GlaxoSmithKline's AS04 adjuvant could lead to a longer immune response for the firm's investigational cervical cancer vaccine Cervarix than traditional aluminum adjuvants, the firm said July 12.

AS04 comprises aluminum salt plus monophosphoryl lipid A. Merck's recently launched Gardasil human papillomavirus vaccine uses an aluminum adjuvant.

A study to be published in the Aug. 14 issue of Vaccine compares patients treated with AS04-formulated Cervarix with patients treated with the same vaccine that was formulated with aluminum adjuvant. "Antibody levels and memory B cells were measured over a total period of four years," GSK said.

The results "showed that antibody levels induced by the HPV vaccine formulated with the AS04 adjuvant system were 1.5 to 2.1 times higher for HPV 16 and 18 respectively than those induced following vaccination with the aluminum formulation at four years."

Additionally, in the AS04 treatment group, "observed numbers of memory B cells were 2 to 3.6 times higher for HPV 18 and HPV 16 respectively than those observed with the aluminum formulation."

This could suggest "the potential ability of the AS04 adjuvanted vaccine to increase immune memory," the firm explained.

Merck's Gardasil was approved in early June for the prevention of cervical cancer, cervical pre-cancers, vulvar pre-cancers and vaginal pre-cancers caused by HPV types 16 and 18 as well as genital warts and low-grade cervical lesions caused by HPV types 6, 11, 16 and 18 (¹ Also see "Merck’s Gardasil HPV Vaccine Clears FDA" - Pink Sheet, 8 June, 2006.).

GSK has said that it expects to file Cervarix in the U.S. by the end of 2006; it is already pending in the EU. In February, Pharmaceutical Operations President David Stout said that the firm expects the key differentiator between the rival products to be the adjuvant (² Also see "Cervarix Reimbursement Will Be Key Challenge For Adoption, GSK Says" - Pink Sheet, 9 February, 2006.).

At last month's Goldman Sachs Global Healthcare Conference, GSK CEO J.P. Garnier further explained that although Merck had targeted its vaccine to HPV in men and women, Cervarix is specifically tailored toward prevention of cervical cancer in women.

-Kathleen Michael

Cervarix Adjuvant Could Provide Longer Cancer Immune Response, GSK Says

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