Valeant Pharmaceuticals Reports Positive Data from Pradefovir Mesylate Phase 2 Study; Phase 2 Results Show Statistically Significant Decline in HBV DNA at 10, 20 and 30 mg Doses of Pradefovir.

COSTA MESA, Calif. -- Valeant Pharmaceuticals International (NYSE:VRX) today reported 48 week results from a Phase 2 study of its oral anti-viral compound, pradefovir. Valeant is evaluating the safety and efficacy of pradefovir for the treatment of compensated chronic hepatitis B. Pradefovir is a pro-drug of adefovir that was licensed from Metabasis Therapeutics. Pradefovir uses Metabasis' HepDirect(TM) technology which enables higher concentrations of the drug in the liver, the primary site of hepatitis B viral (HBV) replication.

The Phase 2 study is an open-label, randomized, multiple dose study with 242 patients enrolled at 21 sites in the United States, Taiwan, Singapore and Korea. Approximately half of the patients had been previously treated with interferon or an antiviral and are considered to be more difficult to treat. Seventy percent of the patients were HBeAg positive. The Phase 2 study consisted of five treatment groups: pradefovir - 5, 10, 20 and 30 mg/day (QD), and Hepsera (adefovir dipivoxil) - 10 mg/day (QD), with an overall treatment duration of 48 weeks.

In the Phase 2 study, 10, 20 and 30 mg of pradefovir had a statistically superior viral load reduction compared to 10 mg of Hepsera. The study results are summarized as follows:

Pradefovir Phase 2 - Week 48 Results (all patients)
              Mean Log(10) HBV DNA Decline From Baseline
                      (Intent-to-Treat Analysis)

              Dose    Number of   Baseline     Week 48      p-Value
                       Patients      Mean    Mean Decline Compared to
                                   HBV DNA        in        Hepsera
                                  (Log(10)     HBV DNA      Control
                                  copies/mL)
---------- ---------- ---------- ----------- ------------ ------------
  Hepsera   10 mg QD      50         8.0        -4.19          N/A
---------- ---------- ---------- ----------- ------------ ------------
             5 mg QD      47         7.9        -4.09         0.83
           ---------- ---------- ----------- ------------ ------------
            10 mg QD      49         7.9        -4.84        0.007
Pradefovir ---------- ---------- ----------- ------------ ------------
            20 mg QD      48         8.0        -4.89        0.007
           ---------- ---------- ----------- ------------ ------------
            30 mg QD                                       less than
                          48         8.2        -5.54        0.001
---------- ---------- ---------- ----------- ------------ ------------

The percentage of patients with HBV DNA of less than 400 c/mL were 45 percent, 63 percent, 56 percent, and 71 percent for the pradefovir 5 mg, 10 mg, 20 mg, and 30 mg groups, respectively, and 36 percent for the Hepsera group.

No patient demonstrated an increase in serum creatinine levels over baseline of greater than or equal to 0.5 mg/dL, a marker for the severe renal toxicity associated with higher doses of adefovir. Renal safety was comparable between all treatment groups. There were no serious adverse events related to treatment. The most frequently reported adverse events were similar across all treatment groups, including Hepsera. No dose-related trends regarding safety were identified and no events resulted in a patient being withdrawn prematurely from treatment.

Timothy C. Tyson, president and chief executive officer, said, "We are excited that the strong interim data seen in the Phase 2 trial were also seen in the final 48-week analysis. In addition to the significant reductions in viral load seen at week 24, continued declines occurred through the end of the Phase 2 study, demonstrating a potentially major advantage over existing therapy. We look forward to the initiation of Phase 3 trials later this year."

Kim D. Lamon, M.D., Ph.D., president, research and development and chief scientific officer, said, "Viral load reductions in the Phase 2 study were encouraging, especially considering that baseline HBV DNA levels were relatively low. It also was remarkable that 71 percent of patients in the 30 mg cohort achieved undetectable levels of HBV DNA. The Phase 2 results could make pradefovir much more competitive with other medicines on the market or in development today. A therapy that can significantly reduce HBV DNA levels without the resistance or dose-limiting side effects encountered by other medicines will provide physicians with an important treatment alternative."

The detailed Phase 2 results will be presented at the 41st Annual Meeting of the European Association for the Study of the Liver in April 2006 in Vienna, Austria. Phase 3 pivotal trials for pradefovir are expected to begin in mid-2006.

About Hepatitis B

Hepatitis B is a potentially fatal disease that can lead to complications such as cirrhosis and liver cancer. Approximately 2 billion people worldwide are estimated to have hepatitis B, with 350-400 million people estimated to be chronically infected. According to a recent study, the HBV market currently represents more than $1 billion in annual sales, and is expected to grow to over $2.8 billion by 2012.

Pradefovir is an investigational compound that has not been found by the Food and Drug Administration (FDA) or any other regulatory agency to be safe or effective in the diagnosis, mitigation, treatment or cure of any disease or illness. It may not be sold or promoted in the United States unless and until the FDA has approved its New Drug Application. Similar restrictions apply in other countries.

About Valeant

Valeant Pharmaceuticals International (NYSE:VRX) is a global, research-based specialty pharmaceutical company that discovers, develops, manufactures and markets pharmaceutical 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 funding and conducting clinical trials. 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 the clinical trials to be prematurely terminated, clinical results that indicate continuing clinical and commercial pursuit of pradefovir is not advisable, the fact that results from Phase 2 clinical trials 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.