Cervical cancer drug war

THE foreign-made cervical cancer vaccine that will compete against Australian-developed Gardasil may prevent more cancers than the home-grown product, with new evidence showing it may protect women against other strains of the virus that causes the disease.

Gardasil, which was based on work by former Australian of the Year Ian Frazer, has proved to be 100 per cent effective in protecting women against types 16 and 18 of the human papilloma virus, which together are thought to cause 70 per cent of cervical cancers worldwide - and up to 80 per cent in Australia.

Gardasil is expected to reap hundreds of millions of dollars in royalties for CSL, which sells the vaccine in Australia and licensed it for worldwide sale through drug giant Merck.

However, interim findings from a large international study involving more than 18,000 women aged 15 to 25 - including about 500 women in Australia - has found that a rival vaccine, GlaxoSmithKline's Cervarix, not only protects against types 16 and 18, but also provides lesser protection against types 45 and 31.

Rachel Skinner, of the Vaccine Trials Group of Perth's Telethon Institute for Child Health Research, headed the Australian arm of the study. She said the other two types were responsible for a further 10 per cent of cervical cancers worldwide, although the equivalent figure in Australia was not known.

If the preliminary results are borne out, it may mean Cervarix could prevent more deaths than Gardasil. There are 750 new cases of cervical cancer each year in Australia, and 250 deaths.

Earlier this year, Gardasil began being provided to Australian schoolgirls under the National Immunisation Program. From Sunday, Gardasil will be made available free of charge to all women aged 18 to 26. GlaxoSmithKline has applied to have Cervarix also subsidised on the national scheme.

"The evidence of this broader protection (from Cervarix) is very exciting," Dr Skinner said.

"It more strongly suggests that this vaccine might ultimately be shown to provide broader protection against pre-cancerous lesions and cervical cancer, more than can be accounted for by (protection against) HPV 16 and 18 alone."

The latest findings, published online yesterday by The Lancet, were stronger confirmation of results published last year.

About half the 18,000 women in that study were randomly assigned to receive Cervarix, while the others received a hepatitis A vaccine. After 15 months, Cervarix was found to cut pre-cancerous lesions caused by HPV 16 and 18 by 90.4 per cent. Six-month persistent infections by HPV 45 were cut by 60per cent and for HPV 31 by 36 per cent.

However, Dr Skinner cautioned that it would be wrong to conclude that one vaccine was better than the other, saying Gardasil was also effective against two other strains of HPV, types 6 and 11, offering 90 per cent protection against genital warts. Cervarix has not been designed to protect women against those strains.

A spokeswoman for Gardasil's maker, Melbourne-based CSL, said several of the study's specific findings appeared to suggest a wide degree of uncertainty about the protection offered by Cervarix, and even opened the possibility that it might be less effective than Gardasil against some types.

"I'm not sure that this is such good news" for Cervarix, the CSL spokeswoman said.

source:www.theaustralian.news.com.au