Chugai’s PiaSky Launched as Taiwan’s First Approved Subcutaneous Treatment for Paroxysmal Nocturnal Hemoglobinuria (PNH)

TOKYO, October 1, 2025 -- Chugai Pharmaceutical Co., Ltd. (TOKYO: 4519) announced that Chugai Pharma Taiwan Ltd. (CPT), a wholly-owned subsidiary of Chugai, has launched PiaSky^®, a drug created by Chugai, on October 1 for “the treatment of the patients 13 years and older with paroxysmal nocturnal hemoglobinuria (PNH) and body weight of at least 40 kg” as the first subcutaneous treatment in Taiwan. PiaSky is the first subcutaneous treatment approved in Taiwan for untreated and previously treated patients with C5 inhibitors. In Taiwan, PNH is classified as a rare disease, and PiaSky was designated as an orphan drug by the Ministry of Health and Welfare (MoHW) on April 24, 2025 and obtained an orphan drug import drug license from the Taiwan Food and Drug Administration (TFDA) on May 19, 2025.

“We are very pleased to launch PiaSky in Taiwan as a new treatment for paroxysmal nocturnal hemoglobinuria (PNH). PiaSky applies Chugai’s antibody engineering technology offering the potential for sustained efficacy with a lower dosage. The treatment of PNH is long-term, and treatment options are limited. Through this new subcutaneous administration option, we aim to contribute to reducing the burden on patients and their families and improving their quality of life,” said Yuji Habara, President of CPT.

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PiaSky Approved in Taiwan as First Subcutaneous Treatment for Paroxysmal Nocturnal Hemoglobinuria (News release issued on May 19, 2025)

https://www.chugai-pharm.co.jp/english/news/detail/20250519153000_1149.html

About PiaSky

PiaSky is a Chugai-originated anti-C5 recycling antibody^TM created with our proprietary Recycling Antibody technology. Recycling antibodies are designed to achieve pH-dependent antigen binding so that a single antibody molecule can bind with the antigen multiple times, enabling a longer efficacy compared with a conventional antibody. Additionally, by introducing surface charge modification technology, it increases the clearance rate of the antigen from the blood, enabling more efficient neutralization of the antigen compared to conventional recycling antibodies, thereby reducing the required dosage. PiaSky is designed to target C5, a key component of the complement system, and is expected to control complement activity. It is also expected to reduce the treatment burden for people with PNH and their caregivers through subcutaneous administration every 4 weeks with a small volume of medicine. Since PiaSky binds to complement C5 at a different site from existing antibody drugs, it can be an effective treatment option for people with PNH with a specific C5 gene mutation (appears in approximately 3.2% of Japanese people with PNH), which causes existing antibody drugs not to bind to C5.^1,2

PiaSky has been approved in March 2024 for the treatment of PNH and launched in May of the same year in Japan. It also obtained approval in the US in June 2024, in Europe in August 2024. In addition, clinical trials are ongoing for atypical hemolytic uremic syndrome (aHUS).

About paroxysmal nocturnal hemoglobinuria (PNH)

Paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic stem cell disease characterized by complement-mediated intravascular hemolysis, which is caused by clonal expansion of hematopoietic stem cells with mutations in genes involved in GPI anchor synthesis, including the PIG-A gene. It is caused by the clonal expansion of hematopoietic stem cells, driven by acquired mutations in the PIG-A gene.³ While symptoms may vary in each individual, there are typically two types. One is symptoms attributed to the characteristic hemolysis in PNH, such as hemoglobinuria and thrombosis. The other is hematopoietic failures similar to those associated with aplastic anemia. PNH may cause complications, including chronic kidney disease and pulmonary hypertension. In Japan, PNH is a rare disease that is listed as one of the designated intractable diseases (designated intractable disease 62). 1,121 individuals have been granted the medical care recipient certificate for PNH as of the end of 2024.⁴

Trademarks used or mentioned in this release are protected by law.

Sources

1. Fukuzawa T, et al. Long lasting neutralization of C5 by SKY59, a novel recycling antibody, is a potential therapy for complement-mediated diseases. 2017; Sci Rep 7, 1080.
2. Nishimura J et al. Genetic variants in C5 and poor response to eculizumab. N Engl J Med. 2014 Feb 13;370(7):632-9.
3. Working group for the development of the reference guide revision of diagnostic criteria and practice for paroxysmal nocturnal hemoglobinuria (PNH). Referenced Guide to Paroxysmal Nocturnal Hemoglobinuria Treatment Revised 2022.
4. Portal Site of Official Statistics of Japan website (https://www.e-stat.go.jp/). Report on Public Health Administration and Services FY2023, Accessed October 2025. (in Japanese only)