A pivotal trial of Seattle Genetics' experimental cancer-targeting antibody for patients with Hodgkin's lymphoma found that more than a third of them achieved complete remission of their cancer.
The company also said it now expects to submit the drug, brentuximab vedotin, to U.S. regulators in the first quarter of next year for patients with either Hodgkin's lymphoma or anaplastic large cell lymphoma (ALCL) who have stopped responding to other therapies. The company had previously said a submission would occur in the first half of 2011.
"Our goal would be to submit in the first quarter, have an accelerated review and be on the market in 2011," Seattle Genetics' Chief Executive Clay Siegall told Reuters in a telephone interview.
The trial did not compare brentuximab vedotin with another drug, but the complete remission rate for similar patients tends to be in the single digits, he said.
The company is developing the lymphoma drug with Japan's Takeda Pharmaceutical Co, which is discussing with European regulators a possible first-half 2011 submission.
Seattle Genetics had said in September that 75 percent of the trial's 102 patients had remissions or tumor shrinkage of at least 50 percent. The trial involved patients who had stopped responding to standard treatments for the lymphatic cancer.
The full results — presented on Sunday at the annual meeting of the American Society of Hematology in Orlando, Florida — included some sort of tumor reduction in 94 percent of patients.
Brentuximab vedotin links a tumor-targeting antibody to a cancer-killing chemotherapy drug with the goal of limiting side effects. It is designed to home in on an antigen expressed in Hodgkin's lymphoma, several types of T-cell lymphoma and other hematologic malignancies.
Patients in the trial responded to the drug for a median of 29 weeks, according to an independent review. Among patients achieving remission, the median duration of response had not yet been reached at a median follow-up of around one year.
Seattle Genetics said serious side effects seen in the trial included neutropenia, or low levels of white blood cells, (20 percent of patients), peripheral sensory neuropathy (8 percent), low platelet count (8 percent) and anemia (6 percent).
Siegall estimated that there are close to 8,000 patients in the United States with relapsed or refractory Hodgkin's lymphoma and ALCL.
Full results from a mid-stage trial of brentuximab vedotin in ALCL patients are scheduled for presentation at the hematology conference on Tuesday. Top-line results, reported by Seattle Genetics in October, showed that 86 percent of trial patients responded to the antibody drug.
The company is also studying the drug as an initial treatment for Hodgkin's lymphoma and as a maintenance therapy.
Leerink Swann has estimated 2015 sales of brentuximab vedotin at around $302 million.
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