Gardasil

Gardasil is a quadrivalent vaccine developed by Merck for prevention of cervical cancer in women by preventing infection from four strains of the human papillomavirus (HPV), the most prevalent sexually transmitted disease.

The vaccine targets four types of HPV: 16, 18, 6, and 11. HPV types 16 and 18 account for about 70% of HPV-related cervical cancer cases. HPV types 6 and 11 are responsible for 90% of genital wart cases.

Biotechnology

The vaccine is made using recombinant technology. Viral capsid genes from HPV 6,11,16, and 18 are inserted into plasmids and multiplied. These particles are then self-assembled into viral-like particles that appear similar to the HPV virions but lack their DNA and RNA. Thus these agents are not infectious and cannot induce cancer. They do, however, trigger an antibody response that protects the individual from futures exposures to the specific HPV types.

Indications

Clinical trials showed Gardasil prevented 100% of cervical cancer cases related to the two HPV strains in women who had not been previously infected, Merck said. Gardasil also has prevented 99% of the genital warts cases that were caused by HPV types 6 and 11.

Gardasil also may be used in preventing HPV 16/18-caused anal cancer. An HPV vaccine - what it might really mean, Edwin J. Bernard, AIDSmap, October 24, 2005 (Accessed June 8, 2006) A 2005 study in San Francisco found that 95 percent of HIV-infected gay men also had anal HPV infection, of which 50 percent of had precancerous HPV-caused lesions. HAART is not reducing risk of anal cancer in gay men, Edwin J. Bernard, AIDSmap, August 29, 2005 (Accessed June 8, 2006)

Administration

After undergoing extensive clinical trials, Gardasil was approved by the Food and Drug Administration (FDA) on June 8, 2006, and scheduled to be available by the end of June.FDA approves cervical cancer vaccine, AP, accessed June 8, 2006

Gardasil is given in 3 injections over 6 months, namely at enrollment, and 2 and 6 months later.

Adverse events could be local limited reacions at the site of injection, such as pain, swelling, redness, and itching.

On June 29,2006, a panel of experts, the Advisory Committee on Immunization Practices, gave their approval for the vaccination of Gardasil on children as young as 9 years old. They also recommended that the vaccine be included in the federal Vaccines for Children Program, which would provide the vaccines free of charge to children under the age of 18 who are uninsured. Panel approves Gardasil usage, AP, accessed June 30, 2006

Long term impact

One unknown property of the vaccines now being researched is their longevity. Since the studies have been of short duration, it is unknown whether the vaccines will last just a few years or for much longer. Further study over time is required to answer this question.

270,000 women died of cervical cancer worldwide in 2002.Cohen J. 2005. High Hopes and Dilemmas for a Cervical Cancer Vaccine. Science, 308(5722): 618-621. According to the American Cancer Society, 3,700 of those deaths occurred in the United States.How Many Women Get Cancer of the Cervix?, American Cancer Society, accessed June 8, 2006 Acting FDA Administrator Dr. Andrew von Eschenbach said the vaccine will have "a dramatic effect" on the health of women around the world. FDA approves cervical cancer vaccine, AP, accessed June 8, 2006

Merck is expected to market Gardasil as a cancer vaccine, rather than an STD vaccine. It remains unclear how widespread the use of the three-shot series will be, in part because of its $360 list price ($120 each for 3 shots). There has also been some opposition to the vaccine by religious conservatives, who fear that it will have the unintended consequence of encouraging unsafe sexual activity. Merck has also suggested that governments make vaccination with Gardasil mandatory for school attendance, which has upset some conservative groups. FDA approves cervical cancer vaccine, AP, accessed June 8, 2006 Moral majority take on GSK and Merck over cancer drugs, accessed June 12, 2006

References

External links

http://www.merck.com
http://www.gardasil.com
http://www.cancer.gov/cancertopics/hpv-vaccines
http://www.nlm.nih.gov/medlineplus//hpv.html
http://www.cdc.gov/std/hpv
http://www.igardasil.com