* 73 pct early virological response with Anadys's ANA598
* No serious adverse events seen in ANA598 patients
* CEO sees partnership talks heating up
* Shares fall 15 percent
(Adds analyst comment, share move)
By Bill Berkrot
NEW YORK, Feb 24 An experimental hepatitis C
treatment being developed by Anadys Pharmaceuticals Inc
ANDS.O demonstrated impressive early response rates with no
serious safety issues, according to preliminary data from a
small mid-stage clinical trial.
After 12 weeks of dosing, 73 percent of previously
untreated patients who received 200 milligrams of Anadys's
ANA598 twice daily in combination with standard treatments
achieved undetectable levels of the virus. The 12-week results
are known as a complete early virological response (cEVR).
Anadys shares fell 15 percent after the data were released
as investors may have been disappointed by the unexpected
similarity of response rates at 12 weeks between the Anadys
drug arm and control group of the study.
Of the 14 patients who received the standard treatment of
pegylated interferon and ribavirin, the cEVR rate was a much
higher-than-expected 71 percent.
"It doesn't look like a differentiated product on top of
standard of care. There was essentially no difference between
598 on top of standard of care and standard of care," said
Thinkequity analyst Brian Skorney, calling the control group
response "bizarre" and "confounding."
There was a much larger separation of response rates
between the two treatment arms at weeks 4, 6, 8 and 10, when
the ANA598 viral response was already at 73 percent, while the
standard of care group response was 54 percent.
Anadys said the virtually identical 12-week response rate
between the two arms of its Phase II trial may be due to the
small number of patients, and were likely skewed by one patient
from each group who was unavailable for measurement at week 12
of the study so were not included in the data.
"I can buy the explanation, but I have to see more data to
accept the explanation," Skorney said.
"If we see a repeat in the next data slice, then it's not
compelling," he added.
"We would expect the placebo group number to regress back
to more typical historical norms as the numbers of patients
became larger both in this trial and in subsequent trials,"
Anadys Chief Executive Steve Worland said in a telephone
Analysts on a conference call with the company appeared to
be generally impressed with the ANA598 data.
No one in the 26-patient ANA598 arm of the trial
experienced viral rebound, or a return of the virus once it
appeared to have been knocked out.
No serious adverse events were reported with ANA598, and
the side effects that were observed, such as a rash, were
comparable between the ANA598 patients and those that received
the standard treatment plus a placebo, the company said.
"We're very encouraged. The cEVR number, good safety and
lack of rebound are all very positive for 598," Worland said,
noting that the response rate was "comparable to the most
advanced protease inhibitors in development."
ANA598 belongs to a class of drugs called non-nucleoside
"There's a fair amount of skepticism that a non-nucleoside
that even got a good number early could sustain that number
between week 4 and week 12," Worland said.
"Everybody who experienced benefit from 598, all of that
benefit is preserved through week 12," Worland said. "That's
contrary to expectations and very positive for combining 558
with direct antivirals."
Patients will continue to be treated through 24 or 48
weeks, with the most important data, the sustained virologic
response, or SVR rates, becoming available toward the end of
the year, the company said.
SVR is considered tantamount to a cure for the serious
liver disease. The cure rate for the current treatments is
typically only between 45 percent and 60 percent.
The current standard treatments require 48 weeks of dosing
and are difficult to tolerate with flu-like symptoms often
persisting throughout. Patients not helped by those drugs often
have no alternative but an eventual liver transplant.
Several companies, including Vertex Pharmaceuticals
Inc(VRTX.O) and Merck & Co (MRK.N), are developing promising
new antiviral medicines that have shown far higher cure rates,
often with shorter treatment durations, when combined with
The early response rate for ANA598 is comparable to what
has been seen for those other promising hepatitis C treatments
in clinical trials, while the control group response was far
higher than what has been seen in those other studies.
Discussions on a partnership deal for ANA598 are now
expected to heat up.
"We're resuming an engaged level of dialogue with companies
now that were waiting to see the 12-week data," Worland said.
Anadys shares fell to $1.95 in extended trading from their
Nasdaq close at $2.31.
(Reporting by Bill Berkrot)