The availability of accurate laboratory methods with which to measure circulating virus has allowed us to revise our previous approach to therapy. Indeed, there is mounting evidence from clinical trials that this is so. Combining interferon with other antivirals is also a promising alternative. Ribavirin is now being evaluated as an adjuvant to interferon. Preliminary investigations suggest that similar high sustained response rates can be achieved by this combination.
Similar trials are now in progress in Chicago and elsewhere.
These PEG-interferons hold the advantage of once weekly dosing combined with the potential of improved efficacy. These compounds are now undergoing clinical testing at Rush. Even with the best interferon treatment strategies, it is unlikely that we will achieve sustained response rates much above 50 percent. Following the lead of HIV investigators, several pharmaceutical companies are now working on the development of serine protease inhibitors. The crystal structure of the HCV serine protease enzyme has recently been described and it is likely that a prototype inhibitor will enter phase I clinical trials by 1998.