(Bloomberg) -- A combination of Johnson & Johnson and Genmab’s Darzalex with Celgene’s Revlimid plus a chemotherapy produced results that doctors said would alter the face of care for elderly and frail multiple myeloma patients. But, the treatment could cost more than $1 million dollars in the U.S., blocking widespread adoption, according to one analyst.

The latest Darzalex study showed deeper responses and longer remissions from the combination, and suggested it may offer better survival in patients who were ineligible for stem-cell transplants compared to the current standard treatment, a regimen including J&J and Takeda’s Velcade.

It’s clear patients getting the new regimen may survive another four or five years, Thierry Facon, a professor of hematology at Lille University Hospital in France and the lead author of the study, said at the American Society of Hematology meeting earlier this week in San Diego.

Price could be a problem for U.S. patients, Leerink analyst Geoffrey Porges wrote in a note to clients. The cost of the Darzalex-Revlimid cocktail over four years is roughly $900,000 “and is likely to pose a major barrier to adoption in many parts of the world,” as well as for some Americans, especially if those patients are living longer.

“Outside the U.S., drug prices are likely to be 20 to 40 percent lower than in the U.S., but the relative cost and value arguments over this regimen are still likely to occur,” Porges said. Meanwhile an even more potentially expensive combo is being examined. Darzalex- Velcade-Revlimid and chemotherapy is already being contemplated, although it would likely be used in either younger patients or elderly but still fit patients, Facon said.

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