Patients in the treatment extension phase, who experience a flare post their last dose and require treatment, may receive a dose of LFG316. These patients will be assessed for a response at their next PRN visit as scheduled by the investigator. Visit frequency is determined by the investigator. If they continue to respond to LFG316 therapy, they may remain in the PRN treatment arm. They may receive up to 7 additional doses of LFG316 in the PRN period. Throughout the trial LFG316 will not be administered more frequently than monthly.