For Janice Fitzgibbon, this is the story of a miracle drug.

Two years ago, when she came to the Arthritis Clinic of Northern Virginia to receive her first infusion of an experimental treatment for lupus, she had been in a fog of pain and fear for three years.

“Days would go by when I couldn’t get out of bed. When I was better, I was constantly afraid because I didn’t know when the flares would strike again,” said Fitzgibbon. “My world was so narrow. Once I spent eight days on the couch, watching Turner Classic Movies. And no one could really understand what was wrong with me.”

Today, as far as she can tell, she’s a normal 54-year-old woman. “I walk three miles a day. I lift weights.”

The difference, says Fitzgibbon, is belimumab, or Benlysta, which won a Food and Drug Administration license this year as the first drug ever designed specifically to fight the symptoms and causes of lupus.

For Arthur Weinstein, chief of rheumatology at the Washington Hospital Center, Benlysta is a drug that squeaked through the FDA approval process with a great deal of uncertainty about its ultimate value. “I’m happy that the drug is approved, and I hope it will find a place,” he said. “Whether it will remains to be seen.”

Weinstein estimates that 10 to 20 percent of lupus patients might benefit from Benlysta, and he has no idea how much the drug will help that minority in the long run. Meanwhile, the drug is expected to cost about $35,000 for 12 monthly infusions.

In the studies that led to the drug’s approval, the percentage of patients who improved on Benlysta was only slightly higher than that of those who improved on a placebo. As a result, some rheumatologists are leery about the high cost of trying it.

“From the data, it doesn’t look like a great drug,” said John J. Cush, a rheumatologist in Dallas. “I’m not sure who will benefit from it.”

This is the dilemma facing those suffering from lupus. For the first time in 50 years, there is a possible remedy for their fearsome, unpredictable and terribly painful disease. But it might not work for them, and they may never even be offered the drug because of its high price tag.

Difficult to diagnose

Lupus is an autoimmune disease, a disorder in which the immune system, for mostly unknown reasons, turns on the body. It can attack any organ, from skin to bone to kidneys, heart and brain. More than 90 percent of the patients are women.

“It seemed like my symptoms changed constantly: One week it was my joints, then I got ulcers in my mouth, then rashes,” said Fitzgibbon. “It was like, ‘Okay, lupus, where are you going to hit me next?’ ”

According to the Lupus Foundation of America, 1.5 million Americans have lupus or related diseases. However, only about 325,000 people have been given that diagnosis by rheumatologists, who specialize in lupus because the disease almost always attacks a patient’s joints. The vagueness and difficulty of lupus diagnosis — there is no single blood test or symptom that defines the disease — explain the disparity. People with less severe symptoms don’t always see a rheumatologist.

As hard as it is to define lupus, it’s even harder to effectively treat the disease. It’s not unusual for 25-year-old lupus patients to be taking five or six drugs at a time, ranging from steroids to chemotherapy agents to an antimalarial drug, in an effort to control the pain and other symptoms. Loss of fertility, loss of teeth, bone loss and seizures are not uncommon side effects. Often, the drugs makes patients nearly as sick as they would be with lupus alone. There is no cure for lupus, and Benlysta, which went on the market in March, won’t change that.

“The drug is designed for patients who are already on at least two other drugs and still unable to check the effects of their disease,” says Barry A. Labinger, vice president for commercialization at Human Genome Sciences, the Gaithersburg-based company that makes the drug. HGS believes that as many as 200,000 of the 325,000 patients with rheumatologist-diagnosed lupus fall into that category, he said.

Benlysta marks a landmark for the 19-year-old company as well as for lupus patients: it’s the first drug the FDA has approved from HGS, a company that epitomized the optimistic hype of the biotech bubble a decade ago but had seen numerous drug candidates fail to reach the market since then.

Labinger is optimistic that the drug will be an important treatment for lupus. It works by disrupting the response of B cells, which are white blood cells that create antibodies. Benlysta blocks the action of a protein that causes the cells to proliferate when it is linked to receptors on B cells. In effect, Benlysta dims the immune response, particularly the part that causes autoimmune reactions.

Labinger says the price of Benlysta is in line with that of other monoclonal antibodies, a relatively new class of drugs that are expensive to produce. So far, he said, insurers have shown no hesi­ta­tion about paying for the drug.

‘A different woman’

For Penny Fletcher, head of the Washington chapter of the Lupus Foundation of America, Benlysta means hope. “I knew Janice when she was just getting into that clinical trial, and she’s a different woman,” Fletcher said, referring to Fitzgibbon. “It has helped her avoid the flares and allowed her to have a more stable health with less pain and fear.

“For the patients it helps, it’s wonderful,” Fletcher adds, “but it’s a significant drug for all patients with lupus” because it may lead to other lupus medications.

In recent decades, many seemingly effective lupus candidate drugs have failed, but the FDA’s licensure of Benlysta has encouraged other companies to stay in the hunt, says Kenneth Kalunian, who directs the Lupus Clinical Trials Consortium branch at the University of California at San Diego. These companies include Genentech, Medimmune, Astra-Zeneca and Eli Lilly.

Nothing is ever simple with lupus, as the HGS trial showed. Lupus symptoms come and go and vary from patient to patient. Since there are few clear tests of the disease’s progression, HGS devised a coding system to measure the drug’s effect on the severity of the participants’ symptoms.

During an early phase of the trial, African Americans — who, for unknown reasons, are disproportionately affected by the disease — seemed to do particularly well on the drug, but in a larger, later trial, this group got almost no benefit. Statistically, neither of these results was significant, but they were troubling enough for HGS to promise a separate trial involving only African American patients.

Janice Fitzgibbon — very thin, with short blonde hair and sharp features — lives on a comfortable, tree-lined street in McLean. Five years ago, when she was 49, her finger and toe joints began to hurt, and then her elbows and neck and knees. “I was like, ‘Whoa, what is this?’ ” she said. Worse than the pain was the crushing fatigue. “I was always a good sleeper. Now I woke up tired. I felt like a shark: I had to keep moving or I’d fall asleep.”

The first time she had severe pain, which eventually spread through her body, leaving her unable to walk up stairs, Fitzgibbon got an infusion of steroids, which caused sleeplessness and strange, suicidal thoughts. “The disease is insidious and capricious. You can’t make plans; you can’t tell what day the flares will happen,” she said. “It’s hard to get people to understand.”

Still, her case is considered mild. She hasn’t lost her eyesight or suffered seizures or needed a hip replacement. “When I meet women who’ve suffered these things, it makes me feel like a fraud,” she said.

Lupus symptoms creep up on the patient, with rising pain and flagging energy. In Fitzgibbon’s case, feeling better was also a gradual process. “After two or three months of infusions [as part of a Benlysta clinical trial], I said, ‘This isn’t working. I must be on the placebo arm.’ And my husband said, ‘Are you kidding? You don’t look gray anymore. You don’t fall asleep at 6 p.m. on the couch.’ After six months, I knew it was working. I was staying up later, sleeping better. I could take my dog for a walk. Some days I don’t remember I have lupus.”

She has now been on the drug for two years and continues to receive the monthly infusions for free under the clinical trial.

HGS, delighted to have a potentially life-altering drug to sell after years of false starts, seems relatively humble about Benlysta’s potential. Its long-term value remains to be seen, the company acknowledges.

“Rheumatologists are learning as they go, and they’ll have to experiment in their own practices to see how well it works,” said Labinger. “There are no simple outcomes with lupus.”

Allen is a freelance writer in Washington.