Amgen, the world’s largest biotechnology company, is expected on Monday to launch an attack on the safety of an anaemia drug made by its rival Johnson & Johnson, the world’s second-largest pharmaceuticals concern.
It is unusual for drugs companies to attack each other’s products publicly. Amgen’s move is an attempt to distance itself from side effects linked to Eprex, a synthetic form of the human hormone EPO made by J&J, under licence from Amgen, which discovered it.
Amgen fears that the problem could threaten its two biggest selling products, which are almost identical to Eprex and accounted for more than half its $4bn revenues in 2001.
Eprex has been linked to a rare but devastating condition known as antibody-mediated pure red blood cell aplasia or PRCA. The condition is triggered when the body produces antibodies against its own EPO, shutting down red blood cell production. The only treatment for PRCA is regular, life-long blood transfusions.
Amgen will tell an international medical conference in Copenhagen that its versions of the drug, known as Epogen and Aranesp, are safer than Eprex.
The causes of PRCA are not clearly understood, but its incidence has risen sharply since 1998. Between July 1997 and December 2001 82 cases of PRCA were linked to synthetic EPO. Eprex was linked to 78 cases and Epogen to four.
Amgen also makes a fourth version of the treatment called Procrit, which is sold by J&J in the US. The EPO proteins in Procrit and Eprex are identical, but Procrit has not been linked with PRCA. That has led scientists to suggest differences in the way the two drugs are made may be responsible for the side effects.
Eprex is made by J&J’s Ortho Biotech subsidiary in Puerto Rico. Eprex and Procrit accounted for 10 per cent of J&J’s $33bn revenues in 2001.
Amgen said its first concern was patient safety. “It is devastating to suddenly have your life dependent on transfusions,” Amgen said.
“The outbreak of PRCA is due to Eprex. It is a product-specific effect, not a class [of drug] effect. Our case would be: Why put your patients at risk when there are other products available, not just from Amgen but from Roche as well,” the company said.
Ortho Biotech said it was investigating the problem and had written to warn doctors of the potential danger.
“Do we know why there are cases [of PRCA] with our product versus Amgen’s product or Roche’s product? No. Have we looked at manufacturing? Yes. We will continue to look until we get to the source. We are working closely with health authorities around the world,” it said.
The two companies have fought several court battles over the rights to EPO, but industry observers have been surprised at the public nature of their latest spat.