Microbicides, vaccines will cut unintended pregnancies and STDs
Forecast for the family planning field is optimistic
Plan to see a microbicide in the next 20 years that women can use to protect themselves from sexually transmitted diseases (STDs) and unintended pregnancy, and don’t be surprised if there isn’t at least one method available that is aimed at male contraception. Such is the consensus among scientists and family planning experts surveyed by Contraceptive Technology Update for this 20th anniversary issue.
Watch for two waves of microbicidal products, says Polly Harrison, PhD, director of the Alliance for Microbicide Development in Takoma Park, MD, a consortium of companies, scientists, and advocates focused on bringing such products to market. The first line of microbicides most likely will be those that loosely fall under the surfactant/detergent category. The reason? Microbicide research spun off from surfactants such as nonoxynol-9 (N-9), which in lab results is lethal to organisms that cause gonorrhea, genital herpes, trichomoniasis, syphilis, and AIDS. (See analysis of microbicide research in a two-part CTU series: March 1999, p. 25, and April 1999, p. 37.)
"I am working on the premise that the things we have been working on longest will give us some kind of reward, certainly in 20 years," says Harrison. (Learn more about the status of microbicide development at Microbicides 2000, a conference scheduled for March 13-16 in Washington, DC. See resource box, p. 3, for details.)
The Population Council of New York City is initiating two sets of expanded safety studies, one in South Africa and the other in Thailand, to evaluate the safety and acceptability of PC-515. PC-515 is a microbicidal gel containing carrageenan, a sulfated polysaccharide derived from seaweed.
While the two studies will not look at use of the microbicide as a contraceptive, PC-515 is readily compatible with the N-9 spermicide, says Elof Johansson, MD, a Population Council vice president and director of its Center for Biomedical Research. The council recently received a $4 million grant from the Bill and Melinda Gates Foundation of Seattle for product development of such a microbicide for women to use to protect themselves from HIV/AIDS and other STDs.
The Population Council also is scheduling phase III trials for its vaginal contraceptive rings, Johansson reports. The Center for Biomedical Research has spent 20 years developing such ring formulations for female contraceptive use. (See CTU, May 1998, p. 57, for research developments in vaginal contraceptive rings.)
Male systemic contraceptives on the horizon?
Male systemic contraceptives, as well as nonsystemic approaches that will interfere with sperm maturation, may well be seen in the next 20 years, according to Henry Gabelnick, PhD, director of the Contraceptive Research and Development Program in Arlington, VA.
Hormonal approaches include use of such steroids as testosterone enanthate, testosterone buciclate, testosterone undecanoate, and cyproterone acetate, which may be delivered by pill, implant, or injection. Nonsystemic approaches that interrupt the maturation of sperm cells via action on the function of the epididymis also are being examined. (For a more complete overview of male contraceptive research, see CTU, February 1998, p. 22.)
One of the greatest challenges for any new method is that none of them in and of themselves is going to be what pharmaceutical companies consider a "blockbuster drug. With Lipitor cholesterol reducers at $5 million estimates for next year, it is hard to imagine any individual contraceptive product bringing in that kind of volume," notes Gabelnick, referring to atorvastatin calcium, marketed by Parke-Davis of Morris Plains, NJ, and Pfizer of New York City. "The European companies are introducing products, and American companies are going to compete to maintain their market share."
Despite a dramatic need and promising advances in science, no new contraceptives will reach the market soon without stronger support and collaboration among government, industry, private insurance, and the public, reports a 1996 study from the Institutes of Medicine in Bethesda, MD.1
While American women continue to lack access to many methods such as the levonorgestrel intrauterine device for contraception and mifepristone for medical abortion, positive advances have been made in the past 20 years.
Daniel Mishell Jr., MD, professor in the department of obstetrics and gynecology at the Keck School of Medicine at the University of Southern California in Los Angeles, sees the top developments as the introduction of progestin-containing subdermal implants, worldwide use of the CuT380A and levonorgestrel IUDs, and development of mifepristone and other medical means of early pregnancy termination.
Depot medroxyprogesterone acetate (DMPA, Depo-Provera) contraceptive injections; low-dose oral contraceptives; barrier contraceptive options such as the female condom, cervical cap, polyurethane male condom; and dedicated emergency contraceptive pills also are touted as important milestones in expanding choices in reproductive health.
"The major advance over the last 20 years is probably not so much the introduction of groundbreaking new techniques as it is the introduction of variety," reflects Robert Rebar, MD, professor and chairman of the department of obstetrics and gynecology at the University of Cincinnati College of Medicine. "It is clear that the more different forms and types of contraception that are available to individual people, the more likely they are to find some method that is acceptable to them."
Despite the promise of new contraceptive methods, it is the basic ability to discuss and provide education on the subjects surrounding reproductive health that will result in real progress for American men and women, observes Linda Dominguez, RNC, OGNP, assistant medical director of Planned Parent hood of New Mexico in Albuquerque. "We cannot let ourselves believe that the technologies are the answer," says Dominguez, who challenges fellow clinicians to become more skillful in the professional craft of conversation. "We must be able to engage in honest discussions with our patients regarding how the technologies will impact and interface within the context of their individual and very special lives." (Dominguez and other members of CTU’s editorial advisory board share their insights on the important reproductive health advances of the past 20 years, p. 13.)
Reference
1. Harrison PF, Rosenfield A, eds. Contraceptive Research and Development. Washington, DC: Institute of Medicine, National Academy Press; 1996.
Microbicides 2000 is a 2½-day conference sponsored by national and international research and advocacy groups with the Office of AIDS Research of the National Institutes of Health. Scheduled for March 13-16 in Washington, DC, it is for researchers and public health workers from developed and developing countries to expand knowledge about topical microbicides, identify practical applications for current research and clinical trials, and present innovative research. For a detailed brochure containing a second announcement, call for abstracts, and registration information, contact:
• Mary Dannahey, c/o Microbicides 2000, 7101 Wisconsin Ave., Suite 1300, Bethesda, MD 20814. Phone: (301) 986-4870. Fax: (301) 913-0351. E-mail: [email protected].
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