The real impact of checkpoint inhibitors is not as hoped

Cristina Ferrario

It seems that the big revolution linked to the introduction of checkpoint inhibitor drugs is still far to come. According to estimates recently published in JAMA Network Open, only a small percentage of patients eligible for these treatments respond to them, at odds with great – and probably unrealistic – expectations generated about this way of treating cancer. “If FDA-approved checkpoint inhibitor drugs are universally available, we estimated that the proportion of US patients with cancer who could be eligible for such drugs is approximately 44%, while approximately 13% have a response to these drugs” Alyson Haslam and Vinay Prasad, Oregon Health & Science University, wrote.

As a matter of fact, cancer checkpoint inhibitors were shown to have the ability to generate durable responses in many so far untreatable neoplasms and to improve overall survival in randomized trials. And there’s an impressive wave of scientific and economic interest on these drugs, with a 600% increase in clinical trials using PD-1 and PD-L1 between 2015 and 2017 and a similar growth expected for the market, from $1 billion dollars in 2013 to $7 billion dollars in 2020.

Despite this scenario, no empirical analysis has been made of the potential use or benefit among all US patients with cancer.

That’s why the authors decided to focus on the 6 checkpoint inhibitors approved for 14 indications in the US from March 2011 to August 2018. The cross-sectional analysis found a big increase in the estimate percentage of US cancer patients eligible for checkpoint inhibitor drugs (from 1.54% in 2011 to 43.63% in 2018). The percentage of patients estimated to respond to these drugs also increased from 2011 (0,14%), but halted to 12.46% in 2018.

At the end of the day, figures remain modest, meaning that checkpoint inhibitors can help many patients, but don’t help a huge part of them. “Future research should explore biomarkers to maximize the benefit of immunotherapy among patients receiving it” authors concluded, hoping for an environment where patients can be honestly informed about treatments and can have realistic optimism, not being influenced by misleading rhetoric.

[Featured image: Healthy Human T cell (Photo by NIAID creative commons licence 2.0)]

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