(Bloomberg) -- Lung cancer treatment is moving beyond chemotherapy, with Merck & Co. setting the pace in a new category of therapies that harness the body’s immune system to fight tumors. 

The U.S. drugmaker’s drug Keytruda reduced the risk of death or cancer progression by 50 percent, Merck said, unveiling details of a crucial study at a meeting of the European Society for Medical Oncology. The medicine gave patients an average of 10.3 months before their cancer progressed, compared with six months on chemotherapy. Unlike competitor Bristol-Myers Squibb Co., whose similar drug Opdivo failed in an advanced trial and caused its stock to plunge, Merck selected patients who harbored high levels of a protein thought to predict how well the immune-system drugs will work.

The results give Merck a head start -- and not just on Bristol-Myers. Roche Holding AG and AstraZeneca Plc are also in the race for the best new immune therapy against lung tumors, the most common cancer in the world. Doctors will probably start testing patients soon after diagnosis to see whether they’re suited to treatment with Keytruda and can forgo the many side effects of chemotherapy, said Stefan Zimmermann, a chief oncologist at the Cantonal Hospital of Fribourg, Switzerland.

“The main reaction will actually be relief and renewed hope,” Zimmermann said on Sunday from the meeting in Copenhagen. “We have been waiting for ways to ditch the good old chemotherapy that carries significant toxicity.”

Patient Selection

The U.S. Food and Drug Administration is set to decide by Dec. 24 whether Keytruda, already approved for patients whose lung cancer got worse after chemotherapy, can be used as an initial treatment too. Some 224,000 Americans will probably be diagnosed with lung tumors this year, according to the National Cancer Institute.

Much of the battle for dominance in lung immune-oncology drugs thus far has centered on whether patients need to show high levels of a protein called PD-L1 to benefit. Merck’s trial focused on patients whose tumors expressed PD-L1 at least half the time. That group could comprise as many as one-quarter of newly-diagnosed lung-cancer patients, said Sam Fazeli, an analyst with Bloomberg Intelligence.

Combination Tests

By contrast, Bristol-Myers’s competing therapy, Opdivo, failed a test as a sole treatment for lung cancer after the company included patients with lower levels of PD-L1. But details of the trial unveiled at the conference pointed to lackluster results even in a narrower group of patients with high PD-L1 levels.

“PD-L1 assessment has to be part of the standard diagnostic workup,” said Corey Langer, director of the thoracic oncology program at the Abramson Cancer Center at the University of Pennsylvania. “Patients can’t wait for these results.”

Langer led a smaller trial of Merck’s Keytruda also presented in Copenhagen, which combined the drug with chemotherapy and also let in all patients, no matter their PD-L1 levels. The combination was almost twice as successful at shrinking lung cancer tumors than a standard chemotherapy regimen. But with just 123 patients, the trial was too small to say for sure whether the combination is better than immune therapy alone, Langer said.

Roche also presented results showing its immune therapy contender, Tecentriq, helped patients whose lung tumors had already progressed. Tecentriq was approved by regulators in May for advanced bladder cancer, and Roche expects a ruling from the FDA in second-line lung cancer by the end of next week. Results for newly-diagnosed patients aren’t expected before 2018, however.

By then, Fazeli said, investors will be focusing on combination therapies. The first results from two immune therapies used together will probably come next year from AstraZeneca. Bristol-Myers is also working on such a combination, with data due out in 2018. Like Merck, Roche is combining its immune-oncology drug with chemotherapy, aiming for approval in 2018.

“Given the data you see here with Keytruda alone, the combinations should by logic and by data seem to do better,” Fazeli said.

(Corrects FDA decision date in fifth paragraph.)

--With assistance from Jared S. Hopkins and Ketaki Gokhale To contact the reporters on this story: Naomi Kresge in Berlin at, Allison Connolly in London at To contact the editors responsible for this story: Chitra Somayaji at, Marthe Fourcade

©2016 Bloomberg L.P.