Merck (NYSE:MRK)
- Interim results from ongoing phase 2 study show 97% cure rate in Genotype-1 patients
- Chirrotic and non-chirrotic patients both show high sustained viral response at 12 weeks (SVR12)
- results comparable to Gilead's sofosbuvir
- Merck starting phase 3 trials based on these results
Phase-2 results show promise
Merck reported interim results from the ongoing phase 2 "C-Worthy" clinical trials of difficult-to-treat genotype 1 (GT-1) hepatitis c (HCV) patients at the European Association for the Study of the Liver (EASL) meeting this week. For GT-1 patients given Merck's investigational compounds MK-5172 and MK-8742 (an NS 3/4A protease inhibitor and and NS5A replication complex inhibitor respectively) sustained viral responses were achieved at 12 weeks for 98% of patients given MK-5172/MK-8742 alone and in 94% of patients given MK-5172/MK-8742 plus ribavarin.
In a further analysis of study data, MRK revealed that difficult to treat patients - those who are treatment naive but have liver cirrhosis, prior-null responder patients with and without cirrhosis and HIV/HCV co-infected patients had sustained viral responses at 12 weeks or between 90% and 100%
Comparison to Sofosbuvir
The key metric for any new potential therapy for HCV is how it compares to Gilead Sciences' (NASDAQ:GILD) newly approved Sofosbuvir (trade name SOVALDI). Keep in mind caveats that cross trial comparisons are difficult due to the vastnumbers of parameters that can vary across trials, and the fact that MRK's results are phase 2 results and larger phase 3 trials will likely show slightly lower SVR rates. SOVALDI plus ribavarin showed SVR rates of 89% across all GT-1 patients. MRK's results so far appear slightly better; however, it is important to remember that SOVALDI is also approved to treat HCV genotypes 2 through 6. Furthermore, in GILD's presentations at EASL, the company revealed new phase 2 data showing that SOVALDI plus a new pan-genotypic NS5A inhibitor GS-5816 showed SVR-12 of 96.1%
Merck Starting Phase 3
Merck has indicated that, on the basis of the interim results from thephase 2 C-WORTHy trials, the company is initiating phase 3 trials (dubbed C-EDGE) with the intention of filing for approval in 2015. Consensus analyst estimates only allocate $450 million in HCV revenues to MRK in out-years. it is likely that these consensus numbers will have to be increased if these strong cure rates are maintained in larger phase 3 studies. Overall it is likely that MRK will give SOVALDI some competition for GT-1 patients.
