Introduction and historical context
In a decision of rare consequence, Spain's National Markets and Competition Commission (CNMC) has moved to propose the prohibition of Curium Pharma Holding Spain's proposed acquisition of Institut de Radiofarmàcia Aplicada de Barcelona (IRAB)1. The ruling, unprecedented in the authority's history, marks the first the CNMC, in its current form, has moved to prohibit a merger outright—although its predecessor, the Tribunal de Defensa de la Competencia (TDC), blocked two transactions under the prior regime2.
At the heart of the decision lies the authority's conclusion that the transaction would materially restrict effective competition in two interlinked markets: the supply of PET radiopharmaceuticals—most notably PSMA tracers essential to prostate cancer diagnostics—and the provision of contract manufacturing services for such products in northeastern Spain.
The CNMC determined that the merger would consolidate extraordinarily high market shares, eliminate the only independent manufacturer in the region with cyclotron3 capacity, and heighten the risk of coördination between the remaining operators. In practical terms, the transaction would transform a fragile competitive equilibrium into a durable regional duopoly, with predictable consequences for price, innovation, and hospital choice.
Markets in play: Where physics defines the boundaries of competition
The CNMC's analysis turned on an unusual interplay between physics and economics. The authority distinguished two relevant product markets. The first concerns the production and supply of PET radiopharmaceuticals—principally 18F-FDG, used across a wide spectrum of oncological imaging, and PSMA tracers, which are indispensable in the diagnosis and follow-up of prostate cancer. The second market encompasses the provision of contract manufacturing services for these radiopharmaceuticals to third parties that lack their own production facilities.
In defining the geographic dimension of competition, the CNMC took a resolutely empirical view. Because these compounds decay within hours and cannot be stored or transported over long distances, the practical reach of each producer is confined to the operating radius of its cyclotron. Accordingly, the authority concluded that the relevant markets are regional—concentrated in northeastern Spain, and more precisely in Catalonia—where IRAB's cyclotron represents the sole independent source of supply. In this industry, competition fades not with regulation but with the half-life of the isotope itself; market power, in short, is bounded by the laws of physics.
Theory of harm
The CNMC found that the proposed merger would combine the only two meaningful sources of PET radiopharmaceutical production in northeastern Spain, yielding combined market shares that in some segments approached one hundred percent. In particular, Curium and IRAB together accounted for nearly the entirety of PSMA tracer production in the region—an area where each additional minute of radioactive decay translates directly into diminished competitive reach.
The authority also identified serious vertical effects. IRAB had functioned as the sole independent contract manufacturer with cyclotron capacity available to third parties. Its absorption by Curium would close off a vital pathway for potential entrants—new laboratories seeking to develop or commercialise alternative tracers—by depriving them of access to essential production infrastructure. The result, in the CNMC's view, would be a structural foreclosure of opportunity in a market already defined by scarcity and steep technological barriers.
Moreover, the authority's concerns are not purely theoretical. It recalled prior episodes of collusive conduct within the radiopharmaceutical sector, including a 2021 case in which Curium and another operator were sanctioned for market sharing and bid-rigging4. Against that background, the prospect of a post-merger duopoly commanded special vigilance. The CNMC concluded that the merger would create not only the ability but also the incentive to coördinate competitive behaviour—an alignment of conditions that European competition authorities are trained to regard as the classic precursor to harm.
Entry, expansion, and the unforgiving math of half life
While Curium argued that new radiopharmaceuticals—particularly gallium-based PSMA tracers—were poised to enter the Spanish market, the CNMC viewed such prospects as more theoretical than real. Entry, the authority observed, is constrained not by regulation alone but by the immutable laws of time and physics. Producing and distributing PET radiopharmaceuticals requires access to a functioning cyclotron, validated production processes, a reliable logistics chain, and an established commercial network with hospitals—all within the narrow window before radioactive decay renders the product unusable.
In such an environment, the mere grant of marketing authorisations is insufficient to generate competitive pressure. A newcomer without a nearby cyclotron is effectively excluded; every additional kilometer of distance erodes viability, and every hour of delay annihilates value. The CNMC thus reasoned that new entrants could not, in practice, offset the loss of IRAB's independent presence in northeastern Spain. The barriers were not only economic but temporal. As one might say in this peculiar market, competition itself is subject to half-life decay.
An exceptional case for structural remedies
Curium proposed a comprehensive package of behavioural commitments, including maintaining IRAB's manufacturing operations for a transitional period, granting access to contract manufacturing services, and expanding certain production lines. These measures reflected a pragmatic attempt to address the CNMC's concerns and, in many industries, such commitments have proven effective in preserving competitive dynamics without resorting to structural divestitures.
However, the CNMC concluded that in this particular market—where products decay within minutes and cannot be stored—behavioural remedies could not replicate the competitive tension created by independent ownership of a cyclotron. The authority viewed the proposed commitments as inherently temporary and insufficient to offset the structural loss of rivalry in a market defined by extreme time sensitivity and capacity constraints.
