Merck vaccine prevents cervical cancer
In what represents an enormous breakthrough, Gardasil, an investigational vaccine from Merck, has been proven to prevent 100% of high-grade cervical pre-cancers and non-invasive cervical cancers associated with human papillomavirus (HPV) types 16 and 18, the two most common forms of a virus linked to such cancers, killing around 300,000 women worldwide each year, following a phase III study.
In what represents an enormous breakthrough, Gardasil, an investigational vaccine from Merck, has been proven to prevent 100% of high-grade cervical pre-cancers and non-invasive cervical cancers associated with human papillomavirus (HPV) types 16 and 18, the two most common forms of a virus linked to such cancers, killing around 300,000 women worldwide each year, following a phase III study.
The trial, which tracked more than 12,000 women from 13 countries over an average period of two years, is part of an ongoing phase III programme for Gardasil involving over 25,000 people in 33 countries. It evaluated the incidence of HPV 16/18-related cervical pre-cancers known as CIN (cervical intraepithelial neoplasia) 2/3 and non-invasive cancers. CIN 2 is a moderate-grade lesion of the cervix; CIN 3 represents both high-grade lesions and CIS (carcinoma in situ), the immediate pre-cursor to invasive squamous cell cervical cancer. The analysis compared Gardasil (quadrivalent human papillomavirus types 6, 11, 16, 18, recombinant vaccine) to placebo in women who were not infected with HPV 16 and 18 at enrolment and who remained free of infection through the completion of the vaccination regimen. Women aged 16 to 26 years were randomised to receive a three-dose regimen of either Gardasil or placebo; 6,082 received Gardasil; 6,075 received placebo. There were 21 cases of lesions and early-stage cancers associated with the two virus types among those taking placebos.
Although the vaccine was completely protective against the two virus types, Laura Koutsky, a professor of epidemiology at the University of Washington and leader of the study, said she hopes the vaccine will eventually be improved to protect against up to another half dozen types of the virus that cause cervical cancer: 'in that case, you could be blocking viruses that cause 87% of cervical cancer cases, instead of 70%'.
It plans to seek US FDA approval for the cancer vaccine, which also protects against another two types of the virus that cause genital warts, in the fourth quarter of 2005, and is partnering the vaccine in Europe with Sanofi-Aventis.
Merck's earnings suffered after the withdrawal in 2004 of its Vioxx arthritis drug, and it faces further losses with the prospect of thousands of lawsuits from former Vioxx users and their families who claim that the drug caused heart attacks and other serious health problems. Gardasil has thus provided a well-needed pick-me-up, with industry analysts saying that it could generate peak annual sales of over $2bn. Shares of Merck have risen 2% (53 cents) to $27.42 on the New York Stock Exchange following the announcement.