A randomized double-blind, placebo-, and active-controlled study of T-type calcium channel blocker ABT-639 in patients with diabetic peripheral neuropathic pain

Pain. 2015 Oct;156(10):2013-2020. doi: 10.1097/j.pain.0000000000000263.


T-type Cav3.2 calcium channels represent a novel target for neuropathic pain modulation. Preclinical studies with ABT-639, a peripherally acting highly selective T-type Cav3.2 calcium channel blocker, showed dose-dependent reduction of pain in multiple pain models. ABT-639 also demonstrated an acceptable safety profile at single- and multiple-dose levels evaluated in a clinical phase 1 study in healthy volunteers. The primary objective of this phase 2, multicenter, randomized, double-blind, placebo-controlled, and active-controlled study was to compare the analgesic efficacy and safety of ABT-639 with placebo in the treatment of diabetic neuropathic pain. Pregabalin, an approved treatment for painful diabetic neuropathy, was included as a positive control. A total of 194 patients were randomized and treated for 6 weeks; 62 patients received ABT-639 (100 mg twice daily), 70 patients received pregabalin (150 mg twice daily), and 62 patients received placebo. When assessing the mean changes from baseline in patient-recorded pain scores at the end of week 6, there was no significant difference observed for ABT-639 compared with placebo (-2.28 vs -2.36; P = 0.582). Pregabalin treatment resulted in a transient improvement in pain compared with placebo, which did not persist throughout the study. There were no significant safety issues identified with ABT-639. A majority of adverse events were considered mild to moderate in intensity. In conclusion, treatment with the highly selective T-type Cav3.2 calcium channel blocker ABT-639 100 mg twice daily for 6 weeks showed no safety signals that would preclude further investigation but did not reduce neuropathic pain in patients with diabetes (ClinicalTrials.gov identifier: NCT01345045).

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Calcium Channel Blockers / pharmacokinetics
  • Calcium Channel Blockers / therapeutic use*
  • Diabetic Neuropathies / drug therapy*
  • Diabetic Neuropathies / psychology
  • Double-Blind Method
  • Female
  • Heterocyclic Compounds, 2-Ring / pharmacokinetics
  • Heterocyclic Compounds, 2-Ring / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Pain Measurement
  • Quality of Life / psychology
  • Sulfonamides / pharmacokinetics
  • Sulfonamides / therapeutic use*
  • Treatment Outcome
  • Young Adult


  • 4-chloro-2-fluoro-N-(2-fluorophenyl)-5-(hexahydropyrrolo(1,2-a)pyrazin-2(1H)-ylcarbonyl)benzenesulfonamide
  • Calcium Channel Blockers
  • Heterocyclic Compounds, 2-Ring
  • Sulfonamides

Associated data

  • ClinicalTrials.gov/NCT01345045