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* 32 percent response rate in patients treated with Opdivo
* 95 percent of responders still benefiting after 6 months
* Lung cancer results with Opdivo expected later in year (Adds detail on forthcoming lung cancer study findings)
By Ben Hirschler
MADRID, Sept 29 (Reuters) - Bristol-Myers Squibb's immunotherapy drug Opdivo produced markedly improved responserates with fewer toxic side effects compared to chemotherapy ina major melanoma study, underscoring its potential as a newtreatment option.
The data has been keenly awaited since this is the firstpresentation of results from a pivotal Phase III clinical trialof a promising new class of drugs designed to help the body'sown immune system fight cancer.
In the study, involving people with advanced melanoma, 32percent of patients saw their tumours shrink when given Opdivoagainst 11 percent of those treated with conventionalchemotherapy drugs.
Importantly, the duration of response was also much longer.Patients on chemotherapy typically responded for 3.6 months,whereas 95 percent of those who responded to Opdivo were stillbenefiting after six months and the median duration of responsewas not reached.
Patients in the study had previously been treated with thecompany's Yervoy immunotherapy, which works in a different wayto take natural brakes off the immune system.
"I was very nicely surprised," said Jeffrey Weber of theMoffitt Cancer Center in Florida, who presented the results atthe European Society of Medical Oncology annual congress onMonday.
"A 32 percent response rate with the majority staying inremission past six months is probably going to turn into a veryimpressive level of survival," he said. "I hope this is thedeath knell for chemotherapy in melanoma."
Opdivo, or nivolumab, is part of a promising new class ofdrugs designed to block a protein known as Programmed Deathreceptor (PD-1), or a related target known as PD-L1, used bytumours to evade the immune system's disease-fighting cells.
Industry analysts are waiting next to see how Opdivoperforms in another Phase III trial in lung cancer, for whichthey expect results in the fourth quarter of 2014. Sincenon-small lung cancer is a much bigger market than melanoma,that trial is viewed as critical to the drug's commercialoutlook.
Some investors are nervous about Opdivo's lung cancerprospects but Weber, for one, is upbeat. "It is highly likelythat the lung data will be positive," he told Reuters.
Opdivo became the first PD-1 inhibitor to receive regulatoryapproval anywhere in the world in July when Japanese regulatorsgave it a green light, although it has been beaten to market inthe United States by Merck & Co's rival Keytruda, whichwas approved earlier this month.
On Friday, Bristol-Myers said the U.S. Food and DrugAdministration had granted Opdivo a priority review and adecision on approval was due by the end of March.
Companies such as Roche and AstraZeneca arealso developing PD-1 pathway drugs for a variety of cancers,including lung cancer. Some analysts expect the new class couldgenerate more than $30 billion in annual sales worldwide by2025. (Editing by Michael Urquhart, editing by Louise Heavens)
