OBJECTIVE—The aim of this trial was to evaluate the effects of α-lipoic acid (ALA) on positive sensory symptoms and neuropathic deficits in diabetic patients with distal symmetric polyneuropathy (DSP). RESEARCH DESIGN AND METHODS—In this multicenter, randomized, double-blind, placebo-controlled trial, 181 diabetic patients in Russia and Israel received once-daily oral doses of 600 mg (n = 45) (ALA600), 1,200 mg (n = 47) (ALA1200), and 1,800 mg (ALA1800) of ALA (n = 46) or placebo (n = 43) for 5 weeks after a 1-week placebo run-in period. The primary outcome measure was the change from baseline of the Total Symptom Score (TSS), including stabbing pain, burning pain, paresthesia, and asleep numbness of the feet. Secondary end points included individual symptoms of TSS, Neuropathy Symptoms and Change (NSC) score, Neuropathy Impairment Score (NIS), and patients’ global assessment of efficacy. RESULTS—Mean TSS did not differ significantly at baseline among the treatment groups and on average decreased by 4.9 points (51%) in ALA600, 4.5 (48%) in ALA1200, and 4.7 (52%) in ALA1800 compared with 2.9 points (32%) in the placebo group (all P < 0.05 vs. placebo). The corresponding response rates (≥50% reduction in TSS) were 62, 50, 56, and 26%, respectively. Significant improvements favoring all three ALA groups were also noted for stabbing and burning pain, the NSC score, and the patients’ global assessment of efficacy. The NIS was numerically reduced. Safety analysis showed a dose-dependent increase in nausea, vomiting, and vertigo. CONCLUSIONS—Oral treatment with ALA for 5 weeks improved neuropathic symptoms and deficits in patients with DSP. An oral dose of 600 mg once daily appears to provide the optimum risk-to-benefit ratio.

OBJECTIVE To evaluate efficacy and safety of lacosamide compared with placebo in painful diabetic polyneuropathy. RESEARCH DESIGN AND METHODS Diabetic patients with at least moderate neuropathic pain were randomized to placebo or lacosamide 400 (in a slow or standard titration) or 600 mg/day over 6-week titration and 12-week maintenance periods. Primary efficacy criterion was intra-individual change in average daily Numeric Pain Rating Scale score from baseline to the last 4 weeks. RESULTS For the primary end point, pain reduction was numerically but not statistically greater with lacosamide compared with placebo (400 mg/day, P = 0.12; 600 mg/day, P = 0.18). Both doses were significantly more effective compared with placebo over the titration (P = 0.03, P = 0.006), maintenance (P = 0.01, P = 0.005), and entire treatment periods (P = 0.03, P = 0.02). Safety profiles between titration schemes were similar. CONCLUSIONS Lacosamide reduced neuropathic pain and was well tolerated in diabetic patients, but the primary efficacy criterion was not met, possibly due to an increased placebo response over the last 4 weeks.

OBJECTIVE To evaluate the efficacy and safety of actovegin in patients with diabetic polyneuropathy. RESEARCH DESIGN AND METHODS In this multicenter, randomized, double-blind trial, 567 patients with type 2 diabetes received 20 intravenous infusions of actovegin (2,000 mg/day) (n = 281) or placebo (n = 286) once daily followed by three tablets of actovegin (1,800 mg/day) or placebo three times daily for 140 days. Total symptom score (TSS) of the lower limbs and vibration perception threshold (VPT) were used as coprimary outcome measures, computed as the area under the curve (AUC) from repeated scores and divided by duration of exposure. Secondary end points included individual TSS symptoms, neuropathy impairment score of the lower limbs (NIS-LL), and quality of life (short form [SF]-36). RESULTS TSS was significantly improved during actovegin treatment compared with placebo, as assessed by AUC (−0.56 points [95% CI −0.85 to −0.27]; P = 0.0003), and from baseline to 160 days (−0.86 points [−1.22 to −0.50]; P < 0.0001). VPT (five sites per foot) decreased by 3% (95% CI 0–6; P = 0.084) with actovegin than placebo, as assessed by AUC, and by 5% (1–9; P = 0.017) after 160 days. NIS-LL sensory function, as assessed by AUC, was significantly improved with actovegin versus placebo (−0.25 [95% CI −0.46 to −0.04]; P = 0.021), as was the SF-36 mental health domain. There were no differences in the incidence of adverse events between the groups. CONCLUSIONS Sequential intravenous and oral actovegin treatment over 160 days improved neuropathic symptoms, VPT, sensory function, and quality of life in type 2 diabetic patients with symptomatic polyneuropathy.

To evaluate two definitions of response and the predictive value of baseline covariates for response to actovegin treatment in type 2 diabetic patients with symptomatic diabetic sensorimotor polyneuropathy (DSPN). Response to 6-months treatment with actovegin or placebo was defined as a clinically meaningful decline from baseline to 6months in (1) both Neuropathy Impairment Score of Lower Limbs (NIS-LL) ≥2 points and Total Symptom Score (TSS) >50% and (2) NIS-LL ≥2 points only. Nineteen baseline covariates were evaluated using separate logistic regression models and either both NIS-LL and TSS or NIS-LL response definitions. Intention-to-treat analysis included 567 patients. Actovegin treatment compared to placebo was associated with better odds of response (OR [95% CI] of 1.73 [1.21-2.48] for definition 1 and 1.94 [1.33-2.84] for definition 2). Significant interaction with actovegin treatment was noted only for baseline use of angiotensin receptor blockers (ARBs)/angiotensinogen converting enzyme inhibitors (ACEIs), resulting in a reduced treatment response (P=0.03). Actovegin treatment was associated with a clinically meaningful response in neuropathic symptoms and/or impairments in patients with symptomatic DSPN. Since only one predictor of response to actovegin treatment was identified, this drug seems an appropriate therapy for the majority of patients with DSPN.

Diabetic peripheral neuropathy is a common chronic complication of diabetes mellitus, significantly impairing well-being, quality of life and functioning of patients. The prevalence of diabetic peripheral neuropathy in the Russian Federation ranges from 0.1% to 67.2% in type 1 and from 0.1 to 42.4% in type 2 diabetes mellitus. However, based on the large-scale epidemiological studies, the true prevalence of diabetic peripheral neuropathy is much higher (50 to 70%), with its painful variant occurring in 16% to 30% of patients. Despite the fact that diabetic peripheral neuropathy remains the most common chronic complication of diabetes mellitus, its diagnosis and therapy leave much to be desired. To optimize diagnostic and treatment approaches to painful diabetic peripheral neuropathy, a group of experts representing the leading Russian professional medical associations has developed clinical guidelines for the diagnosis and rational therapy of patients with painful diabetic peripheral neuropathy. This document presents practical aspects of the clinical diagnosis of painful diabetic peripheral neuropathy and an algorithm for differential diagnosis of pain in the lower extremities in patients with diabetes mellitus. The use of symptomatic analgesics with central action, such as anticonvulsants, antidepressants and opioids, is based on the main aspects of neuropathic pain pathophysiology. The characteristics of each drug class are given, with consideration of evidence on their efficacy, tolerability, and the possibility of combination therapy. The data on the first, second, and third lines of agents is presented in accordance with several international clinical guidelines. The need for a tailored drug choice, taking into account the evidence-based data on their efficacy and safety, concomitant drug therapy, tolerability, cost and preferences of the patient, age of the patient and concomitant disorders, is emphasized.