First Commercial Interferon Use Allowed : Genetically Engineered Molecules Will Combat Rare Leukemia
Calling it the beginning of “a new age in medicine,” Health and Human Services Secretary Otis R. Bowen Wednesday announced federal approval of a genetically engineered type of interferon to treat a rare form of adult leukemia--a development that he predicted will have far-reaching applications in the future treatment of a wide range of cancers and viral diseases.
The substance will be used to combat hairy cell leukemia, a chronic cancer of white blood cells that affects an estimated 2,000 to 3,000 Americans, most of them men in their 50s. Until now, there has been no effective therapy for the cancer, so named because of the hairy appearance of the surface of malignant cells. Patients with the disease usually survive no more than several years, with death usually caused by infection.
Bowen and Food and Drug Administration Commissioner Dr. Frank E. Young, in announcing the first commercial use of interferon in this country, credited “revolutionary new” recombinant DNA technology--or gene splicing--for enabling scientists to produce large amounts of these molecules for the first time.
“The knowledge that will be gained through the rapid introduction of alpha interferon therapy for hairy cell leukemia will likely hasten the day that interferon and other recombinant DNA products can fully manifest their promises as modern medical miracles,” Bowen said at a press conference.
Whether these high hopes are realized, however, remains to be seen.
Cancer Research Grant
Interferon has been touted as a potential cancer drug for nearly 30 years. It gained tremendous publicity only in 1978 when the American Cancer Society gave scientists $2 million for interferon research; it was the largest single grant ever made by the private cancer group. But those and subsequent investigations led to generally disappointing results and excitement about interferon had waned before Wednesday’s announcement.
Young said that the three major types of interferon are now being tested on several diseases, including chronic myelogenous leukemia, a second kind of adult leukemia; Kaposi’s sarcoma, a severe capillary cancer associated with AIDS; and juvenile laryngeal papilloma, a benign tumor of the larynx in children.
“Further clinical testing will be needed to determine how effective interferon will be for any of these indications but I am confident that this new approved treatment for hairy cell leukemia is the forerunner for many other successful and life-saving applications of biotechnology,” Young said.
“This is a milestone, a breakthrough--a sign of what is likely to come,” Young added. “It provides new hope not only to those who suffer from hairy cell leukemia, but to all of us.”
Interferons are a family of small hormone-like protein molecules secreted naturally by human cells to fight viral and other infections. There are three types: leukocyte, or alpha, produced by white blood cells; fibroblast, or beta, produced by connective tissue cells; and immune interferon, or gamma, produced by T-cells, a specific variety of white blood cells that are part of the immune system. The government approval Wednesday applies to alpha interferon.
Discovered in 1957
Interferon was discovered in 1957 by Alick Isaacs and Jean Lindemann, virologists at London’s National Institute for Medical Research.
After their discovery, scientists had hoped that they could prove effective against many illnesses, but studies were disappointing, largely because researchers were dependent on the extremely small amounts produced by the body--the only source of interferon known to them at the time.
“Only in the last decade with the development of gene splicing have scientists been able to produce the amounts of this substance needed to conduct clinical (human) trials to discover its real potential in treating human disease,” Young said.
The recombinant DNA technology takes genes that contain the “production code” for interferon and combines them with harmless bacteria. The bacteria then become “factories” capable of manufacturing large amounts of interferon identical to that produced by the human body.
Hairy cell leukemia is believed to be caused by human T-cell lymphotropic virus I (HTLV-I), from the same family of human retroviruses responsible for AIDS. Conventional chemotherapy is of limited value in treating hairy cell leukemia, FDA officials said. Removal of the spleen, supportive chemotherapy and repeated blood and platelet transfusions have been the traditional treatments, but the mortality rate is about 7% to 20% a year, they said.
Remission Achieved
Bowen said that alpha interferon has been found to be “remarkably effective” in treating hairy cell leukemia. Studies using alpha interferon on more than 2,000 patients produced partial or complete remission in 75% to 90% of patients, the department said.
Overall, survival rates of more than two years--regardless of remission--were seen in 92% to 94% of the patients. The department said it was continuing to monitor these patients for long-term survival rates.
The government approval was given to two brands of alpha interferon produced by Hoffman-La Roche Inc., of Nutley, N.J., and Shering Corp. of Kenilworth, N.J. The FDA said that the two brands were developed independently by the companies but produced by the same recombinant DNA technology.
A spokesman for Hoffman-La Roche said the substance, administered through an injection under the skin, is expected to cost about $35 per dose, or an estimated $3,000 to $5,000 a year. “But many hospital days and surgical procedures will be prevented,” Young said.
