Clinical Trial Kits: Assembly for IMP Sponsors
Key takeaways
Clinical trial kitting is the packaging, labeling and assembly of investigational product and ancillary materials into site-ready or patient-ready kits that match the protocol.
In the US, the immediate package of an investigational new drug must carry the caution statement in 21 CFR 312.6, and labeling must not claim the product is safe or effective for the use under study.
In the EU, Annex VI of Regulation (EU) No 536/2014 lists the label particulars for investigational medicinal products, and each Member State decides the label language.
Packaging and labeling are manufacturing steps, so they fall under GMP, with US phase 1 material handled under FDA's phase 1 CGMP approach and later phases under 21 CFR Part 211.
Kits ship to sites only after required approvals and release, in qualified packaging with temperature records and shipment records that support drug accountability.
Clinical trial kits package an investigational medicinal product (IMP), and everything a site or participant needs to use it, into a unit that matches the study protocol. Clinical trial kit building connects manufacturing, regulatory labeling, blinding, temperature control and distribution in one process. When it works, each site receives the right kit, correctly labeled and in condition. When it fails, dosing schedules slip, sites hold product and the study team spends weeks on corrective action.
This guide is written for sponsors, CROs and clinical supply teams. It explains what clinical trial kitting includes, what goes into a kit, how US and EU IMP labeling rules apply, how kits reach sites and how to choose a kitting partner. It covers the outbound kit itself. For the full supply chain from manufacturer to site, see our guide to clinical supplies management, and for returns see reverse logistics for clinical trial kits.
What is clinical trial kitting?
Clinical trial kitting is the process of packaging, labeling and assembling investigational product and its ancillary materials into kits configured for a specific protocol, site or participant. It is also called clinical trial kit assembly, clinical trial kit production or IMP packaging. The output is a kit that a site can dispense, or that can be delivered to a participant, without further handling beyond what the protocol describes.
Kitting is more than putting items in a box. Applying a label to an investigational product, overlabeling a comparator or assembling blinded configurations are manufacturing operations, so they fall under good manufacturing practice (GMP). In the United States, 21 CFR 210.2(c), published in the eCFR, exempts the production of investigational drugs for phase 1 studies from Part 211, while statutory CGMP still applies. FDA's guidance on CGMP for phase 1 investigational drugs describes that approach. Once the same drug is used in phase 2 or phase 3, or is marketed, material for phase 1 must comply with Part 211 as well.
In the European Union, the GMP rules for IMPs were previously set out in Annex 13 of EudraLex Volume 4. They are now in Commission Delegated Regulation (EU) 2017/1569 and the Commission's detailed guideline on GMP for investigational medicinal products, both listed on the EudraLex Volume 4 page as applicable from the date the Clinical Trials Regulation entered into application. That guideline notes that packaging and labeling of IMPs are more complex and more error-prone than for authorized products, particularly with blinded products, and calls for intensified checks such as reconciliation, line clearance and in-process control.
What goes into a clinical trial kit?
A clinical trial kit contains the investigational product in its labeled immediate and outer packaging, plus the ancillary supplies and documents the protocol requires for dispensing, administration and, where relevant, sample collection and return. The exact contents depend on the protocol, the dosage form and whether the kit goes to a site pharmacy or directly to a participant.
Common components include:
Investigational product, comparator or placebo in labeled immediate packaging, such as blister cards, bottles, vials or prefilled syringes.
Labeled outer packaging, often with a unique kit or treatment number linked to the randomization system.
Ancillary supplies required for administration, such as syringes, needles, diluents or dosing devices, when the sponsor provides them.
Participant materials, such as dosing instructions, diaries or device instructions, where the protocol calls for them.
Sample collection materials, when the kit doubles as a lab kit, with the packaging and labels needed for the return shipment.
A temperature monitoring device for temperature-sensitive product, and tamper-evident seals on the outer packaging.
Every component should match a controlled bill of materials. A missing diluent or the wrong syringe size can stop dosing at a site as surely as a missing vial. For blinded studies, active and placebo kits must look, weigh and feel the same, and secondary packaging should hide any difference in the primary pack.
How are IMP kits labeled?
IMP kits are labeled to the rules of every country where they will be used. In the United States, the immediate package of an investigational new drug must carry a caution statement that reads "Caution: New Drug," followed by the words "Limited by Federal (or United States) law to investigational use," and the label must not be false or misleading or represent the drug as safe or effective for the purposes under investigation, as set out in 21 CFR 312.6. In the European Union, Annex VI of Regulation (EU) No 536/2014 lists the particulars that must appear on the immediate and outer packaging.
