Novartis Says Swine Flu Virus Gives Poor Harvest for Vaccine

Novartis AG said the virus it’s growing to make a vaccine against pandemic flu doesn’t yield much of the antigen needed to protect people.

Lab workers are harvesting one dose or less of the component they need from each egg in which the virus is grown, said Eric Althoff, a spokesman for the Swiss drugmaker. That’s between a third and half of the typical yield for a seasonal flu vaccine, he said.

The low yield may slow production of a pandemic vaccine because it means drugmakers like Novartis, Baxter International Inc., Sanofi-Aventis SA and GlaxoSmithKline Plc can extract less of the protective ingredient from each egg. Baxter’s Chief Executive Officer Robert Parkinson and a spokesman for Sanofi also said yesterday the amount of swine flu virus growing in each egg is lower than for seasonal flu.

The World Health Organization, whose labs supplied the virus to drugmakers, is trying to produce samples that yield more antigen.

“There is work ongoing to improve them,” Novartis Chief Operating Officer Joerg Reinhardt said yesterday on a conference call. “But it’s very difficult to predict what it will be at the end.”

The H1N1 virus, also known as swine flu, is sweeping the southern hemisphere as tens of thousands of patients test positive for the virus in Australia, Argentina, Chile and other countries. It’s also spreading in the north outside of the usual flu season. The U.K.’s most senior doctor yesterday said the health service is planning for 65,000 deaths from the disease, which has claimed 429 lives worldwide.

‘Bad Yielder’

“The industry at large is challenged,” Baxter’s Parkinson said yesterday.

Most manufacturers make flu vaccines by injecting chicken eggs with an approved version of the virus to provide it with nutrients to grow and multiply. The amount of virus that grows in the egg and can be turned into shots is called its yield.

All government vaccine orders include a set yield assumption, Andrin Oswald, who heads Novartis’s vaccine unit, told reporters yesterday. One egg will usually produce enough antigen to make two doses of seasonal flu vaccine, according to Oswald.

“It is well known that some strains are good yielders, and some strains are bad yielders,” Marie-Paule Kieny, director of the WHO’s Initiative for Vaccine Research, said in a teleconference on July 13.

“Unfortunately we didn’t come up with a good yielder in the first series of strains,” she said. “To remedy that, the WHO laboratory network is again trying to generate new vaccine viruses” from patients who have been infected. “We hope that one of them will be giving higher yields, comparable to the ones obtained with seasonal vaccines.”

Kieny said the existing strain still allows drugmakers to make a vaccine, test it and submit it to regulators while the WHO hunts for a more promising seed virus.

Vaccine Revenue

The yield also determines the shot’s potential revenue. Novartis swine flu vaccine sales could be worth between $1 billion and $1.5 billion if a single dose is sold for $10, Karl Heinz Koch, an analyst at Helvea SA in Zurich said in a note to clients today. Novartis has not added this revenue to the current sales outlook, Chief Financial Officer Raymund Breu said on a conference call yesterday.