Ricolinostat in Patients With Painful Diabetic Peripheral Neuropathy

The study includes an approximately 12 week randomized, double-blind, placebo controlled Treatment period in which patients will receive either ricolinostat or placebo, followed by an approximately 12 week open label Safety Extension period during which all patients will receive ricolinostat 120 mg daily. Prior to randomization, patients will be enrolled in a baseline Pain Observation period from Day -14 to Day -1, during which the NRS (average and worst pain) will be recorded daily using an electronic daily diary that will be completed by patients to allow patients to familiarize themselves with the pain rating procedures, and to establish a baseline and confirm eligibility to participate. Patients will also initiate daily dosing during this time to evaluate compliance eligibility for participation. A daily diary will be used by the patient to record the pain assessments and rescue medication use. A follow-up phone contact will be conducted at Day -7 to Day -5 to review diary and dosing compliance. Following the baseline Pain Observation period, patients who meet entry criteria will be randomized in a 1:1 ratio to receive either ricolinostat or placebo. During the 12-week double-blind, placebo-controlled Treatment period, patients will return for assessments in accordance with the schedule of assessments. At the conclusion of the approximately 12 week open label Safety Extension period, patients will enter a Follow-up safety washout and assessment period, which will incorporate 2 visits at approximately 2 and 4 weeks following the final Safety Extension visit, with assessments performed as outlined in the schedule of assessments.