This outcome should be understood as an exception rather than a general indictment of behavioural solutions. In most sectors, well-designed access obligations, service-level guarantees, and monitoring mechanisms can sustain competition effectively. Here, the decisive factor was the physics of the product: market boundaries shrink to the radius of each cyclotron, and even minor operational frictions can eliminate a rival's viability. In such an environment, structural independence becomes indispensable.
What this means for life sciences deals
- Design remedies with the half-life in mind. Behavioural commitments remain a central tool in merger control and, in most industries, can effectively safeguard competition without resorting to structural divestitures. Access obligations, service-level guarantees, and transparent governance mechanisms often provide flexibility and continuity while avoiding the disruption of asset sales. In this case, however, the CNMC concluded that the extreme temporal constraints of PET radiopharmaceuticals—products that decay rapidly and cannot be stored—created an environment where structural independence was non-negotiable. This outcome should not be read as a general indictment of behavioural remedies. Rather, it illustrates the exceptional nature of markets where physics, not economics alone, dictates competitive dynamics. In most sectors, conduct-based solutions remain a viable and often preferred approach to preserving rivalry while accommodating efficiencies.
- Prior collusion shapes remedy choices. Where post-transaction market structure would consolidate supply in entrenched operators, the risk of coördinated effects is not theoretical. It is amplified when the historical record includes prior collusion or parallel conduct, as in the CNMC's explicit reference to its 2021 antitrust fine. In such contexts, behavioural undertakings are particularly vulnerable to skepticism because they rely on sustained self-restraint in an environment where repeated interaction, capacity transparency, and high stakes create fertile ground for tacit coördination. Agencies are likely to view structural separation as the only credible safeguard against durable oligopoly.
- Public interest is not a detour around competition analysis. While Spain's Council of Ministers retains residual authority to consider public interest factors, this mechanism does not displace the primacy of competition law in merger control. Parties should avoid treating ministerial review as a substitute for a robust remedy package. The referral step may be procedurally foreseeable, but clearance is not automatic. The institutional design of the Spanish system—where the CNMC's substantive assessment remains the baseline—means that public interest considerations operate at the margin, not as a corrective to structural competition concerns.
- Plan for regional remedies in national deals. The CNMC's focus on northeastern Spain illustrates a broader analytical principle: national transactions can hinge on regional market dynamics when physical or logistical constraints fragment supply. This logic extends beyond radiopharmaceuticals to other therapies and diagnostics where immediacy is dictated by physics or biology—such as advanced cell therapies, autologous treatments, or short-lived isotopes. In these settings, merging parties should anticipate the need to ring-fence assets, personnel, and contractual relationships at the regional level. Remedy design must reflect the operational reality that competition is organised around delivery radii, not national averages.
Next steps
The CNMC issued its proposed prohibition decision on 6 October 2025, following an in-depth Phase II investigation. In accordance with Spanish merger control procedure, the case has now been transmitted to the Minister of Economy, Trade and Enterprise, who must determine within 15 days whether to refer it to the Council of Ministers for review on public-interest grounds other than competition. If the Minister opts for referral, the Council will have one month to decide whether to uphold the prohibition or authorise the transaction, with or without conditions. Importantly, this review is confined to general interest considerations—such as public health, security, or technological development—and does not reopen the CNMC's competition analysis.
Parallel to this mechanism, the parties preserve their rights through judicial review. CNMC merger decisions are subject to appeal before the Audiencia Nacional, and an appeal can proceed concurrently with any ministerial or Council process. While interim relief is rarely granted, it may be considered if necessary to prevent irreversible harm.
Finally, operational continuity must remain at the forefront. Hospitals and public purchasers require assurance that patient pathways will not be disrupted regardless of the institutional outcome. This calls for a detailed supply plan, transparent communication of contingency measures, and proactive engagement with regional stakeholders. In markets where minutes matter, reliability is not only a clinical imperative but also a determinant of regulatory credibility.
1 See CNMC Case C/1501/24 – Curium / IRAB.
2 Prohibition decisions in Spanish merger control are exceptionally rare. Since the adoption of the modern regime, outright refusals to clear a concentration have occurred only twice and both under the former TDC: in ENDESA / GAS NATURAL–GAS ARAGÓN (1999), where the authority blocked a transaction that would have created a local monopoly, and in TELEFÓNICA / IBERBANDA (2005), where it recommended prohibiting a deal that would have reinforced Telefónica's dominance in broadband markets—a recommendation ultimately upheld by the government. For purposes of transparency, the author served as lead counsel for the complainant who successfully challenged the Telefónica/ Iberbanda transaction before the TDC.
3 A cyclotron is a type of particle accelerator that uses a combination of a magnetic field and an alternating electric field to speed up charged particles—such as protons or ions—along a spiral path. As the particles gain energy, they spiral outward from the centre of the device until they reach the desired speed and are directed toward a target. Cyclotrons are widely used in medical applications, especially for producing radioisotopes used in PET (positron emission tomography) scans, as well as in nuclear physics research and radiation therapy.
4 See CNMC Case S/0644/18 – RADIOFÁRMACOS, where Spain's two leading PET radiopharmaceutical producers were fined €5.76 million in total.
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