Teijin and Merz Secure Japanese Approval for XEOMIN® in Cervical Dystonia and Blepharospasm
Key Insights
Japan's MHLW approved XEOMIN® (incobotulinumtoxinA) for cervical dystonia (search) and blepharospasm (search), marking the fourth and fifth indications for the drug in Japan.
The approval was supported by Phase III trials conducted globally by Merz Therapeutics and locally by Teijin Pharma, including a 48-week Japanese blepharospasm (search) study.
An estimated 28,000 people in Japan suffer from blepharospasm (search), with tens of thousands more affected by cervical dystonia (search), representing significant unmet need.
Japan's Ministry of Health, Labour and Welfare (MHLW) has approved XEOMIN® (incobotulinumtoxinA) for the treatment of cervical dystonia (search) and blepharospasm (search), Teijin Pharma Limited and Merz Therapeutics GmbH jointly announced on June 19, 2026. The decision adds two new indications to the botulinum neurotoxin's Japanese label, bringing the total to five authorized uses alongside upper limb spasticity, lower limb spasticity, and chronic sialorrhea.
Cervical dystonia (search) is a focal dystonia characterized by involuntary contractions of the neck muscles, resulting in abnormal or repetitive movements and postures. Blepharospasm (search), also a focal dystonia, involves excessive involuntary contractions of the muscles surrounding the eye. Both conditions significantly impact patients' quality of life. In Japan, an estimated 28,000 people suffer from blepharospasm, with tens of thousands more affected by cervical dystonia.
Clinical Evidence and Mechanism of Action
The MHLW approval rests on Phase III clinical trials conducted by Merz Therapeutics across multiple countries in Europe, North America and Asia, as well as Phase III clinical trials conducted by Teijin in Japan. For blepharospasm (search), a dedicated study in Japanese patients confirmed sustained efficacy and safety over 48 weeks of repeated injections, meeting the primary endpoint and aligning with global results.
XEOMIN® contains incobotulinumtoxinA as its sole active ingredient and is produced by removing complexing proteins during manufacturing using technology developed by Merz Pharma GmbH & Co. KGaA. The drug inhibits the release of acetylcholine from cholinergic nerve endings, thereby reducing involuntary muscle contractions. The purified formulation, free of complexing proteins, may reduce the risk of neutralizing antibody development — a clinically relevant consideration for chronic conditions requiring repeated injections over many years.
A Strategic Alliance Since 2017
The approval is the latest milestone in a partnership forged in 2017, when Teijin and Merz entered an exclusive license and co-development agreement. The alliance has systematically expanded XEOMIN®'s footprint in Japan: upper limb spasticity (2020), lower limb spasticity (2021), chronic sialorrhea (2025), and now cervical dystonia (search) and blepharospasm (search).
Masaki Taneda, President of Teijin Pharma Limited, stated: "Teijin Pharma has set a long-term vision of becoming a company that helps address the challenges faced by patients, families, and communities who require greater support, with a particular focus on rare diseases and other difficult-to-treat conditions. We are pleased that this approval for additional indications will allow us to offer an additional treatment option for patients whose daily lives can be significantly affected by these neurological conditions."
Stefan König, CEO of Merz Therapeutics, emphasized that the approval "reinforces the value of our collaboration with Teijin Pharma and our shared focus on addressing unmet needs in neurological conditions worldwide, including Japan."
Market Context
Japan's pharmaceutical market, valued at over $88 billion in 2026, is the third largest globally. The botulinum toxin segment alone is projected to exceed $700 million by 2034, with some estimates placing growth at an 11.3% compound annual growth rate. Research indicates that only about half of patients treated with existing botulinum toxins report high levels of satisfaction, with a significant minority discontinuing treatment due to unsatisfactory results or side effects — underscoring the need for additional therapeutic options in this space.