At the American Society of Clinical Oncology (ASCO) annual meeting over the weekend, Merck’s Keytruda continued its winning streak. 

In data presented at the meeting, the cancer immunotherapy was shown to improve survival when given on its own as a first-line treatment for newly-diagnosed lung cancer patients compared with chemotherapy. In a separate study, when combined with chemotherapy, the drug decreased the risk of death for patients with the hard-to-treat squamous form of non-small cell lung cancer compared to chemotherapy alone. 
These significant findings only add to the trove of positive data Keytruda has racked up in recent months, which, taken together, indicate it is an effective treatment for most advanced lung tumors. Bristol-Myers Squibb, Roche, and AstraZeneca all have similar drugs, but to date, the strength of Keytruda’s clinical trial results place it at the head of the pack.
This position hasn’t translated to sales. At least not yet. According to April U.S. commercial sales data from IQVIA and Symphony, Bristol-Myers’ immunotherapy drug Opdivo continues to outpace Keytruda. IQVIA data showed a tight race, with Opdivo bringing in $307 million for the month, compared to Keytruda’s $298 million. Data from Symphony indicated a larger gap, with Opdivo generating $342 million vs. Keytruda’s $276 million. 
Unsurprisingly, analysts don’t expect this dynamic to continue given Keytruda’s continued clinical trial dominance. “We expect this to soon change,” Credit Suisse analyst Vamil Divan wrote in an investor note last week. “We are not surprised by the April monthly sales data as we have assumed the commercial benefit for Merck from some of the recent Keytruda data in lung cancer will likely be seen later,” in the second quarter.
While the analyst noted he is “concerned about the longevity of Opdivo’s second line lung cancer sales,” Divan continued, the commercial impact likely won’t be felt until later this year and 2019, when patients who otherwise would have received Opdivo second-line treatment don’t because they’ve already been treated with Keytruda. He went on to predict Keytruda will make $4.2 billion in U.S. sales this year, ahead of Opdivo’s $3.7 billion. 
The reversal of fortunes is more dramatic for long-term projections. According to Forbes, analysts at J.P Morgan predict that in 2022, Keytruda will generate $8 billion in lung cancer sales, four times more than Opdivo’s $2 billion.