This release summarizes the preliminary results of an early Phase 1 safety trial using the drug pembrolizumab (marketed as Keytruda) in 22 patients with thyroid cancer that had not responded to chemotherapy. The study was presented at the large American Society of Clinical Oncology (ASCO) annual meeting as an abstract and has not yet been published in a peer-reviewed journal. While almost ignoring the safety aspect — the main purpose of a Phase 1 study — the abstract and release tout a 9.1 percent “overall response rate” among the six patients that completed the trial. Of the six completing the trial, two had a partial response. We think these results are too preliminary and based on too small of a group to warrant a news release calling Keytruda “promising” for advanced thyroid cancer. The release also omitted mention of the trial funders and the financial ties that exist between the investigators and the drug manufacturer.
This study of a new drug for treating thyroid cancer is part of a wider area of research into immunotherapy, in which drugs target mechanisms of the human immune response. This drug is an example of targeted chemotherapy which is becoming more important as treatments can be fine-tuned to the cancers of individual patients.
In patients with intractable cancers, immunotherapy appears to offer some new hope while also bringing sobering questions about affordability and disparity of access by income. The drugs are typically very expensive — with some estimates putting the treatment cost for a single patient as high as $1 million.
The release doesn’t mention cost. Immunotherapy drugs like Keytruda that are already on the market have received wide attention specifically because of their high prices..The cost of Keytruda is easily obtainable and is approximately $5,000 per 50mg single use vial. Although the dose was 10mg every two weeks, that would require two vials at approximately $10,000 per month drug costs or $240,000 for the two-year treatment program.
The news release used careful language when describing the limited benefits seen in this Phase 1, safety oriented clinical trial. We appreciate the fact that this is not a journal article, but an abstract presentation for a conference. But we think that readers deserved a bit more information
“At the time we reported our results, six of the 22 patients remained on treatment. Of those who completed therapy, two patients had a partial response for an overall response rate of 9.1 percent, and there was a stable disease rate of 54.5 percent. The six-month overall survival rate was 100 percent and the six month progression free survival rate was 58.7 percent.”
That being said we are not provided with any information about the expected stable disease rate or progression-free survival rate in untreated patients. While the stable disease and progression free survival rates were provided, the reader has nothing to compare them to.
There is one sentence related to harms in the release, but it doesn’t tell us what they are.
“There were no treatment-related deaths or therapy discontinuations due to drug-related adverse effects.”
The package insert lists the most common side effects as fatigue, cough, nausea, diarrhea, constipation, anorexia, arthralgia (joint pain), pruritus (severe itching), and rash.
The release is clear about the early phase use of this drug in a small number of patients.
There is no disease mongering. However, the release notes: “…the chance of being diagnosed with thyroid cancer has risen rapidly in the United States in recent years. This appears to be due to increased use of technology to detect thyroid nodules that may not otherwise been found previously.” But, no absolute numbers are provided. How many people are diagnosed? How has the rate changed in the last ten years? What are the implications of improved detection? Although there is no outright disease mongering, the reader is left with an incomplete picture of the relative risks of the disease.
The release contains no description of funding sources or conflicts. Of the multiple authors, the link to the abstract (click the blue words “abstract disclosures”) identifies many connections to Merck which manufactures pembrolizumab.
The release does not mention or compare any of the alternatives. According to Cancer.Net, approved treatments (depending on the type and stage of the thyroid cancer) include surgery, hormone treatment, radioactive iodine, external-beam radiation, chemotherapy and other therapies that target the immune system.
The release makes it clear that pembrolizumab is under study in an early clinical trial. It does not, however, point out that the drug is in fact commercially available under the trade name Keytruda, a drug we have heard a great deal about in the past few months related to its use in melanoma.
The release clearly states this was the first time the drug was administered to thyroid cancer patients.
The release doesn’t engage in unjustifiable language.