British pharmaceutical giant GlaxoSmithKline said Monday it was "urgently" investigating how to boost production of its antiviral drug Relenza in response to the international swine flu outbreak.
The company has already provided 100,000 packs of the drug to Mexican authorities, along with a further 170,000 doses of its seasonal flu vaccine, and was discussing with Mexico whether further help was needed, it said.
Swine flu has been blamed for dozens of deaths in Mexico over the past month and on Sunday the United States declared a health emergency amid signs the disease was spreading.
"GSK is continuing to discuss with the Mexican authorities whether further support from GSK is needed at this time," a GSK statement said. "In addition, GSK is urgently assessing mechanisms to increase production of Relenza."
The US Centers for Disease Control and Prevention (CDC) said Monday that Relenza and Tamiflu, which is produced by the Roche pharmaceutical company, are effective in fighting the strain of swine flu that has world health authorities on high alert.
"Laboratory testing on these swine influenza A (H1N1) viruses so far indicate that they are susceptible (sensitive) to oseltamivir and zanamivir," the medical names of Tamiflu and Relenza, the CDC said.
Roche, which manufactures Tamiflu, has delivered the anti-viral already held in Mexico to the authorities and topped up local stocks with a fresh shipment over the weekend, Terence Hurley, a spokesman for the pharmaceutical company said.
Rolling out a vaccine against the strain of swine flu that has health authorities around the world on a high state of alert would take drug companies "a number of weeks," GSK spokesman David Outhwaite told AFP.
"The challenge with these flu viruses is that they come in many different guises and they change all the time," he said.
World Health Organization officials warned Sunday that the new strain, apparently born when human and avian flu viruses infected pigs and became mixed, could mutate further.