FREMONT, Calif., Aug. 9 /PRNewswire-FirstCall/ -- Protein Design Labs,
Inc. (PDL) (Nasdaq: PDLI) today reported that enrollment will resume in the
optional retreatment arm of its Phase I/II clinical trial of Nuvion(R)
antibody product (visilizumab) in patients with severe ulcerative colitis that
is refractory to treatment with intravenous steroids.
Steven Benner, M.D., Senior Vice President and Chief Medical Officer, PDL,
said, "As expected, an independent Data Safety Monitoring Board (DSMB) has
completed its review of two cases in the retreatment phase that met the
protocol definition of a dose-limiting toxicity, and has concluded that the
retreatment phase of the protocol may safely continue. Patients eligible for
retreatment may once again be enrolled in this part of the study.
"As we noted last week in our conference call, the DSMB review did not
affect enrollment in the dose-ranging Phase I portion of the trial, nor has it
has altered our projected timeline for the development or potential
competitive positioning of visilizumab," Dr. Benner added. "We remain on
track with our strategy that focuses on the most rapid time to approval and we
also certainly plan related additional studies to support broader use once we
have achieved approval to market this drug."
PDL is conducting an ongoing, open-label Phase I/II trial of visilizumab
in the severe ulcerative colitis setting, with three treatment components to
the trial. The primary goal of the study is to establish the optimal dose of
visilizumab for use in future registrational trials. This will be
accomplished through the Phase I dose-ranging component of the trial. When
the Phase I portion of the trial is completed, an additional 20 patients will
be enrolled in the Phase II portion of the study, to provide additional
experience with visilizumab at the optimal dose level. These patients will
receive their initial treatment with visilizumab at the optimal dose level.
The third exploratory component of this ongoing study is the option for
retreatment. Patients previously treated with visilizumab in a completed
Phase I trial or in the ongoing study, who achieved a response and later
relapsed within one year, could receive one additional course of visilizumab.
To date, four patients have received a second course of visilizumab in the
optional retreatment phase. All four of these patients had been participants
in the completed Phase I trial. PDL reported on August 3 that among these
patients, two met the protocol-defined criteria for a Dose-Limiting Toxicity
(DLT). One DLT was the slow recovery of the CD3+CD4+ T-cell count at day 60.
The second patient reported as having a DLT had an asymptomatic elevation of
EBV. This patient had been treated with 6-mercaptopurine prior to visilizumab
and had a CD3+CD4+ T-cell count of 49 cells/microliter prior to visilizumab
retreatment. The DLT was a delay in decline following the expected rise in
EBV levels, in this case to 15,310 copies/ml on day 60. EBV levels
subsequently declined to 1,409 copies/ml by day 70 and were undetectable at
day 87. Per the study protocol, these cases were forwarded to an independent
Data and Safety Monitoring Board (DSMB).
Accrual continues into all dose levels in the dose-ranging Phase I portion
of the clinical trial. The trial is designed to explore four dose levels from
5 micrograms/kg to 12.5 micrograms/kg given I.V. on days 1 and 2 as a bolus
injection. Currently, 50 patients have been treated in this study. Patients
with undetectable Epstein-Barr Virus (EBV) levels are randomized into
treatment in one of the four dose levels. Patients with detectable EBV, but
counts less than 5,000 copies/ml have been enrolled in successive cohorts,
beginning with the lowest dose level. Patients with detectable EBV are being
enrolled in the 10 micrograms/kg dose level. When patients in this cohort
have been followed for 30 days, enrollment of patients with detectable EBV
should begin at the 12.5 micrograms/kg dose level.
An abstract of this study has been accepted for presentation during the
12th United European Gastroenterology Week (UEGW) meeting in Prague, Czech
Republic, on September 29, 2004. The presentation will describe the safety
and activity of visilizumab observed in the Phase I portion of the trial.
The foregoing contains forward-looking statements involving risks and
uncertainties and PDL's actual results may differ materially from those,
express or implied, in the forward-looking statements. In particular, there
can be no assurance that the Phase I/II study will be enrolled on the schedule
currently contemplated, that the study will result in data supportive of
further development or regulatory approval or that additional studies will be
permitted or conducted. Other factors that may cause our actual results to
differ materially from those, express or implied, in the forward-looking
statements in this press release are discussed in our Annual Report on Form
10-K for the year ended December 31, 2003, in our quarterly report on Form
10-Q for the period ended March 31, 2004, and in other filings with the
Securities and Exchange Commission.
Protein Design Labs is a leader in the development of humanized antibodies
to prevent or treat various disease conditions. PDL currently has antibodies
under development for autoimmune and inflammatory conditions, asthma and
cancer. PDL holds fundamental patents for its antibody humanization
technology. Further information on PDL is available at http://www.pdl.com.
NOTE: Protein Design Labs, Humanizing Science and Nuvion are registered
U.S. trademarks and the PDL logo is considered a trademark of Protein Design
Labs, Inc.
SOURCE Protein Design Labs, Inc.
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Related links:
http://www.pdl.com
CONTACT:
James R. Goff, Senior Director, Corporate
Communications of Protein Design Labs, Inc., +1-510-574-1421, or
jgoff@pdl.com
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