(Adds analyst comments, shares)
June 26 (Reuters) - Seattle Genetics Inc and Japan's Takeda Pharmaceutical Co Ltd said on Monday that their drug met the main goal in a late-stage study of helping blood cancer patients live longer without their condition worsening.
However, Seattle Genetics' shares fell 11 percent as investors were unimpressed by the difference in the progression free survival rate of patients on the combination therapy testing the companies' Adcetris drug and the control arm.
The study testing the combination as an initial treatment for advanced Hodgkin's lymphoma showed 82.1 percent lower risk of cancer progression in patients, compared with 77.2 percent in the control arm.
The control arm used standard-of-care chemotherapy, ABVD, which combines adriamycin, bleomycin, vinblastine and dacarbazine drugs.
The relatively modest improvement of about 5 percent could generate cost concerns among payers, but the benefit from removing bleomycin from the treatment regimen could be substantial, particularly for younger patients, SunTrust Bank analyst Yatin Suneja said.
Doctors for long have been trying to get rid of bleomycin from the chemotherapy regimen to increase the long-term durable response rate and decrease toxicity, Seattle Genetics Chief Executive Clay Siegall told Reuters.
Adcetris is approved in the United States to treat patients with classical Hodgkin's lymphoma, who have already received a stem cell transplant or two chemotherapies. The drug is also approved to treat anaplastic large cell lymphoma in patients who have undergone chemotherapy.
Adcetris, known chemically as brentuximab vedotin, links a tumor-targeting antibody to a cancer-killing chemotherapy drug with the goal of limiting side effects.
Hodgkin's lymphoma is a type of cancer that starts in white blood cells. It typically begins in the lymph nodes in one region of the body and then spreads throughout the lymph system.
According to the American Cancer Society, about 8,260 Americans were diagnosed with Hodgkin's lymphoma so far in 2017, out of which about 1,070 died.
The U.S. drug developer, which partnered with Takeda to co-develop and commercialize Adcetris outside the United States, said it would file for an expanded label in the United States as soon as possible.
The drug, which generated about $266 million in North America sales last year, is also being developed in combination with Bristol-Myers Squibb's immunotherapy, Opdivo, to treat relapsed Hodgkin's lymphoma. (Reporting by Divya Grover in Bengaluru; Editing by Anil D'Silva)