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Is the Efficacy of Cancer Drugs Overstated?

 

By Jonathan Block

November 22, 2016

Is the Efficacy of Cancer Drugs Overstated?

The people chosen for clinical trials of cancer drugs are often not indicative of “real world” cancer patients, meaning some oncology medications that are currently on the market may exaggerate their efficacy.

That’s the argument from 2 oncologists, Sham Mailankody, MD, Memorial Sloan Kettering Cancer Center and Vinay Prasad, MD, Oregon Health & Science University. They argue that the majority of pivotal trials are conducted in cancer patients that are not representative of the overall cancer patient population.

Nearly 60% of cancer patients in the US are older than 65, and 31% are older than 75. But data from a 2012 study Mailankody and Prasad cite shows that in clinical trials of cancer drugs between 2007 and 2010, only 33% were older than 65 and just 10% were older than 75. During that time, 24 cancer drugs won FDA approval.

“Older patients in the real world experience more severe adverse effects of treatment and are more likely to halt or discontinue therapies, even those that are considered to be well-tolerated,” the pair write in JAMA Oncology.

As an example, they mention Nexavar (sorafenib), the only drug approved for hepatocellular cancer, a type of liver cancer. In its clinical trial, Nexavar extended median survival by 2.8 months, and was approved by the FDA in 2005.

However, an analysis of the drug’s efficacy since it has been on the market found that Nexavar was no better than best supportive care (treatment with no drugs designed to improve the patient’s quality of life) in terms of median survival. Why the dramatic change in efficacy from the pivotal trial? The average age of a patient in the “real world” analysis was 70 years old and a majority had other underlying health issues.

“Thus, older, sicker patients not only have poorer outcomes than those in the pivotal study but differences in demographics are so great as to transform a cancer drug with marginal effect into an ineffective drug,” Maliankody and Prasad write.

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Jonathan Block

Jonathan Block

Jonathan Block is MedShadow's content editor. He has previously worked for Psychiatry Advisor, Modern Healthcare, Health Reform Week and The Pink Sheet.
Jonathan Block

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Last updated: November 22, 2016