Shares of the U.S. drug developer fell as much as 11 percent to
$57.40 in early trading on Monday, but recouped some losses to be
down about 3.7 percent.
The drug, vadastuximab talirine, was being evaluated in the
late-stage study, Cascade, to treat a form of blood cancer called
acute myeloid leukemia (AML).
Seattle Genetics declined to disclose the number of deaths, but said
they were not related to liver toxicity, based on available data.
In December, the U.S. Food and Drug Administration (FDA) had imposed
a clinical hold on several early stage studies testing vadastuximab
talirine after six AML patients were identified with liver toxicity
and four died. The hold was lifted in March.
The discontinuation of Cascade is not related to the clinical hold
from December, the company said in an email.
Seattle Genetics also said it would suspend patient enrollment and
treatment in all trials involving vadastuximab talirine, including
an early-stage study in patients with another form of blood cancer.
The company, which is developing various cancer drugs, said it would
consult the FDA regarding future plans for vadastuximab talirine.
At least three analysts cut their revenue estimates for Seattle
Genetics following the discontinuation of the trial.
Oppenheimer analyst Leah Rush Cann slashed her estimated 2021 total
revenue by 12.5 percent.
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But some analysts turned their focus
to the company's Adcetris drug ahead of a late-stage study readout
expected by the end of the year.
Adcetris is already approved in the United States to treat patients
with classical Hodgkin lymphoma who have not realized enough
benefits from prior therapies.
The drug, which generated about $71 million in North America sales
last year, is also being developed in combination with Bristol-Myers
Squibb's immunotherapy, Opdivo, to treat relapsed hodgkin lymphoma
The trial, involving previously untreated HL patients, could help
expand the Adcetris label.
(Reporting by Akankshita Mukhopadhyay in Bengaluru; Editing by Sai
Sachin Ravikumar and Sriraj Kalluvila)
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