The study will enroll CKD patients who completed the 12-week Phase II study, including a maximum of 115 patients at five sites. Subjects will be randomly assigned 1:1 to treatment with 1.5 mg/m2 GCS-100 or 30 mg/m2 GCS-100. All doses of study drug will be administered intravenously once weekly for as long as eight consecutive weeks with a four-week follow-up period and then at least once a month for a total of one year.
The primary objective of the extension study is to determine the safety and tolerability of extended dosing with GCS-100. The secondary objective will be to determine the efficacy as measured by eGFR of GCS-100 administered for eight weeks relative to the effect of eight weeks of treatment for the same patient on the initial study, including those who were on placebo. This study also provides the opportunity to compare crossover data for individual patients from the initial Phase II study and this extension study. Initial data from this study is expected to be available in March 2014.
GCS-100 is a complex polysaccharide that has the ability to bind to and block the effects of galectin-3.