Patients entering the treatment phase will be administered NEFECON (8 mg/day OR 16 mg/day) OR placebo for a phase of 9 months. A 3-month follow-up phase will follow on from the treatment phase, of which the first 2 weeks will be used to taper the dose of those patients that received 16 mg/day dosing to 8 mg/day, with the placebo and 8 mg/day groups receiving placebo to retain blinding.