Eisai and Biogen have jointly announced the approval of Leqembi intravenous infusion (lecanemab) for the treatment of Alzheimer's disease (AD) in Japan. Leqembi has been granted approval for the purpose of slowing the progression of mild cognitive impairment (MCI) and mild dementia associated with AD.
Leqembi is a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody designed to target aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ), a protein closely linked to AD. It stands as the first and only approved treatment capable of reducing the rate of disease advancement and slowing cognitive and functional decline by selectively binding to and eliminating the most toxic Aβ aggregates, known as protofibrils, which contribute significantly to the neurotoxicity observed in AD.
Japan's approval of Leqembi follows the traditional approval it received in the United States in July 2023, making it the second country to grant this approval.
The decision to approve Leqembi in Japan is rooted in the results of the Phase 3 Clarity AD clinical trial conducted by Eisai. In this extensive global trial, Leqembi not only met its primary endpoint but also demonstrated significant statistical benefits across all key secondary endpoints, providing clear clinical evidence of its efficacy. The primary endpoint measured the global cognitive and functional scale known as the Clinical Dementia Rating Sum of Boxes (CDR-SB). Over an 18-month period, treatment with Leqembi led to a 27% reduction in clinical decline on the CDR-SB scale compared to a placebo.
In response to this approval, Eisai has committed to conducting a post-marketing special use results survey (all-case surveillance) for all patients administered with Leqembi. This survey will continue until a certain amount of patient data is gathered post-launch, in accordance with the conditions set by the Ministry of Health, Labour, and Welfare. Additionally, Eisai will promote the appropriate use of Leqembi as specified in the package insert and will develop training materials for healthcare professionals to aid in the management and monitoring of amyloid-related imaging abnormalities (ARIA).
Eisai leads the global development and regulatory submissions for Leqembi, with both Eisai and Biogen jointly involved in commercializing and promoting the product. In Japan, Eisai and Biogen Japan will collaborate on the promotion of Leqembi, with Eisai serving as the Marketing Authorization Holder for the product. This partnership underscores their commitment to providing innovative solutions for Alzheimer's disease and enhancing the quality of life for patients and their caregivers.
UCB has received approval from the Japanese Ministry of Health, Labour and Welfare (MHLW) for Rystiggo (rozanolixizumab) and Zilbrysq (zilucoplan) to treat adult patients with generalized myasthenia gravis (gMG). Rystiggo and Zilbrysq have different mechanisms of action and are now available for patients who have not responded adequately to steroids or other immunosuppressants. This decision makes Japan the first country in the world to approve Rystiggo and Zilbrysq simultaneously, presenting a choice for physicians and patients in the Japanese gMG community.
Rystiggo is a humanized IgG4 monoclonal antibody designed to target adult patients with gMG. It binds to the neonatal Fc receptor (FcRn) and is indicated for those inadequately responding to other treatments.
On the other hand, Zilbrysq represents a significant advancement as the first once-daily subcutaneous (S.C.) therapy for gMG that specifically inhibits complement component 5 (C5). This novel treatment can be self-administered by adult patients, enhancing their independence and convenience.
These approvals are based on pivotal phase 3 data for both medications, demonstrating statistically and clinically relevant improvements in gMG-specific outcomes. Zilbrysq, as a C5 inhibitor, effectively prevents complement-mediated damage to the neuromuscular junction. Its unique feature of self-administration through subcutaneous injection provides added benefits, including reduced travel time to hospitals and increased patient autonomy. Moreover, unlike monoclonal antibody C5 inhibitors, zilucoplan can be used concurrently with intravenous immunoglobulin and plasma exchange without needing supplemental dosing.
Rozanolixizumab acts by significantly reducing circulating IgG levels.
Zilbrysq trial outcomes:
The approval of Zilbrysq (zilucoplan) in Japan is supported by data from the Phase 3 RAISE study (NCT04115293), published in The Lancet Neurology in May 2023. The study's primary endpoint, the Myasthenia Gravis-Activities of Daily Living (MG-ADL) score, showed a statistically significant and clinically meaningful improvement with zilucoplan compared to placebo. Zilbrysq showed considerable improvement (−4.39) versus placebo (−2.30).
Rystiggo trial outcomes:
The approval of Rystiggo in Japan to treat generalized myasthenia gravis (gMG) in adult patients, specifically those who have not responded effectively to steroids or other immunosuppressants, is substantiated by compelling safety and efficacy data derived from the pivotal Phase 3 MycarinG study (NCT03971422).
The primary focus of this study was to assess the efficacy of Rystiggo by comparing the change from baseline in the MG-ADL total score at Day 43. The results revealed significant improvements in MG-ADL scores from baseline to Day 43, particularly in the groups receiving rozanolixizumab at doses of 7 mg/kg (with a least-squares mean change of –3.37) and 10 mg/kg (with a least-squares mean change of –3.40 ) in contrast to the placebo group (with a change of –0.78).
GSK has announced that Japan's Ministry of Health, Labour and Welfare (MHLW) has approved an expanded indication for Shingrix (Recombinant Zoster Vaccine, Adjuvanted - RZV) to prevent shingles in adults aged 18 and over who are at increased risk of the condition. Shingrix was initially approved in 2018 for adults aged 50 and over. This approval significantly increases the availability of RZV in Japan, offering protection to all adults considered at higher risk by their healthcare providers.
Shingles, caused by the varicella-zoster virus (VZV), can reactivate in individuals with dormant VZV in their nervous system, particularly as they age. The immune system's response to infection weakens with age, elevating the risk of shingles.
It is estimated that around 600,000 people in Japan develop shingles annually.
The MHLW approval was based on data from six clinical trials involving adults aged 18 and over who were considered at increased risk of shingles, such as those who underwent recent stem cell or kidney transplants, had blood cancer, solid tumours, or HIV.
Shingles typically manifest as a painful rash with chest, abdomen, or face blisters.
Shingrix is a non-live, recombinant sub-unit vaccine that combines an antigen called glycoprotein E with an adjuvant system known as AS01B. It helps address the decline in the immune response to immunization associated with ageing, thereby improving protection against shingles in older adults. Shingrix does not prevent primary varicella infection (chickenpox).