Idenix Pharmaceuticals (IDIX)

[DewDiligence]

CC notes:

1. Results of the drug-interaction study have been discussed with NVS; by joint agreement, the results meet the pre-specified threshold to continue the NM283 program: no drug interaction and a 10-percentage point delta in PCR-negativity based on a completer (PP) analysis.

2. Of the three dropouts in the triple-combo arm, only one (GI) was deemed by the investigator to be NM-283 related. The other two (CAP, mental haziness) were deemed by the investigator to be related to peg-ifn.

3. At all time points, the triple-combination arm produced ~0.5 logs greater reduction in viral load than the SoC arm.

4. The % PCR-negative on a PP basis at 4, 8, and 12 weeks was 23%, 56%, and 72% in the triple-combination arm and 11%, 36%, and 62% in the SoC arm. Thus, the “delta” at 4, 8, and 12 weeks was 12%, 20%, and 10%. Although no forecast was given on the expected delta for SVR, NVS and IDIX obviously expect there to be a clinically-meaningful SVR delta one or they would not continue the program.

5. The next step will be a phase-2b trial with about 300 treatment-naïve patients that will test the triple combination with 200mg and 400mg of NM283 vs SoC using four distinct anti-emetic regimens. (Per the agreement between the companies, NVS will fully fund the phase-2b study.) The 400mg dose of NM283 has not been extensively tested in prior studies and hence it may provide an efficacy benefit vs 200mg; I doubt the incremental benefit will be substantial, however.

6. The new phase-2b trial is expected to be enrolled, completed, and analyzed in about one year. Thus, phase-3 for treatment-naïve patients could start in 2H08, although early 2009 might be more realistic. The phase-3 trial is expected to have 800-1200 patients.

7. As stated in prior CC’s, only quadruple therapy including NM283 and another investigational drug will be tested in treatment-refractory patients. No timeline has been given for this component of the NM283 program.

8. All told, it is clearly a positive development that the NM283 program will advance. However, it is also clear that the program remains high-risk and is several years removed from producing an approved drug.