Monday, August 10, 1998
Lupus is an enigma, a debilitating autoimmune disorder that primarily strikes women and displays an unpredictable pattern of flares and remissions. With multiple contributing factors and multiple organ involvement, each case differs from the next.
Treatments vary with the organs involved but depend heavily on prednisone, a corticosteroid that produces serious side effects with long term use, making therapy often little better than the disorder.
But even if the disease is still poorly understood, companies are beginning to make progress in developing treatments, and practitioners say that new drugs for lupus will be enthusiastically welcomed.
No one knows exactly how many lupus patients there are in the U.S., but whatever the numbers, they are almost certainly larger than those of many better known diseases. The Lupus Foundation of America estimates the lupus population at 1.2-2.4 million . greater than the combined populations of multiple sclerosis, cystic fibrosis, sickle cell anemia and leukemia.
Others put the numbers lower. David Wallis, clinical professor of medicine at UCLA, said the NIH estimates there are 180,000 patients in the U.S., but admits the figure is low. Because the official government figure is under 200,000, however, Wallis pointed out that lupus treatments qualify for orphan drug status, and products developed for lupus can be considered for the FDA. s fast track approval process.
Companies have another incentive to pursue lupus: many rheumatologists believe that effective therapies for lupus will work across other autoimmune indications.
Robert Lahita, chief of rheumatology and connective tissue diseases at St. Lukes Roosevelt Hospital and an associate professor at Columbia University (New York, N.Y.), described the study of lupus as having "great appeal. It is the prototypical autoimmune disease, and we can learn more about the autoimmune response through studying it. This is potentially a very fruitful area because the autoimmune response affects so many disorders," he said.
Systemic lupus erythematosus (SLE) has two manifestations. The more serious condition . the "flare," or bout of acute disease . is actually organ-threatening. Although treatment with steroids and other drugs has extended patients. life spans, neither manifestation allows a good quality of life, Wallis said.
Michelle Petri, associate professor of medicine and director of the lupus center at Johns Hopkins University Medical Center (Baltimore, Md.), said rheumatologists need "better control over the disease and to get away from dependence on prednisone, which is so damaging. We. re forced to use it now, and patients hate it," she said.
Side effects of long-term prednisone use include development of high blood pressure, diabetes and osteoporosis as well effects on mood and depression, according to Petri.
Although the causes of lupus remain unknown, the hallmark of the disease is an array of anti-self antibodies that form immune complexes with body tissues, eliciting inflammatory processes that result in organ damage (see pathway chart, above). Patients may develop rashes, joint pain and kidney failure and also can develop heart, lung and central nervous system complications.