for 17% of failures, and 22% failed due to lack of funding, a reminder that running out of money kills promising drugs too.
Blood Cancers vs. Solid Tumors
Not all cancers are equal when it comes to trial success. Blood cancers like leukemia and lymphoma respond far better to experimental treatments than solid tumors like lung, breast, or colon cancer. In Phase 1 trials, the response rate for blood cancers was 60.6%, compared to just 6.1% for solid tumors. The clinical benefit rate, a broader measure that includes patients whose disease stabilized, was 62.8% for blood cancers and 36.4% for solid tumors.
This difference reflects fundamental biology. Blood cancers are often driven by a single genetic mutation that a targeted drug can exploit. Solid tumors tend to be genetically diverse, with cancer cells evolving resistance and hiding within complex tissue environments that are harder for drugs to penetrate.
Biomarker Testing Has Changed the Odds
One of the biggest shifts in cancer drug development has been the use of biomarkers to select patients most likely to respond. Instead of testing a drug on all comers, researchers now screen patients for specific genetic mutations or protein markers and enroll only those whose tumors match the drug’s target.
This approach has a dramatic effect on success. Trials that use biomarkers to guide patient selection are nearly five times more likely to lead to an approved drug than trials without biomarkers. For lung cancer specifically, the benefit was roughly sevenfold. For melanoma, it was eightfold. Even trials using early-stage exploratory biomarkers, where the science is less established, showed a 4.6-fold improvement in approval likelihood. The one notable exception was colorectal cancer, where biomarker-guided trials didn’t show a statistically significant advantage.
Immunotherapy’s Impact on Survival
Immunotherapy, which works by helping the immune system recognize and attack cancer cells, has been one of the most successful classes of cancer drugs to emerge from clinical trials in the past decade. The first major breakthrough came in 2011 with an immune checkpoint inhibitor approved for advanced melanoma, followed by a second class of checkpoint inhibitor in 2014.
The real-world results have been striking. For patients with advanced melanoma, the 3-year survival rate rose from 22% in 2010 to 2012, before these drugs were widely available, to 34% in 2015 to 2017. That 12-percentage-point jump in just a few years represented a meaningful shift for a cancer that was previously considered nearly untreatable once it spread. Immunotherapy has since expanded to lung cancer, bladder cancer, kidney cancer, and many other types, though the degree of benefit varies considerably.
Why So Few Patients Participate
One underappreciated challenge is that very few cancer patients enroll in clinical trials. The overall participation rate for adult cancer patients in treatment trials is about 7.1%, up from an estimated 2 to 3% in the early 2000s. About one in five cancer patients (22%) participates in some form of cancer research, including observational studies, but the treatment trial number remains low.
This matters because small, homogeneous trial populations can make it harder to detect whether a drug truly works, and results may not reflect how a drug performs in a broader, more diverse group of patients. Geographic barriers, strict eligibility criteria, and lack of awareness about available trials all contribute to the low enrollment numbers. Trials that struggle to recruit enough patients also take longer to complete, adding years to an already lengthy development timeline.
What the Numbers Mean in Practice
A 5.7% overall success rate sounds dismal, but context matters. That figure includes every experimental drug that enters human testing, many of which are based on early scientific hypotheses that don’t pan out. The drugs that do make it through tend to offer genuine improvements. Modern trial designs, biomarker-guided patient selection, and advances in immunotherapy have all pushed the field forward, even if the raw success rate remains low.
For patients considering a clinical trial, the calculus is different from the drug developer’s perspective. Participating in a trial doesn’t mean a 5.7% chance of benefit. Many trials offer access to drugs that are already showing promising results in earlier phases, and participants receive close medical monitoring throughout. The low overall success rate reflects the difficulty of the science, not the odds for any individual patient walking through the door.