The Dangers in Directly Comparing Clinical Trial Results in the Era of Precision MedicineASCO Checkpoint Inhibitor Battle Between Merck and Roche Highlights the Pitfalls in Directly Comparing Clinical Trial Results in the Era of Precision Medicine

ASCO is always interesting for that hits the headline. 

This year has been no different. Several commentators have pointed towards Merck’s apparent upstaging of Roche with their clinical trial results for their PD1/PD-L1 checkpoint inhibitors for previously untreated squamous non-small cell lung cancer patients.

On Saturday Roche announced clinical trial results for Tecentriq, that in combination with chemotherapy led to a 29% reduction in risk of the disease worsening or death compared to chemotherapy alone.

On Sunday Merck announced clinical trials results for Keytruda, that in combination with chemotherapy led to a 36% reduction in risk of death, enhancing overall survival rates significantly. The reduction in the risk of the disease worsening was 44%, and the risk of death down 35% (in the ‘like-for-like’ comparisons with Roche).

Given these results (particularly Merck’s overall survival stats), as well as Merck’s track record in the non-small cell lung cancer market and Keytruda’s existing approval for other indications, it would be easy to proclaim Merck as the clear winner. And at this stage, that is undoubtedly the case.

But not so fast.

Not only is Tecentriq’s overall survival data not expected until September, several other studies are underway – important studies that will shed more light on which sub-sets of patients Tecentriq may work better for.

FiercePharma also reported a quote from Dan Chen, VP and Global Head of Cancer Immunotherapy Development at Roche’s Genentech, who pointed out, there were, “a lot differences in the way the trials were run”. They also reported Merck agreeing, with Roy Barnes, their Head of Global Clinical Development, commenting, “there are all sorts of risks in doing cross-trial comparisons, not least of which” is that patient populations were not exactly the same.


Merck’s experience in successfully taking Keytruda through clinical trials for other lung cancers may also have come into play in helping to explain the better results. The lessons learned in successfully taking similar drugs to market cannot be underemphasized, not least the specific steps taken to optimize results.

In the new era of precision medicine, clinical trial results are not so easy to interpret at first glance. This is a fact that both commentators and the market at large have yet to fully adjust for. The old days of “one-size-fits-all” are over in oncology. It’s entirely possible that Tecentriq delivers better results that Keytruda is specific sub-sets of patients. Something Roche will be keen to demonstrate in the coming months. We shall see.

Whatever happens, positive trial results in this area are great news for patients. New and better treatments for lung cancer are sorely needed.