Portola Pharmaceuticals Inc. said its partner Novartis AG will begin final-stage testing of the experimental blood thinner elinogrel after researchers found it worked quickly in patients who had surgery to unblock an artery.
Elinogrel took effect within a half hour to keep the blood’s platelets from sticking together and forming a clot, researchers who conducted an earlier study said at the European Society of Cardiology conference in Stockholm. The drug left patients at a higher risk of bleeding requiring medical attention and liver complications than the standard therapy of Sanofi-Aventis SA and Bristol-Myers Squibb Co.’s Plavix.
The 29-month final trial will start next year and differ from the previous study by testing only oral use in stable heart disease patients, said William Lis, chief executive officer of South San Francisco, California-based Portola, in an interview in Stockholm. Researchers won’t know how elinogrel compares to other blood thinners until that trial is finished, said Robert Harrington, a professor of medicine at Duke University and the chairman of the earlier trial’s steering committee.
“We seem to be able to match the biology, the platelets and the bleeding,” Harrington said in a telephone interview in Stockholm. “Now what you’ve got to do if you really want to know is do a large-scale trial.”
Monitoring patients for liver side effects will be important, Harrington said.
Novartis shares rose 40 centimes, or 0.8 percent, to 53.70 Swiss francs at 4:30 p.m. in Zurich trading.
Today’s trial tested intravenous elinogrel against Plavix in the first 24 hours after elective surgery to widen a blocked artery. Patients were then given either an oral dose of the drug or Plavix for a two- to four-month follow-up.
There weren’t any statistically significant differences in the short- or long-term effectiveness of the two drugs at forestalling strokes and blood clots, Lis said.
The 24,000-patient final-stage trial will compare two doses of elinogrel with placebo in patients who are also taking aspirin, he said. The company is also considering whether to conduct another final-stage trial to test both intravenous and oral forms of the medicine in patients with acute coronary syndrome, Chief Medical Officer Daniel Gretler said. The condition, caused when plaque builds up in arteries and blocks blood flow, can lead to chest pain and heart attacks.
Novartis, based in Basel, Switzerland, licensed elinogrel from Portola in February 2009.
If approved, the compound may generate revenue exceeding $1 billion a year, said Karl Heinz Koch, a Zurich-based analyst for Helvea, in an e-mail. Elinogrel’s potential will depend not on how it matches up to Plavix, which faces generic competition in 2012, but to a newer anti-clot drug, AstraZeneca Plc’s Brilinta, which is under review by U.S. regulators, Koch said.