Valeant Pharmaceuticals to Initiate Retigabine Phase 3 Clinical Trials; Retigabine Represents the First in a New Class of Epilepsy Treatments; First of Two Phase 3 Studies to Initiate Enrollment in Third Quarter of 2005.

COSTA MESA, Calif. -- Valeant Pharmaceuticals International (NYSE:VRX) today announced that it intends to initiate enrollment in the third quarter of 2005, for a Phase 3 trial for retigabine, which is being developed as an adjunctive treatment for partial-onset seizures in patients with epilepsy. The trial is one of two pivotal Phase 3 trials that Valeant intends to initiate in 2005. Enrollment in the second trial is expected to begin in the fourth quarter of 2005. The decision to initiate these trials follows a consultation with the Food and Drug Administration (FDA) regarding the Phase 3 protocol design, which was submitted to the FDA as part of a special protocol assessment.

"Retigabine is a pipeline candidate with significant potential in the $8.7 billion epilepsy market," Valeant's president and chief executive officer, Timothy C. Tyson said. "Retigabine represents an entirely new mechanism of action for the treatment of partial onset seizures. With potential for more than $500 million in peak sales in the treatment of epilepsy alone and the possibility of seeking further indications, retigabine is an excellent addition to our robust late-stage pipeline that also includes Viramidine(R), pradefovir and Zelapar(TM)."

Retigabine works as both a potassium-channel opener and a potentiator of gamma aminobutyric acid (GABA). This new mechanism is a potentially major advancement in the treatment of partial onset seizures and may be a key differentiating factor in the treatment of epilepsy where combination therapy is common.

The Phase 3 clinical trials for retigabine will consist of two global studies -- the first in the United States, Mexico and South America with up to 45 sites, and the second in other major markets around the world with up to 60 sites. Combined enrollment in both studies is expected to be approximately 800 patients. The first study will have two treatment arms: placebo and 1,200 mg/day; the second study will have three arms: placebo, 600 mg/day and 900 mg/day.

Results of the two studies are anticipated to be available in the second half of 2007. Phase 3 is the last phase in a multi-phase clinical evaluation that may lead to the filing of a New Drug Application. Retigabine is expected to be in the market in 2008 assuming successful completion of the Phase 3 trials and approval from the FDA.

The studies will consist of randomized, double-blinded, placebo-controlled, multi-center, parallel groups and will assess the efficacy and safety of retigabine compared to placebo in patients with epilepsy who are receiving one, two or three antiepileptic drugs (AEDs). The two co-primary endpoints that will be assessed with equal priority are: 1) the percentage change in total partial seizure frequency per four weeks from baseline to the double-blind period, and 2) the proportion of responders, where a "responder" is defined as a patient experiencing a greater than or equal to 50 percent reduction in total partial seizure frequency per four weeks from baseline to the double-blind period.

A large Phase 2 clinical trial for retigabine has previously been completed and was accepted as a well-controlled trial by the FDA. Details of the Phase 2 trial are expected to be presented at the 18th World Congress of Neurology in November 2005, and at the American Epilepsy Society in the fourth quarter of 2005. The study consisted of four treatment groups: a placebo group and retigabine 600 mg/day, 900 mg/day and 1,200 mg/day groups. The median monthly seizure rates decreased by 13 percent in the placebo group and 23 percent, 29 percent and 35 percent in the retigabine groups. Results were statistically significant in the two higher doses compared to placebo (p less than 0.001).

Safety results were similar in nature and frequency to those observed with other AEDs. The most frequently observed adverse events occurred during the titration period and were related to the central nervous system. The most common adverse events affecting the central nervous system were somnolence, dizziness, confusion, speech disorder, vertigo, tremor, amnesia, thinking abnormality, abnormal gait, incoordination, ataxia, and paresthesia.

Valeant also announced that it has appointed Quintiles Transnational as its clinical research organization partner for the Phase 3 clinical trials. Quintiles has offices in 50 countries and is one of the world's leading pharmaceutical services organizations.

Retigabine has not been proven safe or effective in the diagnosis, treatment, or prevention of any disease or illness, or approved by the FDA or any corresponding foreign regulatory agency. Until such time as Valeant receives approval to market retigabine, it may not be sold or offered for sale in the United States or abroad.

About Epilepsy

According to the Epilepsy Foundation, Epilepsy is one of the most common neurological diseases, with epilepsy and seizures affecting 2.5 million Americans of all ages, at an estimated annual cost of $12.5 billion in direct and indirect costs. Approximately 181,000 new cases of seizures and epilepsy occur each year, with 10 percent of the American population experiencing seizure in their lifetime.

Approximately 30 percent of patients are refractory to existing agents, and many patients who respond favorably to treatment endure serious side effects that detract from their quality of life.

IMS estimates the current epilepsy market is about $8.7 billion globally. IMS projects that the U.S. market will grow 6.6 percent and the EU market will grow 8.0 percent to 2018.

About Valeant

Valeant Pharmaceuticals International (NYSE:VRX) is a global, publicly traded, research-based specialty pharmaceutical company that discovers, develops, manufactures and markets products primarily in the areas of neurology, infectious disease and dermatology. More information about Valeant can be found at www.valeant.com.

FORWARD-LOOKING STATEMENTS

This press release contains forward-looking statements within the meaning of the federal securities laws relating to expectations, plans or prospects for Valeant Pharmaceuticals, including our ability to obtain approval of retigabine and other pipeline candidates within the company's estimated timeline or at all and to achieve estimated sales. These statements are based upon the current expectations and beliefs of Valeant Pharmaceuticals' management and are subject to certain risks and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. These risks and uncertainties include market conditions and other factors beyond Valeant Pharmaceuticals' control, adverse events that would require clinical trials to be prematurely terminated, clinical results that indicate continuing clinical and commercial pursuit of retigabine is not advisable, the fact that Phase 2 clinical trial results are not always indicative of those seen in Phase 3 clinical trials, and the risk factors and other cautionary statements discussed in Valeant Pharmaceuticals' filings with the U.S. Securities and Exchange Commission.