To investigate the effect of repeat oral dosing of CNV2197944 75 mg tid on the pain experienced in diabetic peripheral neuropathy (DPN) as measured by changes in PI-NRS after three weeks of treatment compared to the baseline period.

A 3 week randomised crossover study to investigate the effect of repeat oral dosing of CNV2197944 75 mg tid versus placebo for on the pain experienced in diabetic peripheral neuropathy (DPN). Each 3 week treatment period is seperated by a 2 week washout period. The primary outcome measure is the change from baseline in the PI-NRS after three weeks of treatment. Secondary outcome measures include pain responder rates, clinical and patient global impressions of pain, and the Neuropathic Pain Symptom Inventory.

Inclusion Criteria:

• Male or female between 18 and 85 years of age inclusive, at the time of signing the informed consent
• Diabetes Mellitus (Type I or II)with HbA1c <9%
• Evidence of symmetrical bilateral pain in lower limbs with evidence of decreased sensation or impaired reflexes and a Michigan Neuropathy Screening -Instrument score of >3 on physical examination
• Patients with diabetic peripheral neuropathy (DPN) with pain at screening present for more than 6 months. The maximum duration of DPN will be no longer than 5 years

Exclusion Criteria:

• Patients having other severe pain, which may impair the self-assessment of the pain due to DPN
• Patients who have received nerve blocks for neuropathic pain within 4 weeks -Patients on other concomitant medications used to relieve the pain of DPN
• Patients with a documented failure to respond to a maximally tolerated dose regimen of gabapentin or pregabalin