A British pharmaceutical company is reporting positive results from a Phase II study of a new drug in patients with trigeminal neuralgia (TGN), a rare and severe form of facial pain.
Convergence Pharmaceuticals said the drug – a sodium channel blocker known as CNV101480 – significantly reduced the severity of pain and the number of sudden attacks (paroxysms) in TGN patients. Pain severity decreased by 55% and the number of paroxysms decreased by an average of 60% when compared to a placebo.
“Having worked in the field of TGN for over 20 years and managed hundreds of patients with this severe facial pain it is wonderful news to find that there is potentially a new drug to add to our armory which not only is effective but is also so well tolerated,” said Professor Joanna M. Zakrzewska, an expert in the field of facial pain at University College London Hospitals NHS Foundation.
“This is the first time that we have a drug specifically being trialed in TGN rather than using a previously developed anti-epileptic drug.”
A total of 67 patients with TGN participated in the study. Following an initial 21-day treatment period with CNV1014802, patients who showed a reduction in the number and severity of paroxysms were then randomly assigned to a 28-day double-blind treatment period with either CNV1014802 or a placebo.
CNV1014802 was well tolerated with no serious adverse events. The full study will be published at the International Association for the Study of Pain’s (IASP) World Congress of Pain in Buenos Aires , Argentina in October 2014.
CNV1014802 received orphan-drug designation from the Food and Drug Administration in 2013. Convergence said it will use data from the Phase II study to design a pivotal clinical study to start in early 2015, with the goal of commercializing the drug “as soon as possible.”
There have been very few well-controlled, randomized, placebo-controlled studies in trigeminal neuralgia, and the majority of drugs have had other primary uses. Due to the severity of the pain, it is not always practical or ethical to conduct a traditional placebo-controlled study.
Trigeminal neuralgia is a severe facial pain condition. Current guidelines for treating TGN recommend sodium channel blockers — carbamazepine or oxcarbazepine — as the first line of treatment. However, the drugs often have severe side effects, especially cognitive ones, and often interact with other medications.
“This is the first well powered, randomized and placebo controlled clinical trial to demonstrate efficacy of a selective state dependent Nav1.7 inhibitor in a chronic pain indication. This follows years of intensive research and provides huge promise for a better standard of treatment for TGN in the future,” the company said in a statement.
TGN is a very severe form of facial pain that usually involves sudden and severe episodes of pain, usually on one side of the face, which can be provoked by a light touch or even a breeze. The pain follows one or more branches of the trigeminal nerve, which provides nerve sensation in the mouth, face and the front of the scalp. The severity of the pain and its unpredictability can lead to significant depression or even suicide.
TGN affects about 50,000 people in the U.S alone. The majority of TGN sufferers are over 50 years of age, although cases have been reported in young adults. TGN is more common in women than in men, and for most sufferers, the condition is progressive and worsens over time.