The World Health Organisation (WHO) has issued a medical product alert regarding two batches of falsified Darzalex (daratumumab) injection. The falsified products were detected in Maldives and Mexico.
National Regulatory Authorities in both countries reported the incidents to WHO in May and June 2026. The falsified products were supplied or offered by non-authorized distributors and, in at least one case, hospitals received these falsified 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.
These products are considered falsified because they deliberately misrepresent their identity, composition, or source, said the Organisation.
"The genuine manufacturer, Janssen, has confirmed that the batch numbers on the falsified products, MYS7381 and STV1K01, are not valid. Any Darzalex product with these batch numbers should be considered falsified and not used," it added.
The Maldives Food and Drug Authority reported visible particulate matter in vials of a batch of falsified Darzalex.
The falsified drug poses a serious risk to patient safety. No laboratory testing has been conducted on these products.
"Their contents, quality, and sterility remain 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 added.
Visible particulate matter was found in at least one falsified batch, STV1K01. This signals a risk of contamination. Patients could face adverse reactions, including infections or injection-related complications.
Patients receiving falsified DARZALEX may not get appropriate treatment for their condition. This can lead to disease progression. It can also increase morbidity and mortality. Prompt detection and removal of these products from the supply chain is essential to prevent patient harm.
The Organisation advices healthcare professionals that they should report any unusual adverse events, unexpected lack of therapeutic effects, or observed quality defects associated with Darzalex to their National Regulatory Authority, National Pharmacovigilance Centre, or WHO.
It advised increased surveillance and monitoring of the supply chain in countries and regions likely to be affected by these falsified products, and specially advised for increased surveillance of the informal or unregulated market, including online platforms.
"National regulatory authorities, health authorities, and law enforcement should notify WHO immediately if these products are detected," it added.