Standard of Care (SOC) With or Without CTS-1027 in Hepatitis C (HCV) Null-Responders

Placebo controlled, double-blind, multicenter study utilizing Standard of Care (SOC) in
combination with CTS-1027 in genotype 1 chronic hepatitis C (HCV) patients who were
null-responders to previous SOC therapy(ies).

Null-responders are defined as patients who failed to achieve an early virologic response
(EVR) at Week 12 during previous SOC therapy.

If, during previous SOC treatment, a patient had < 2 log decline in HCV-RNA at Week 12 but >
2 log decline in HCV-RNA at any time from Week 12 to Week 24, that patient is not a
null-responder and is excluded from study participation. If, during previous SOC treatment,
a Week 12 HCV-RNA was not obtained, the post Week 12 response must have been < 2 log decline
(and still HCV-RNA positive) in order for the patient to be defined as a null-responder.

Patients will be screened and have up to 4 weeks to qualify for study entry. During this
screening period, clinical and laboratory tests will be performed. At Week 0/Day 1,
patients will undergo centralized, stratified (based on ethnicity), randomization to one of
four treatment arms: SOC + one of three doses of CTS-1027 or SOC + placebo. Study treatment
will last 24, 48, or 60 weeks, based on each patient's response to study treatment.

The Principal Investigators, other investigative site personnel, and patients will be
blinded to the HCV-RNA results for the first 12 weeks of therapy.

At Week 12, the study treatment blind will be broken by the study's Interactive Web
Randomization System (IWRS). However, the Principal Investigators, other investigative site
personnel, patients, and Sponsor will remain blinded to treatment allocation until Week 24
(see below). Patients on SOC + placebo who do not achieve at least a 2 log decline in their
HCV-RNA at Week 12 will be automatically rolled-over into the SOC + 15 mg two times a dat
(BID) arm. The treatment duration for these patients will be 60 weeks (i.e., 12 weeks on SOC
+ placebo, followed by 48 weeks on SOC + 15 mg BID). Those patients on SOC + placebo who
achieve ≥ 2 log decline at Week 12 will continue on SOC therapy until Week 48.

Patients in the SOC + CTS-1027 arms will continue with the same treatment regimen for the
initial 24 weeks regardless of HCV-RNA changes.

At Week 24, the study blind will be formally broken. Patients in the SOC + CTS-1027 arms who
achieve ≥ 2 log HCV-RNA decline by Week 24 will continue with the same treatment regimen
they were assigned during the Double-Blind Phase for an additional 24 weeks. Patients in
the SOC + CTS-1027 15 mg BID and the SOC + CTS-1027 30 mg BID arms who achieve a <2 log
HCV-RNA decline by Week 24 will dose escalate to the next higher dose of CTS-1027 for an
additional 24 weeks. Patients in the SOC + CTS-1027 60 mg BID arm who do not achieve at
least a 2 log HCV-RNA decline by Week 24 will be discontinued from the study.

All patients will be seen 4 and 12 weeks after the end of treatment (Follow-Up Period). If a
patient's HCV-RNA is undetectable at the end of treatment, he/she will be seen for an
additional follow-up visit 24 weeks after the end of treatment.