OctoPlus Announces Promising Results for Locteron Phase IIa Clinical Study

OctoPlus N.V. ("OctoPlus" or the "Company") (Euronext: OCTO), the drug delivery and development company, announces today positive initial results of the ongoing SELECT-1 Phase IIa study with its lead product Locteron(TM) , a controlled release interferon alfa for the treatment of chronic hepatitis C (HCV). In the 12-week Phase IIa study, the combination of the highest dose of Locteron evaluated until now, and the antiviral drug ribavirin, achieved an early virologic response (EVR) in 100% of the hepatitis C patients treated. The study reported an overall strong antiviral response at twelve weeks and an adverse event profile that shows substantial tolerability improvement compared to other interferons, either on the market or in development. OctoPlus is co-developing Locteron with its partner Biolex Therapeutics.

These initial results are from the first three cohorts (160, 320 and 480 ug); treatment of the fourth and last cohort (640ug) is ongoing. Complete and final study results will be reported in the fourth quarter of this year.

Professor Peter Jansen, head of the AMC Liver Center at the department of Gastroenterology and Hepatology of the Academic Medical Center in Amsterdam, the Netherlands, comments:

"These results are very encouraging: Locteron's adverse event profile shows potential to significantly improve hepatitis C therapy. The results pave the way for the commencement of the Phase IIb study, in which I am excited to be involved."

Design of the Phase IIa study

The SELECT-1 (Safety and Efficacy of Locteron: European Clinical Trial 1) Phase IIa study is a European multi-center, randomized, open-label trial designed to evaluate Locteron in combination with the anti-viral drug ribavirin in previously untreated chronic hepatitis C patients. A total of 32 patients in 4 dose cohorts have been enrolled in the study. The study assesses safety and tolerability and explores viral response of a 12-week treatment with Locteron, administered once every two weeks in subcutaneous doses of 160, 320, 480 and 640 ug, and combined with oral ribavirin treatment. Dosing of the first three eight-patient cohorts commenced in January 2007. Based on a favorable safety review of the results from the first three cohorts, dosing of patients in the 640 ug cohort commenced in May 2007.

Antiviral response in doses 160, 320 and 480 ug

At the conclusion of the study, 12 weeks of treatment, the results for the 160, 320 and 480 ug cohorts were as follows:

--  A dose response was observed in the study, with patients treated with
    the 320 and 480 ug doses of Locteron demonstrating a greater reduction in
    hepatitis C virus than the patients treated with the 160 ug dose at all
    measurement times.  Average viral reduction after 12 weeks of treatment for
    the 320 and 480 ug doses was 4.5 and 4.2 logs, respectively, compared to
    1.8 logs in the lowest dose of 160 ug.
--  After 12 weeks of treatment, 63% (5/8) of the patients had
    undetectable levels of hepatitis C virus, measured by plasma RNA < 28
    IU/ml, in both the 320 and 480 ug dose cohorts, compared to 13% (1/8) of
    the patients in the lowest-dose group of 160 ug.
--  The percentage of patients who achieved early virologic response
    (EVR), defined as at least a two-log reduction in hepatitis C virus after
    12 weeks of treatment, was 88% (7/8) and 100% (8/8) in the 320 and 480 ug
    dose Locteron cohorts, respectively, compared to 38% (3/8) of the patients
    in the lowest-dose group of 160 ug.  Achievement of EVR has been broadly
    established to be a pre-requisite for long-term response.
    

Safety and tolerability in doses 160, 320 and 480 ug

The following Locteron side effect and patient tolerability results were observed during the 12 weeks of treatment for the 160, 320 and 480 µg cohorts:

--  Locteron was safe and well tolerated.
--  There were no serious adverse events.
--  The vast majority (over 90%) of the adverse events that were
    experienced were rated as mild.
--  Dose reductions were limited to one patient each in the 320 and 480 ug
    cohorts with none in the 160 ug cohort.
--  No patients discontinued treatment.
    

Side effects were confined to the regular flu-like symptoms and other side effects that are associated with interferon treatment. All adverse events, including flu-like symptoms, were less frequent and less severe than the side effects reported for other interferons. For example, only one patient in the SELECT-1 study receiving Locteron experienced an adverse event rated as severe, a substantial improvement over reported results for Pegasys® and Albuferon(TM) as illustrated below.

< Click on the link at the bottom of the press release for the full press release including graphs. >

Another objective point of comparison for evaluating the tolerability of Locteron and other interferon products across clinical studies is fever, a marker for the family of adverse events characterized as flu-like symptoms. Fever occurred in only one (4%) of the Locteron patients in SELECT-1, notably lower than other interferon products, as illustrated below.