Valeant Pharmaceuticals Presents Positive Interim Data on Pradefovir Mesylate at AASLD; 24-Week Interim Results Show Pradefovir Statistically Better Than Hepsera

Valeant Pharmaceuticals International (NYSE:VRX)yesterday afternoon presented interim results from a Phase 2 study ofits oral anti-viral compound, pradefovir mesylate, at the 56th AnnualMeeting of the American Association for the Study of Liver Diseases(AASLD) in San Francisco. Interim 24-week data show that thepercentage of patients achieving undetectable HBV DNA (less than 400c/mL) was significantly greater for patients receiving pradefovircompared to those receiving Hepsera (adefovir dipivoxil) at doses of10mg, 20mg and 30mg QD. In addition, these data show that thepradefovir 30mg QD cohort achieved a 5.02 log10 drop in viral titersfrom baseline compared to a 3.66 log10 drop in the Hepsera group (pless than 0.001).

Pradefovir is a pro-drug of adefovir that was licensed fromMetabasis Therapeutics. Pradefovir uses Metabasis' HepDirect(TM)technology that enables higher concentrations of the drug in theliver, the primary site of hepatitis B viral (HBV) replication.

"The 24-week interim results are excellent. These data suggestthat pradefovir has the potential to be a 'best in class' option forthose suffering from hepatitis B," said Kim D. Lamon, M.D., Ph.D.,Valeant's president, research and development and chief scientificofficer. "We continue to be encouraged by these interim results andlook forward to pradefovir being highly competitive in this class ofdrugs."

The Phase 2 study is an open-label, randomized, multiple dosestudy with 242 patients enrolled at 21 sites in the United States,Taiwan, Singapore and Korea. Approximately half of the patients hadbeen previously treated ineffectively with other drugs and 70 percentof the patients were HBeAg positive. Patients who have been previouslytreated ineffectively are considered to be more difficult to treat.The Phase 2 study consists of five treatment groups: pradefovir -- 5,10, 20 and 30 mg/day (QD), and Hepsera -- 10 mg/day (QD), with anoverall treatment duration of 48 weeks.

The interim 24-week data indicate that pradefovir resulted indifferences in the percentage of patients achieving undetectable HBVDNA summarized as follows:
Pradefovir Phase 2 - Interim Week 24 Results (all patients)
Percent of Patients less than 400 c/mL

Dose HBeAg (+) HBeAg (-)
---------- --------- ----------------------- -------------------------
N Median % less N Median % less
Baseline than Baseline VL than
VL 400c/mL (Log10 c/mL) 400c/mL
(Log10 by week by week
c/ml) 24 24
---------- --------- --- ---------- -------- --- ----------- ---------
Hepsera 10 mg QD 36 8.3 8% 14 6.7 36%
---------- --------- --- ---------- -------- --- ----------- ---------
5 mg QD 33 8.4 3% 14 6.8 50%
--------- --- ---------- -------- --- ----------- ---------
10 mg QD 33 8.7 15% 16 7.0 44%
Pradefovir --------- --- ---------- -------- --- ----------- ---------
20 mg QD 31 8.7 23% 17 6.9 41%
--------- --- ---------- -------- --- ----------- ---------
30 mg QD 36 8.6 31% 12 7.8 58%
---------- --------- --- ---------- -------- --- ----------- ---------

As previously noted, the interim 24-week data indicate thatpradefovir demonstrated a significant decline in HBV DNA summarized asfollows:
Pradefovir Phase 2 - Interim Week 24 Results (all patients)
Mean Log10 HBV DNA Decline From Baseline
(Intent-to-Treat Analysis)

Dose Number of Baseline Week 24 p-Value
Patients Mean Mean Decline Compared
HBV DNA in to
(Log10 c/mL) HBV DNA Hepsera
(Log10 c/mL) Control
---------- ------------ ---------- ------------ ------------ ---------
Hepsera 10 mg QD 50 8.0 -3.66 N/A
---------- ------------ ---------- ------------ ------------ ---------
5 mg QD 47 7.9 -3.39 0.262
------------ ---------- ------------ ------------ ---------
10 mg QD 49 7.9 -4.22 0.012
Pradefovir ------------ ---------- ------------ ------------ ---------
20 mg QD 48 8.0 -4.33 0.004
------------ ---------- ------------ ------------ ---------
less than
30 mg QD 48 8.2 -5.02 0.001
---------- ------------ ---------- ------------ ------------ ---------

The interim results have shown no evidence of nephrotoxicity.There were no serious adverse events related to treatment. The mostfrequently reported adverse events were similar across all treatmentgroups, including Hepsera. No dose-related trends regarding safetywere identified and no events resulted in a patient being withdrawnprematurely from treatment.

Patient participation in the Phase 2 trial is expected to becompleted early in 2006. Valeant has reviewed interim 24-week resultsfrom the Phase 2 trial with the Food and Drug Administration (FDA) andintends to initiate Phase 3 trials in mid-2006.

Pradefovir is an investigational compound that has not been foundby the FDA or any other regulatory agency to be safe or effective inthe diagnosis, mitigation, treatment or cure of any disease orillness. It may not be sold or promoted in the United States unlessand until FDA has approved its New Drug Application. Similarrestrictions apply in other countries.

About Hepatitis B

Hepatitis B is a potentially fatal disease that can lead tocomplications such as cirrhosis and liver cancer. Approximately 2billion people worldwide are estimated to have hepatitis B, with350-400 million people estimated to be chronically infected. Accordingto a recent study, the HBV market currently represents more than $1billion in annual sales, and is expected to grow to over $2.8 billionby 2012.

About Valeant

Valeant Pharmaceuticals International (NYSE:VRX) is a global,publicly traded, research-based specialty pharmaceutical company thatdiscovers, develops, manufactures and markets pharmaceutical productsprimarily in the areas of neurology, infectious disease anddermatology. More information about Valeant can be found atwww.valeant.com.

All trademarks are the trademarks or the registered trademarks oftheir respective owners.

FORWARD-LOOKING STATEMENTS

This press release contains forward-looking statements within themeaning of the federal securities laws relating to expectations, plansor prospects for Valeant Pharmaceuticals, including funding andconducting clinical trials. These statements are based upon thecurrent expectations and beliefs of Valeant Pharmaceuticals'management and are subject to certain risks and uncertainties thatcould cause actual results to differ materially from those describedin the forward-looking statements. These risks and uncertaintiesinclude market conditions and other factors beyond ValeantPharmaceuticals' control, adverse events that would require theclinical trials to be prematurely terminated, clinical results thatindicate continuing clinical and commercial pursuit of pradefovir isnot advisable, the fact that Phase 2 interim clinical trial resultsmay not be indicative of results from completed Phase 2 clinicaltrials, and that the results from completed Phase 2 clinical trialsare not always indicative of those seen in Phase 3 clinical trials,and the risk factors and other cautionary statements discussed inValeant Pharmaceuticals' filings with the U.S. Securities and ExchangeCommission.