said Monday that its experimental cancer drug Velcade proved effective in treating patients with very advanced multiple myeloma, a cancer of the bone marrow.
The Cambridge, Mass.-based biotech firm reported on final results from a phase II study of Velcade at the annual meeting of the American Society of Hematology. Last week, Millennium said it intends to seek marketing
approval for Velcade from the Food and Drug Administration on the basis of results from this study.
Monday's report on Velcade's positive efficacy was largely expected since the company reported preliminary
results from this same study last spring at the American Society of Clinical Oncology meeting.
Millennium shares were off 11% to $9.98 in recent trading, mainly because the data held no real surprises, and many investors sold on the news. Some safety concerns with Velcade that were highlighted during Monday's presentation, although not new, also were likely weighing on the stock.
Data from 193 of 202 patients in the study demonstrated complete remissions in 4% of patients, according to a stringent clinical measurement known as the Blade criteria (pronounced BLAH-day). Another 6% of patients were able to achieve nearly complete remissions, according to Millennium.
The overall response rate in the study was 35%, defined as the total of complete, partial and minor responses, the company said, adding that an independent committee of doctors verified all the patient responses.
The patients enrolled in this study had advanced cases of multiple myeloma that were progressing after receiving an average of six prior treatment regimens. Their average life expectancy was six to nine months, on the basis of historical medical data. Patients in the Velcade study survived an average of 16.4 months.
"These outcomes indicate an important potential advance in the treatment of multiple myeloma, and may offer new hope for increased survival in this patient population," said Dr. Paul Richardson of the Dana-Farber Cancer Institute in Boston, the study's principal investigator, in a statement.
At last spring's ASCO meeting, there were some concerns raised about Velcade patients who experienced pain and numbness in their limbs, a side effect known as peripheral neuropathy. The same safety concern was raised again during Monday's presentation, according to several fund managers in attendance. In its press release, Millennium said that 21% of patients in the study dropped out because of adverse events.
Velcade is a novel cancer-fighting drug, known as a proteasome inhibitor. Proteasomes are enzymes in cells responsible for breaking down a variety of proteins, including many that regulate cell division. If proteasomes do not function properly, they can halt cell division, ultimately causing cells to die.
The theory behind Velcade is that it works by inhibiting the function of the proteasome, thereby stopping cancer cells from dividing, causing them to die. Proteasomes are present in every cell in the body, but researchers believe cancer cells are particularly sensitive to the effects of proteasome inhibition, while healthy cells appear able to recover from the effects.
Banc of America biotech analyst Mike King sponsored a dinner with oncologists over the weekend (before the release of the Velcade data). In a note published Monday morning, King says the doctors all viewed Velcade as a new and promising treatment for multiple myeloma. One doctor, in particular, said that if and when Velcade is approved, he'd likely use it with all his multiple myeloma patients. King does not cover Millennium.