On 6 October 2025, Comisión nacional de los mercados y la competencia, the Spanish competition authority (CNMC), blocked for the first time in its existence a proposed acquisition on merger control grounds and prohibited Curium Pharma Holding Spain, S.L.U. (Curium) from taking over Institut de Radiofarmacia Aplicada de Barcelona, S.L. (IRAB) (see, attached press release).

Curium, the self-described “world’s leading nuclear medicine company” has a range of radiopharmaceutical products for the diagnosis and treatment of several diseases, and also operates as a contract manufacturer for other companies supplying radiopharmaceuticals. For its part, IRAB also has a portfolio of radiopharmaceutical products and a contract manufacturing business. Additionally, Curium owns two cyclotrons (particle accelerators) and commercially operates five public cyclotrons distributed across Spain, while IRAB operates a single cyclotron located in Barcelona.

According to CNMC, the proposed acquisition threatened competition in the markets for the supply of prostate-specific membrane antigen (PSMA) radiopharmaceuticals (used in prostate cancer detection), where the parties would hold combined market shares reaching 80–90% and 90–100%, and in the provision of contract manufacturing services to third parties in north-eastern Spain. The ostensibly narrow product market definitions and the geographical focus on the north-eastern part of Spain stem from the very short half-life of the PSMA radiopharmaceuticals which prevents storage and limits delivery to customers outside of the immediate area in which the cyclotron produces the radiopharmaceuticals.

The anticompetitive effects resulting from the very high combined market shares were compounded by the risk of coordinated effects in the affected supply markets between Curium and Novartis-owned Advanced Accelerator Applications Ibérica (AAA). Curium’s case was not helped by the CNMC’s finding in 2021 that Curium and AAA had formed a market-sharing and bid-rigging cartel which prompted CNMC to impose a fine of EUR 5.76 million (see, Van Bael & Bellis Life Sciences News and Insights of 9 February 2021).

Curium offered a series of commitments to alleviate the CNMC’s concerns, but CNMC considered these inadequate. CNMC now has one month to refer the case to the Minister of Economy, Trade, and Enterprise which, in turn, will decide whether to have the proposed acquisition reviewed by the Council of Ministers on the basis of public interest criteria.