The World Health Organization (WHO) has issued a Medical Product Alert warning healthcare providers, regulators and the public about two batches of falsified DARZALEX (daratumumab) injection that have been detected in the Maldives and Mexico.
The incidents were reported to WHO by the national regulatory authorities of both countries in May and June 2026.
According to the organization, the falsified medicines were supplied or offered by non-authorized distributors, and in at least one case, hospitals received the counterfeit products.
DARZALEX is a monoclonal antibody used to treat rare blood disorders and cancers that affect bone marrow, specifically multiple myeloma and amyloid light-chain (AL) amyloidosis.
WHO said the falsified products deliberately misrepresent their identity, composition or source.
The genuine manufacturer, Janssen, has also confirmed that the batch numbers on the falsified products, MYS7381 and STV1K01, are invalid, cautioning that any DARZALEX product bearing these batch numbers should be considered falsified and not used.
In addition, the Maldives Food and Drug Authority reported visible particulate matter in vials from batch STV1K01.
Serious patient safety risks
WHO warned that the falsified DARZALEX injections pose a serious risk to patient safety because their contents, quality and sterility are unknown. “They may contain no active ingredient. They may contain the wrong ingredients or harmful substances. As a result, these products may be ineffective or harmful,” it said.
The organization further cautioned that the presence of visible particulate matter indicates a potential contamination risk, which could lead to adverse reactions, including infections or injection-related complications.
Patients receiving falsified DARZALEX may not get appropriate treatment for their condition, potentially leading to disease progression, increased morbidity and even mortality.
WHO stressed that prompt detection and removal of these products from the supply chain is essential to prevent patient harm.
WHO calls for heightened surveillance
WHO has urged healthcare professionals to report any unusual adverse events, unexpected lack of therapeutic effects or observed quality defects associated with DARZALEX to their national regulatory authority, pharmacovigilance centre or directly to WHO.
The agency also called on national regulators, health authorities and law enforcement agencies to strengthen surveillance of pharmaceutical supply chains, particularly the informal and unregulated market, including online platforms, and to notify WHO immediately if the falsified products are detected.
Patients and healthcare providers are advised not to use any DARZALEX products bearing batch numbers MYS7381 or STV1K01.
WHO also reminded the public to obtain medicines only from authorised and licensed suppliers and advised anyone who may have used the falsified products or experienced adverse effects after use to seek immediate medical attention.
