Mesothelioma Clinical Trials: Eligibility May Be Too Strict, Study Finds

A new Australian study suggests that too many people are being left out of mesothelioma clinical trials under current trial rules. 

The researchers say that eligibility requirements around pleural mesothelioma studies are too strict. The result is that many people never have the opportunity to take advantage of investigational treatments only available through studies. 

In addition, the trial data gathered may not really apply to average mesothelioma patients. The Australian researchers are calling for changes that will let more people qualify for mesothelioma clinical trials. 

What Are Mesothelioma Clinical Trials?

Pleural mesothelioma is an intractable cancer of the lining around the lungs. People who get it usually worked in an industry that exposed them to asbestos. Once asbestos gets in the lungs, it stays there indefinitely. Exposed people can get sick 10 to 50 years later. 

There is no cure for mesothelioma. There are not even many good treatments. Mesothelioma clinical trials are the best hope for many patients. Human trials are the next step after laboratory and animal studies of new drugs or treatments. If preclinical data shows a treatment is safe and has promise, a clinical trial will test it in people. 

Studies consistently show that patients who participate in mesothelioma clinical trials live longer than those who have conventional therapies. Unfortunately, only a small percentage of mesothelioma patients take part in potentially life-saving studies. 

The Difficulty of Qualifying for Human Studies

The new Australian study focused on studies of two promising mesothelioma treatments. The trials involved bevacizumab (Avastin) or pembrolizumab (Keytruda). Avastin works by depriving mesothelioma tumors of a blood supply. Keytruda works by blocking mesothelioma cells’ ability to hide from the immune system. 

The large international Avastin trial for people with unresectable pleural mesothelioma went by the acronym MAPS. KEYNOTE-028 was a study of Keytruda for the same population. 

The Australian team evaluated 133 consecutive patients with unresectable pleural mesothelioma on their eligibility for either of these mesothelioma clinical trials. 

Half of the patients did not qualify for the MAPS trial. Thirty-seven percent of the patients did not qualify for the KEYNOTE-028 trial. The most common reasons were being 75 or older, not being able to perform everyday tasks, being on other medications, or having other health conditions. 

The patients who did quality for one of the mesothelioma clinical trials had an overall survival of 32.4 months. Overall survival for the rest of the patients was 20.5 months. 

The researchers say this highlights the need to get more regular patients into studies. They say allowing only the younger and healthier patients into mesothelioma clinical trials can skew the results. 

“Only ≤63% of our patients were eligible for these trials, highlighting the differences between real-world patients and the highly select trial population.,” writes lead author Brandon Lau of Chris O’Brien Lifehouse in the journal Clinical Lung Cancer. “Our patients who participated in clinical trials had superior OS, further emphasizing the selection bias in the trial population.”

For more information about clinical trials, CLICK HERE to visit the US government’s clinical trial database. 

Source:

Lau, B, et al, “Clinical Trials Eligibility of Patients With Malignant Pleural Mesothelioma: Use of Novel Therapies and Outcomes”, March 6, 2020, Clinical Lung Cancer, https://www.clinical-lung-cancer.com/article/S1525-7304(20)30007-3/pdf#%20