) -- A small clinical study treating elderly Hodgkin lymphoma patients with a combination of

Seattle Genetics'

(SGEN) - Get Report

Adcetris and chemotherapy has been stopped temporarily due to reports of pancreatitis, a dangerous swelling of the pancreas, the company confirmed Tuesday.

The decision to suspend patient enrollment in the Adcetris study due to concerns about pancreatitis was made by researchers at Chicago's Northwestern University, which designed and is conducting the study. Seattle Genetics says none of its Adcetris studies have been halted for any toxicity reasons.

JMP Securities first picked up on the Adcetris study halt Friday following a presentation by Northwestern's Dr. Andrew Evens at a lymphoma research meeting in Lugano, Switzerland. As word filtered back through Wall Street Friday, Seattle Genetics shares sold off moderately. The stock recovered partially by the close of Friday trading after Seattle Genetics denied any knowledge of an Adcetris study being halted due to safety concerns.

Now, the company admits its denial Friday was a mistake.

"We looked into this further, and Dr. Evens apparently made a comment on Friday at the ICML conference in Lugano, Switzerland that he had observed some pancreatitis in an investigator-sponsored trial of Adcetris," said company spokeswoman Tricia Larson, in an email statement. "Currently, enrollment in that investigator-sponsored trial is on temporary hold, with the intention of reopening in the near future. None of our corporate trials of Adcetris have been halted for any toxicity reasons."

The phase II study in question is enrolling

patients 60 years or older with previously untreated Hodgkin lymphoma

. The patients are treated first with Adcetris, followed by a chemotherapy cocktail containing adriamycin, vinblastine and dacarbazine, colloquially known as AVD.

The rate and severity of the pancreatitis observed in the study has not been disclosed. Evens did not respond to an email requesting comment.

Pancreatitis is a "rare, known adverse event in patients treated with Adcetris," said Seattle Genetics' Larson.

Adcetris was approved in 2011 for two different types of lymphoma, including Hodgkin, but only in patients no longer responding to previously approved treatments. Seattle Genetics is conducting numerous follow-on studies to expand use of Adcetris, including studies of previously untreated Hodgkin lymphoma patients.

One of these Seattle Genetics' phase III studies --

dubbed "Echelon-1"

-- uses the same Adcetris plus AVD chemotherapy regimen as the study halted by Northwestern.


company-sponsored phase II study

utilizes Adcetris on its own in previously untreated elderly Hodgkin lymphoma patients.

Seattle Genetics reported first-quarter Adcetris net sales of $34 million and said net sales for the entire year would be in the range of $130 million to $140 million, flat with 2012 net sales.

On Tuesday, Seattle Genetics were up 4.5% to $31.26 in early trading after the company announced a new drug development partnership with Bayer.

-- Reported by Adam Feuerstein in Boston.

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