Comparator medicines in clinical trials: a sourcing guide

Every comparative clinical trial needs a benchmark. The comparator medicine — the already authorised product against which the investigational treatment is measured — looks, at first glance, like the easy part of supply: the product exists, it is in pharmacies, you buy it. In practice, comparator sourcing is one of the most delicate logistics operations in a trial, and mistakes are paid for in protocol delays and questioned data.

What a comparator medicine is

The comparator is an authorised medicine used in a clinical trial as the comparison arm for the investigational product. It may be the standard of care for the studied condition (active comparator) or the baseline against which superiority or non-inferiority of the new treatment is assessed. Within trial documentation it falls under investigational products — meaning its quality, traceability and handling requirements are comparable to those of the new product, not those of an ordinary commercial good.

Why sourcing is harder than it looks

Five constraints come up in almost every project:

• Actual market availability. The quantities a trial needs can exceed what distributors have immediately available, especially for high-demand products or those periodically in shortage.
• Batch consistency. Many protocols require a single batch for the whole study, or a limited number of batches — hard to achieve without access to large sources.
• Minimum shelf life. An 18-month study needs products with shelf life to match; a short-dated comparator means resupply, relabelling and additional cost.
• Cold chain. Biologicals and many injectable forms demand an unbroken 2–8 °C chain from supplier to trial depot — with recorded proof of every stage.
• Documentation. Auditors and authorities require a complete chain of custody: where the product came from, which warehouses it passed through, under what conditions it was kept. Without those documents the product is, in practice, unusable in the trial.

Central or local sourcing?

Central sourcing — one partner procuring the full quantity and distributing it to depots or sites — delivers consistent batches, uniform documentation and a single point of accountability. Local, country-by-country sourcing can be useful where regulation requires a locally authorised product or where cross-border logistics is impractical. Many studies end up with a mixed model; what matters is that every supply route is documented to the same standard.

The European Union market brings a concrete advantage here: for centrally authorised products, composition is identical across member states, which opens the door to procuring from markets with better availability or lower cost — Romania frequently being one of them.

What a sound sourcing process looks like

1. Product specification: name, strength, pharmaceutical form, pack size, total quantity, batch and shelf-life requirements.
2. Source verification: licensed suppliers only, with confirmation of real availability and delivery terms — not catalogue promises.
3. Quotation with realistic lead times: including the fallback scenario if the targeted batch sells out before contracting.
4. Documented procurement: invoices and provenance documents reconstructing the chain of custody from the source.
5. Incoming control: lot number, expiry, integrity, conformity with the specification.
6. Monitored delivery: qualified packaging, recorded temperature, handover with the complete history.

The questions worth asking your supplier

Before choosing a sourcing partner, ask for concrete answers to four questions: Which sources does the product come from, and how do you evidence the chain of custody? Can you guarantee the single batch and minimum shelf life the protocol requires? How is temperature monitored en route, and who receives the data? What happens if the product becomes unavailable mid-study? A serious partner has documented answers to all four — and gives them to you in writing.

For details about our sourcing service, see the dedicated comparator medicines page or send us the specifications of your trial.