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Keytruda and colon cancer: coverage of benefits not balanced with harms and cost info

Merck Drug Helps Colon Cancer Patients With DNA Repair Defect

Our Review Summary

colon cancerThis Bloomberg report was about an ongoing phase II clinical trial that looked at the effectiveness of an immune system-triggering drug in colon cancer patients with specific genetic mutations.

The story conveys the most up-to-date information possible on the study and earns a pass (with some caveats) on the majority of our criteria. However, there is room for improvement in several areas that we highlight below in the review. For example, the story addresses how many patients experienced tumor shrinkages or immune responses, but doesn’t clarify what that means in terms of meaningful health outcomes for patients — things like survival and quality of life. Also, the story could have pointed out the study’s limitations, provided more thorough information on potential harms, and discussed costs and availability. This drug, Keytruda, is approved for treatment of melanoma and is available off label for colon cancer patients. It is very expensive.


Why This Matters

Keytruda is a cancer immunotherapy that is used to treat advanced melanoma when the tumor(s) cannot be removed by surgery. The drug is normally given after all other cancer therapies have failed. In September 2014, it was approved by the US Food and Drug Administration (FDA) on an “accelerated” basis and was recently shown to be beneficial in the treatment of lung cancer. Studies that can demonstrate additional benefits in colon cancer or other cancers with this specific type of genetic mutation would certainly be newsworthy, especially since colorectal cancer is the second leading cause of cancer-related deaths in the US for men and women combined.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

Despite the fact that Bloomberg Business delivers market and business news, there is no mention of cost in this article. Keytruda by Merck is thought of as a specialty medication, which means it is quite expensive. The drug has previously been estimated to cost $12,500 per month of treatment.

Also, broad genetic testing to identify mismatch repair deficiencies that can be treated with this drug will not come cheap. There’s no mention of how much the test costs and whether it is covered by insurance.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


Since the phase II clinical trial is ongoing, the article uses the latest numbers that were presented at the American Society of Clinical Oncology, rather than the figures that were published in the New England Journal of Medicine.

The story reports the absolute number of patients who experienced differences in their tumor sizes or responded to treatment. These are useful statistics, especially since the story highlights the dramatic difference in response rates between those with and without mismatch repair problems. Clearly, something’s happening in the patients with those mutations that isn’t happening in the other patients.

So we’ll award a Satisfactory rating here. But as noted below under the Quality of Evidence criterion, we think the story needed more detail on how these outcomes were defined and the fact that they were surrogate endpoints, which don’t always translate to real health benefits for patients.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

“Side effects of the drug include thyroid disorders and rashes,” the story says, but we think that description is insufficient. The number of patients with these side effects is not mentioned, nor is the severity of the reactions. And these were far from the only adverse events observed in the study. In fact, some 41% of patients had grade 3 (severe) or 4 (life-threatening) reactions!

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

Bloomberg misses the mark on a few points. First of all, it reports on the immune response to the drug and also tumor shrinkage. But how was that response measured? And if a patient responds to a drug, how does this affect a more meaningful health outcome like increased survival? What was needed is some acknowledgment that these are surrogate endpoints, which may or may not translate to meaningful health outcomes. The original study reported on survival statistics that could have been covered by the story to address this.

Another limitation that Bloomberg didn’t touch on is that the median follow-up time in this study was just 36 weeks. That means researchers can’t be sure whether the perceived benefits will stand the test of time.

Lastly, while the story notes that the study was small, it doesn’t explore the implications of this limitation. The researchers themselves called the study a “proof of principle” in a related news release and cautioned that larger studies are needed before clinical use.

Does the story commit disease-mongering?


The story does not engage in disease mongering. In the second paragraph, it explains how mismatch repair deficiencies could lead to various cancers, including colon cancer, and describes the small percentage of cancers affected.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

The independent source is Leonard Saltz, a gastrointestinal oncologist at Memorial Sloan Kettering Cancer Center in New York. He sheds light on why the study is important, how immune therapy drugs may work on these tumors, and what future studies may entail.

However, the article doesn’t mention any funding sources, which is always important to know in medical research stories. In this study, funding sources included Johns Hopkins University, philanthropic foundations and the National Institutes of Health’s National Cancer Institute.

The story also doesn’t note that one of the coauthors on the study was a Merck employee and that several coauthors disclosed relevant financial relationships with Merck and other companies. The lack of disclosure for these relationships tips us over the line to a Not Satisfactory rating.

Does the story compare the new approach with existing alternatives?


The report mentions that Merck’s main competitor is Bristol-Meyers Squibb’s Opdivo, which is also approved for melanoma, as well as lung cancer.

It would have been better if the article had also listed the traditional treatments for colon cancer, which include surgery, radiation therapy and chemotherapy. It would have also been helpful to know that Keytruda was given to patients with advanced cancers who were no longer responding to these standard therapies.

Since the article mentions at least one alternative to the immune system-triggering drug, we rate it Satisfactory on this criterion, with suggestions for improvement for next time.

Does the story establish the availability of the treatment/test/product/procedure?


The article states Keytruda is approved by regulators for the treatment of advanced melanoma, meaning this drug is likely available off label for colon cancer patients. But the story could been more explicit in its explanation. Again, we’ll give the story the benefit of the doubt.

Does the story establish the true novelty of the approach?


The piece makes it clear early in the story that this is the first indication that immune therapy drugs could also work for colon cancer patients with mismatch repair problems. Merck’s Keytruda is normally used for the treatment of advanced melanoma.

Does the story appear to rely solely or largely on a news release?


The article does not seem to be based on press releases we found online, like this one by Merck or this one put out by Johns Hopkins University. It includes an expert comment suggesting original reporting.

Total Score: 6 of 10 Satisfactory


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