The drug Epysqli or the version of eculizumab known as eculizumab-aagh has been available in some countries since 2024 . Although strenuous legal efforts have been made to stop it being sold in some countries by the manufacturer’s competitors. But how much is known about this eculizumab biosimilar. Global Action has searched for more information.
Samsung Bioepis’ Epysqli (eculizumab-aagh), a biosimilar to eculizumab (Soliris), has emerged as a promising alternative,.
Because Epysqli is a biosimilar medicine, the studies on effectiveness and safety of eculizumab carried out with Soliris do not all need to be repeated for Epysqli , It offers comparable efficacy at a potentially lower cost but it is not cheap.
Global Action looked at Epysqli’s effectiveness compared to eculizumab for aHUS, its side effect profile, storage requirements, and availability in countries, including those where eculizumab is not approved, with a glimpse of its access in the two largest countries, India and China.
We found that Epysqli has been designed to be highly similar to eculizumab, a monoclonal antibody used to treat aHUS.
The U.S. Food and Drug Administration (FDA) approved Epysqli in July 2024 for aHUS to inhibit complement-mediated TMA, based on robust analytical, non-clinical, and clinical data demonstrating bio similarity to eculizumab.
The European Medicines Agency had also approved Epysqli for aHUS in March 2024, with the approval for this indication based on the principle of extrapolation from clinical data in paroxysmal nocturnal hemoglobinuria (PNH), supported by the “totality-of-the-evidence.”
Clinical studies on eculizumab, demonstrated significant improvements in platelet counts and kidney function in aHUS. While specific clinical trials directly comparing Epysqli to eculizumab in aHUS patients are limited, the biosimilar’s approval relied on data showing comparable pharmacokinetics (what the body does to the drug), pharmacodynamics ( what the drug does to the body), and clinical outcomes in PNH patients, with long-term safety data up to three years.
There was a presentation at the European Society for Paediatric Nephrology (ESPN 2024) which confirmed that Epysqli’s efficacy in aHUS is supported by this extrapolation, indicating no clinically meaningful differences from eculizumab.
Real-world evidence from a Chinese cohort (2025) further supports eculizumab’s efficacy in aHUS, showing significant improvements in creatinine, estimated glomerular filtration rate (eGFR), platelets, and lactate dehydrogenase (LDH) levels, particularly when treatment is initiated within 7 days of symptom onset.
So Epysqli is considered as effective as eculizumab for aHUS, based on regulatory approvals and extrapolation from PNH data, but does it offer a cost-effective alternative?
Epysqli is priced at $4,566 per 300 mg vial, roughly a 30% discount compared to Soliris’ $6,523 per vial, offering significant cost savings for aHUS treatment. Insurance companies might be are keen to transition patients to Epysqli to reduce costs, as evidenced by precertification policies and the emphasis on biosimilars’ economic benefits by manufacturers and managed care organizations.
Though these are wholesale list prices and actual cost may be less if confidential discounts are obtained by those buying the drugs.
Epysqli patients may benefit from lower out-of-pocket costs and improved access through such payer incentives and/or assistance programmes provided by Samsung Bioepsis. Where patients get treatment through social insurance funding their national health / hospital providers may have lower care costs for aHUS in their country.
The side effect profiles of Epysqli and eculizumab are highly similar due to their biosimilarity. The most common adverse reaction reported with eculizumab in clinical trials was headache, particularly during the initial dosing phase, while the most serious is meningococcal infection (Neisseria meningitidis) due to complement inhibition.
Epysqli’s EU Summary of Product Characteristics mirrors these warnings, emphasizing the need for meningococcal vaccination at least two weeks prior to treatment or prophylactic antibiotics if vaccination is delayed.
According to FDA’s adverse events reported database – FAERS, only 7 adverse events relating to Epysqli have been reported in 2024 and 2025 to date. None relate to aHUS, 3 by PNH patients and 4 for unknown conditions. Four have been reported by Great Britain and three by France. So none in USA. Four are for off label use. Of the three on label two events related to spontaneous abortion and one to a kidney transplant.
Notably, Epysqli does not contain sorbitol, an ingredient in Soliris that can cause allergic reactions in patients with hereditary fructose intolerance, potentially giving Epysqli a slight safety advantage for certain populations, particularly children under two years old.
Both Epysqli and eculizumab are administered as intravenous injections and require specific storage conditions to maintain stability. According to the prescribing information for Soliris, eculizumab vials must be stored at 2–8°C (36–46°F) in a refrigerator and protected from light. Limited data suggest that eculizumab may remain stable for short periods (up to 24 hours) at room temperature (up to 25°C or 77°F) if unopened, but prolonged storage outside refrigeration is not recommended.
For Epysqli, the EU Summary of Product Characteristics and U.S. prescribing information similarly indicate storage at 2–8°C, with no specific guidance on stability without refrigeration. It has been reported that diluted Epysqli can stored for 3 months in a fridge or 72 hours at room temperature.
Epysqli’s availability in countries where eculizumab is not approved depends on local regulatory frameworks and Samsung Bioepis’ market strategy. Biosimilars like Epysqli are typically approved in regions with established pathways for biosimilar evaluation, such as the U.S., EU, and South Korea. Epysqli is approved in the U.S. (FDA, July 2024), EU (EC, May 2023 for PNH, March 2024 for aHUS), and South Korea (MFDS) for PNH and aHUS. In these regions, Epysqli provides a cost-effective alternative to Soliris, which is widely approved for the same indications.
In countries where eculizumab is not approved, Epysqli’s entry is unlikely without prior approval of the reference product, as biosimilar regulations typically require comparison to an approved reference biologic. However, Samsung Bioepis’ global reach (over 40 countries for its biosimilars) suggests potential for expansion into markets with unmet needs, provided regulatory hurdles are addressed. No specific data confirms Epysqli’s availability in countries lacking eculizumab approval, but its lower cost could drive demand in resource-limited settings if approvals are pursued.
India: There is no definitive evidence from any source confirming Epysqli’s approval or availability in India as of August 2025. Eculizumab (Soliris) is available in India, but its high cost limits access, and biosimilar regulations are evolving. Samsung Bioepis has not publicly announced plans to launch Epysqli in India, though its focus on accessible biologics suggests potential interest. Indian patients may access Epysqli through clinical trials or import programs if approved elsewhere, but this is speculative without regulatory confirmation.
China: Eculizumab became available in China by late 2024, and a retrospective study confirmed its use in a Western Chinese cohort for aHUS. However, no specific mention of Epysqli’s approval or availability in China has been found .
Given Samsung Bioepis’ strategic partnerships and global expansion efforts, Epysqli could be under consideration for the Chinese market, especially given the high cost of Soliris and the need for affordable options. Regulatory approval from China’s National Medical Products Administration (NMPA) would be required, and as of now, no such approval is documented.
One other point to make although there is Epysqli aHUS Registry all that the aHUS Registry has found out about eculizumab will apply to. Similarly all eculizumab discontinuation research is relevant to what happens in an Epysqli discontinuation decision.
So more is known about Epysqli to add to an earlier report ( HERE)
