Merck cervical cancer virus vaccine performs well

Drugmaker Merck & Co. Inc. on Thursday said its investigational vaccine against a sexually transmitted virus linked to cervical cancer triggered a stronger immune response in young adolescents than in young women in a late-stage trial.

The trial of 1,529 people found that adolescent males and females aged 10 to 15 receiving the vaccine, called Gardasil, produced a significantly higher level of anti-viral antibodies, compared with young women aged 16 to 23, Merck said.

The vaccine aims to protect against strains of the sexually transmitted human papillomavirus (HPV), a cause of cervical cancer, which is the second-biggest killer of women worldwide.

Merck said the data from the Phase 3 trial builds on earlier studies in young women that found the vaccine cut incidence of infections, including cervical pre-cancers and genital warts.

As the first trial to look at young people ages 10 to 15 years old, the "bridging study" aims to extrapolate effectiveness of the treatment in the older group to the younger population based on immune responses, the company said.

"This is the first time we've gotten adolescent results," said Eliav Barr, head of clinical research for HPV vaccines at Merck. "What it means is that both kids as well as adults over the entire age range, almost all respond to the vaccine."

Merck, based in Whitehouse Station, New Jersey, is racing rival GlaxoSmithKline Plc, which is working on its own vaccine called Cervarix. Analysts believe the drugmakers are headed for a fierce marketing battle.

Three groups of patients were tested with the three-dose regime: males aged 10 to 15 years, females aged 10 to 15 years old, and females aged 16 to 23 years old.

Responses to the vaccine were measured by the level of anti-HPV antibodies in the blood.

Adverse events included higher rates of fever within 15 days among the younger patients.