Experiment Called ‘Very Encouraging’ : Spray Credited With Preventing Colds
In a major advance against the common cold, scientists reported today that an experimental anti-viral nasal spray, if used daily for a week, can often prevent the spread of colds among household members.
In clinical trials involving more than 150 families, the powerful drug, called alpha-2-interferon, was highly effective against the most common group of viruses that cause these infections, according to researchers at the University of Virginia Medical Center and the University of Adelaide in Australia. They published their studies separately in the new issue of the New England Journal of Medicine.
“This is the first cold therapy that is specifically effective against the causative virus, not just cold symptoms,” said Dr. Jack M. Gwaltney Jr., who worked with Dr. Frederick G. Hayden on the Virginia study. “It is very encouraging.”
Schering-Plough Inc. of Madison, N.J., which manufactures the drug and sponsored the studies, has asked the U.S. Food and Drug Administration to approve the nasal spray for sale by prescription. It is not known when such approval might occur. The review process could take several years.
Compared to the placebo, the spray was effective about 80% of the time against the common group of viruses and about 40% of all colds, according to the studies. The frequency and severity of side effects, such as nose bleeds, were small.
“The remarkable thing . . . (is the) near duplication of data in two completely independent trials conducted on two continents,” Dr. R. Gordon Douglas Jr. of New York Hospital said in a companion editorial commenting on the studies. “Thus, we can be confident of the data.”
Gwaltney cautioned that the nasal spray is still considered experimental. Interferon was not shown, for example, to prevent the spread of colds caused by other groups of viruses or by the flu.
The spray also has not been shown to prevent nasal, throat or cough symptoms once a cold has started, according Dr. Thomas Merigan, an infectious disease specialist at the Stanford University Medical Center.
The side effects of the medicine in children--a primary reservoir of cold viruses--also remain to be established, according to Gwaltney.
In the Australian study, involving 97 families, only adults were treated. In the U.S. study, involving 60 families, those under 12 were excluded from treatment.
The interferon spray was effective against the most common virus group, called rhinoviruses, which account for 30% to 50% of all colds in adults.
Previous studies have shown that the interferon spray is effective in preventing rhinovirus colds. But frequent and severe side effects, such as nasal irritation and bleeding, outweighed the drug’s benefits. Therefore, researchers changed strategies.
Instead of trying to prevent colds by daily use of the spray throughout the cold season, they sought to prevent the spread of colds in “high-risk” situations, such as within a household after one member becomes ill.
Spread by Contact
Colds are caused by more than 200 viruses and typically are transmitted by close contact, such as touching the hands of an infected person, as opposed to being spread through the air.
In the new studies, researchers were able to reduce the frequency of side effects by using a higher dose of medication, administered once daily, by shortening the course of therapy to one week and by mandating a two-week recovery period before further use of the spray.
In both studies, families including at least two adults and two children were randomly given either the medicine or a placebo. Neither participants nor researchers knew who was in which group.
Healthy household members began using the spray if another developed a cold; the ill person was not treated. Therapy was monitored through home visits, telephone interviews, blood tests and cultures of viruses.
In the Virginia study, 1.3% of interferon sprayers developed laboratory-proven rhinovirus colds, compared to 15.1% of the placebo sprayers.
In all, those who used the interferon spray had 32% fewer days with runny nose, 35% fewer days with sore throat, 43% fewer days with nasal blockage and 54% fewer days with cough, compared to people in the placebo group.
Incidence of Bleeding
Nasal bleeding in the U.S. study was observed in 13.6% of the interferon users and 7.7% of the placebo users. Repeated interferon treatments did not cause an increased risk of side effects.
Interferons are proteins that are present in small amounts in human cells and play an important role in the body’s immune defense system. They have been tested since the early 1970s as drugs against a variety of viruses and cancers. In recent years, they have been manufactured in large quantities through recombinant DNA technology, thus allowing for extensive clinical tests.
Schering-Plough is also seeking FDA approval to market the drug for treatment of venereal warts and some human cancers, including melanoma, hairy cell leukemia and Kaposi’s sarcoma, which is common in patients with the deadly acquired immune deficiency syndrome. A company spokesman said FDA approval of interferon for at least one of these indications is a “good prospect” for 1986.
An interferon nasal spray would be sold as a powder, which could be stored in a pharmacy or in a medicine cabinet for up to two years, according to the company. The powder would be activated by mixing it with a liquid stored in another part of the sprayer. The liquid medicine would be active for one week if kept at room temperature or for four weeks if refrigerated.
Vast U.S. Market
A company spokesman said the spray, if approved, would be priced to be “economically viable.” The potential United States market is vast, because 1985 sales for non-prescription cold medicines alone were estimated in the New England Journal editorial to be greater than $550 million.
News of the successful interferon trials comes on the heels of a September announcement by scientists at Purdue University and the University of Wisconsin that they created a detailed three-dimensional model of a cold virus, the first such image of any virus that infects animals and humans. The model, they said, will help them develop other strategies to fight cold viruses.
