OctoPlus’ Licensee Biolex Therapeutics Commences Phase IIb study with Locteron

LEIDEN, THE NETHERLANDS--(Marketwire - April 20, 2009) - OctoPlus N.V. (“OctoPlus” or “the Company”) (EURONEXT: OCTO) announces today that its licensee Biolex Therapeutics (see separate Biolex press release on www.biolex.com) has commenced patient dosing in the SELECT-2 Phase IIb clinical study of Locteron®, a controlled release formulation of interferon alpha for the treatment of chronic hepatitis C. Locteron combines OctoPlus’ controlled release drug delivery technology PolyActive® with Biolex’ interferon alpha and is the most advanced product in clinical development incorporating one of OctoPlus’ proprietary drug delivery technologies.

In October 2008 OctoPlus entered into an exclusive license and product acquisition agreement with Biolex, worth up to EUR 100 million. As a result, Biolex holds the full commercial rights to Locteron and is responsible for development and commercialisation, and OctoPlus is paid by Biolex to perform process development and to manufacture Locteron.

The Phase IIb study is being conducted in the United States and Europe in 100 treatment-naïve, genotype-1, chronic hepatitis C patients. Patients will be randomised into one of four dosing cohorts, the 320, 480 or 640 µg dose of Locteron (administered once every two weeks) or a control arm consisting of PEG-Intron® (administered every week), with all patients receiving weight-based ribavirin. Patients will be treated for 48 weeks and will be followed for an additional 24 weeks to determine the sustained virologic response (SVR) rate. The interim results after 12 weeks of treatment are expected to be used as the basis for the selection of the Locteron dose(s) for Phase III studies.

Simon Sturge, CEO of OctoPlus comments: “Having announced earlier this month the seventh company to sign an evaluation contract for OctoPlus’ technology, we are now delighted to report this progress in Locteron’s clinical development. The start of Biolex’s Phase IIb study of Locteron is a major milestone in the commercialisation of our proprietary PolyActive technology. We look forward to the results of this large-scale study in hepatitis C patients, which we hope will demonstrate Locteron’s potential improved tolerability profile as a result of its controlled release mechanism.”

Locteron is an investigational therapeutic candidate and has not been approved for sale by the United States Food and Drug Administration or by any international regulatory agency.

About Locteron

Locteron is a controlled release interferon alpha designed to improve patient care in the treatment of hepatitis C through a more favorable side-effect profile and dosing convenience compared to existing pegylated interferon products. In contrast to Locteron’s controlled release mechanism, the currently approved products Pegasys® and PEG-Intron, and the investigational product Albuferon® are immediate release products that lack a controlled release mechanism. Interferon alpha serves as the foundation of current combination therapy for hepatitis C patients, and all major hepatitis C drug candidates currently in clinical trials are being studied in combination with interferon alpha. It is estimated that worldwide sales of interferon products for the treatment of hepatitis C will approach US$ 6 billion by 2016.

Locteron combines OctoPlus’ proprietary drug delivery technology PolyActive with BLX-883, a recombinant interferon alpha produced by Biolex in its patented LEX System(SM). Locteron is configured to allow dosing once every two weeks, more convenient than Pegasys and PEG-Intron, each of which require dosing every week. More importantly, Locteron’s controlled release mechanism results in the gradual release of interferon alpha 2b to patients over the duration of two weeks and avoids the early peak blood plasma levels of the active interferon that characterise pegylated interferons and Albuferon. This controlled release mechanism is designed to reduce the frequency, duration and severity of side effects, including flu-like symptoms, commonly experienced by patients treated with pegylated interferons and with Albuferon. Three clinical trials with Locteron have been completed, and the results of the SELECT-1 Phase IIa trial were presented at the 43rd Annual Meeting of the European Association for the Study of the Liver in April 2008.

About Biolex Therapeutics

Biolex is a clinical-stage biopharmaceutical company that uses its patented LEX System(SM) to develop hard-to-make therapeutic proteins and to optimize monoclonal antibodies. The LEX System is a novel technology that genetically transforms the aquatic plant Lemna to enable the production of biologic product candidates.

About OctoPlus

OctoPlus is a product-oriented biopharmaceutical company committed to the creation of improved pharmaceutical products that are based on OctoPlus’ proprietary drug delivery technologies and have fewer side effects, improved patient convenience and a better efficacy/safety balance than existing therapies. Rather than seeking to discover novel drug candidates through early stage research activities, OctoPlus focuses on the development of long-acting, controlled release versions of known protein therapeutics, other drugs, and vaccines on behalf of its clients.

The clinically most advanced product incorporating our technology is Biolex Therapeutics’ lead product Locteron, a controlled release formulation of interferon alpha for the treatment of chronic hepatitis C. Locteron is being manufactured for Biolex by OctoPlus and is currently in Phase IIb clinical studies.

In addition, OctoPlus is a leading European provider of advanced drug formulation and clinical scale manufacturing services to the pharmaceutical and biotechnology industries, with a focus on difficult-to-formulate active pharmaceutical ingredients.

OctoPlus is listed on Euronext Amsterdam by NYSE Euronext under the symbol OCTO. For more information about OctoPlus, please visit our website www.octoplus.nl.

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