Biotech: Similarities Exist Between Drug Firms’ Anti-Cancer Hopefuls
The president of Idec Pharmaceuticals Corp. in San Diego said the company is on track to take its experimental cancer drug Zevalin to the Food and Drug Administration in mid-2000.
Idec’s rival, South San Francisco-based Coulter Pharmaceutical Inc. however, is still ahead with a similarly unique treatment, some experts agree.
Both Idec and Coulter have developed a unique treatment for non-Hodgkin’s lymphoma, which some industry experts believe could potentially replace conventional methods of chemotherapy and radiation.
The two treatments are unique, combining an antibody with a radioactive particle to kill a tumor, but leave the healthy cells intact.
Coulter submitted its clinical data in August to the FDA for approval. But the company suffered a setback when the FDA asked it to modify its application, giving Idec an opportunity to close the gap.
Idec presented positive interim results of four clinical trials at the annual meeting of the American Society for Hematology in New Orleans on Dec. 6.
Analysts have long expressed high expectations for Zevalin, which is a unique treatment combining a radioactive form of metal, yttrium, with a cancer-fighting antibody.
The approach of using antibodies, which occur naturally in the bloodstream, to deliver a radioactive particle to a tumor and kill it without harming the healthy cells, has long proven elusive and would be a first on the market.
“Six months ago we were one year behind, today we are three months behind,” said Bill Rastetter, Idec’s president, chairman and CEO.
But Coulter’s release of encouraging results of its experimental drug Bexxar at the annual hematology meeting is likely to keep the company ahead of Idec, according to James McCamant, editor of the Berkeley-based Medical Technology Stock Letter.
But Idec’s previous dealings with the FDA may give it an edge on the competition because they are less likely to make mistakes, he added.
Idec was the first company to have a cancer-fighting antibody on the market. The drug, Rituxan, which does not have a radioactive isotope attached, is fast-becoming a standard treatment for patients with certain lymphomas
Coulter doesn’t have a drug on the market and has yet to re-file for Bexxar’s approval.
A Coulter official declined to give out information, referring inquiries to 2000.
Data presented by Coulter and its British partner SmithKline Beecham PLC at the hematology meeting showed encouraging results for Bexxar.
Out of 179 patients with low-grade non-Hodgkin’s lymphoma treated in five early- to late-stage trials, 81 percent responded to Bexxar. Only half the patients responded to their last chemotherapy.
About 39 percent of patients went into complete remission following treatment with Bexxar. That compares to 14 percent of patients who had a complete response, meaning their tumors shrank to undetectable levels following their last chemotherapy.
In Idec’s study comprising 90 patients, about 80 percent of the patients treated with Zevalin showed improvement, compared to 44 percent treated with Rituxan alone, according to a presentation at the hematology meeting.
About 21 percent of patients treated with Zevalin saw a complete response and 59 percent saw a partial response, Idec reported.
“Coulter is still ahead,” said McCamant.
But, he added, while it appears as if both treatments are reasonably close in effectiveness, Idec’s drug is easier to formulate and deliver.
Patients treated with Zevalin receive one infusion of Rituxan the first day, and two infusions, one with Rituxan and one with Zevalin, on the eighth day. Coulter’s drug in turn requires patients to be isolated and in some cases to be hospitalized.
However, analysts say it’s hard to compare the two drugs because the companies’ findings looked at different patients, used different definitions and criteria, according to Bloomberg News. Rastetter agreed, saying, “There will be elements of the two drugs that are quite different.”
He said he asked Coulter to compare the two drugs, but said that’s unlikely to happen.
McCamant said oncologists generally are reluctant to use radioactive isotopes, because they are “much more complicated to administer.” Both Zevalin and Bexxar are aimed at advanced cancers in which patients are in the late, desperate stages of the disease.
Idec officials agree Zevalin will not replace Rituxan, which was approved by the FDA in 1997 for the treatment of patients with non-Hodgkin’s lymphoma who have relapsed or whose tumors do not respond to conventional methods.
Patients receive between six and seven treatments during their life cycle, said Idec spokesman Vince Reardon. Rituxan is administered after patients suffered relapses.
Zevalin would be their “salvage therapy,” or the last resort after all other treatments failed, he said.
About 250,000 Americans suffer from non-Hodgkin’s lymphoma. It is the sixth-leading cause of cancer death in the United States.
