Scientists hope Velcade, or similar drugs, could one day become effective for other cancers.
The drug is the first anticancer proteasome inhibitor, meaning it targets an enzyme key to cell growth. Uncontrolled cell growth is cancer's hallmark. The idea: Inhibit proteasome action, and chemicals that control cell growth should be disrupted enough for cancer cells to die.
Velcade maker Millennium Pharmaceuticals first tried the approach to treat multiple myeloma, a usually fatal blood cancer that strikes 14,600 Americans a year. The condition is treatable but incurable, and patients eventually run out of options. Half die within five years of diagnosis.
Velcade isn't a cure either, but studies suggest it can help a fraction of patients who have exhausted other alternatives, the Food and Drug Administration ruled late Tuesday.
The FDA approved Velcade's sale less than four months after Millennium filed its application, under a special program that lets promising drugs for life-threatening illnesses sell before there's final proof of how well they work.
Millennium gave Velcade injections to 188 patients who had relapsed despite about six prior therapies. Some 28 percent improved, and that improvement lasted a median of one year — a surprising length of time for people so sick, the FDA said.
The FDA is requiring Cambridge, Mass.-based Millennium to do further research to prove if that response actually translates into living longer.
But it's a response not seen with standard chemotherapy for this cancer, "so this was impressive," said Dr. Ann Farrell, who led FDA's review.
Evidence so far suggests "this represents a true advance over existing therapies," added FDA oncology chief Dr. Richard Pazdur.
Normal cells contain proteasome, too, making them vulnerable to the drug. Side effects include many typical of chemotherapy: nausea, fatigue, diarrhea, constipation, headache, decreased appetite, decreased blood cell production, and a nerve damage called peripheral neuropathy.
Still, for some unknown reason, Velcade, known chemically as bortezomib, appeared more likely to select myeloma cells, Farrell said.
Millennium plans to begin shipping Velcade by month's end. It will cost about $20,000 per average course of treatment — 16 to 17 weeks — which is comparable to other injected cancer therapies, according to Barry Greene, the company's general manager in charge of oncology.
Millennium is studying whether Velcade also could treat advanced colon and lung cancer.