Open Label Extension Study to Protocol C2/13/DR-6MP-02

By following the 2 groups of subjects, i.e, those who originally received the test formulation (80 mg DR-6MP) and are now continuing for another 12 weeks on test drug vs. those who received the reference drug (Purinethol, 1-1.5 mg/kg daily) and are now being introduced to 12 weeks of 80 mg DR6MP test drug, and monitoring the CDAI scores, immunology parameters (ex. ESR and CRP) and safety assessments (i.e., adverse events occurrences, weight changes, laboratory test results) and comparing to the parameters at extension study start, the study will effectively answer the following questions: 1. Does an additional 12 weeks of 80 mg DR6MP test drug treatment maintain or improve CDAI scores? 2. Is an additional 12 weeks of 80 mg DR6MP test drug treatment safer due to negligible drug availability systemically? 3. Can an additional 12 weeks of 80 mg DR6MP test drug treatment evoke a more effective immunological systemic response? 4. In the subset of subjects willing to undergo colonoscopy/ileoscopy, does an additional 12 weeks of 80 mg DR6MP test drug induce effective mucosal healing?