Idenix Pharmaceuticals (IDIX)

[DewDiligence]

After three years of Baraclude, at least 25% of Lamivudine–resistant patients have also developed resistance to Baraclude. (The breakdown is 1% during the first year, 9% during the second year, and 15% during the third year.)

http://newsroom.bms.com/index.php?s=press_releases&item=201

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The emergence of resistance [to Baraclude] increased over three years in patients in lamivudine-refractory studies.

• Viral rebound due to resistance occurred in one percent (2/192) of patients during the first year of treatment.

• Viral rebound due to Baraclude resistance occurred in an additional nine percent (14/154) of patients during the second year of treatment.

• Viral rebound due to Baraclude resistance occurred in an additional 15 percent (13/85) of patients during the third year.

• The results in these patients in years one through three were consistent with the finding that the presence of lamivudine-resistant substitutions resulted in an increase in the emergence of Baraclude resistance.
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The observed 25% figure is probably an understatement of the true underlying figure because the above calculations come from open-label extension trials and the cited numbers exclude patients who didn’t continue beyond a given time period.