For an unauthorized IMP in the EU, the Annex VI general list includes the main contact for product, trial and emergency unblinding information, the substance name and strength, pharmaceutical form, route and quantity, the batch or code number, a trial reference code, the subject or treatment number, directions for use, the words "For clinical trial use only" or similar wording, storage conditions, the period of use in month and year format and, where product goes home with subjects, "Keep out of reach of children." In blinded trials, the substance name appears together with the comparator or placebo name on both versions. Article 69 of the regulation leaves the label language to each Member State, and the product may be labeled in several languages.
IMP labeling drives kit design, so map requirements by country before you finalize artwork. The table below shows the main differences a global study has to reconcile.
Topic | United States | European Union |
|---|---|---|
Main legal source | 21 CFR 312.6 | Regulation (EU) No 536/2014, Articles 66 to 70 and Annex VI |
Required statement | Caution statement limiting the drug to investigational use | "For clinical trial use only" or similar wording |
Detailed particulars | Not listed item by item in 312.6, defined by the sponsor's labeling and GMP controls | Itemized list in Annex VI, with rules for immediate, outer and small packaging |
Language | Not addressed in 312.6, so confirm language needs for US sites with regulatory affairs | Determined by each Member State concerned |
Authorized products used as IMP | Depends on the IND and how the product is supplied | Labeled under Article 67, either per Article 66 or per the marketing authorization rules with added trial particulars |
The Clinical Trials Regulation entered into application on 31 January 2022, according to the European Medicines Agency. New trial applications have had to use the Clinical Trials Information System since 31 January 2023, and the transition period for trials approved under the old directive ended on 31 January 2025. Labeling questions for a specific country should be confirmed with your regulatory affairs team, because national practice on language and booklet labels can differ.
Clinical trial kit production at scale
Clinical trial kit production usually runs as a series of campaigns rather than one large build. The first campaign covers initial site supply, and later ones follow enrollment, expiry dating and protocol amendments. Building smaller campaigns reduces the risk of labeling a large quantity that later needs relabeling because of an expiry extension or a new country.
Several controls keep scaled production reliable. Label text and artwork go through version control and approval before printing. Each packaging run uses line clearance so that no labels or product from a previous run remain. Label reconciliation compares labels issued, used, destroyed and returned, and any discrepancy is investigated before release. For blinded studies, randomization lists and kit numbers are generated and applied under controls that keep the blind intact for site staff.
Release is a separate step from assembly. In the EU, a qualified person certifies each batch before it is released for the trial. In the US, release follows the sponsor's quality system and, from phase 2 onward, Part 211 requirements. Plan release time into the supply schedule, because a finished kit cannot ship until it is released.
Temperature control in the kit
Many investigational products require 2 to 8 °C, frozen or controlled room temperature storage, and the kit has to protect that range from packaging through receipt at the site. That means a packaging configuration qualified for the lane and season, a calibrated monitoring device in the shipper and a clear instruction for the site on how to read and report the record on arrival.
Packaging qualification and lane validation are covered in our article on cold chain logistics for clinical trials. The background standards are summarized in our glossary entry on Good Distribution Practice.
How are clinical trial kits shipped to sites?
Clinical trial kits are shipped to sites only after the trial has the required approvals and the kits have been released, using packaging qualified for the product's temperature range and route, with a monitoring device, shipment records and handover documentation. Shipments usually move from a central or regional depot on a resupply schedule linked to enrollment, often triggered by an interactive response system.
ICH E6(R3), adopted by ICH in January 2025 and issued by FDA as final guidance in September 2025, states in its guideline text that investigational product should be supplied after the required ethics committee and regulatory approvals. It also allows product to be shipped to a participant's location or supplied at a location closer to the participant. For US studies, 21 CFR 312.57 requires sponsors to keep records of each shipment, including, as appropriate, the investigator's name, the date, the quantity and the batch or code mark.
A typical kit preparation and shipment for clinical trials follows this order:
Confirm the site is activated and approved to receive product and that the order matches the resupply request.
Pick released kits by kit number, checking expiry against the planned use window.
Condition coolant and pack the shipper to its qualified configuration, then start the temperature monitor.
Prepare shipment documents, including the packing list with kit numbers and lots, and any import documents for international sites.
Book a service whose transit time fits the packaging duration and the site's receiving hours.
Track the IMP shipment, and confirm receipt, temperature record and kit numbers at the site so accountability starts accurately.
International IMP shipment adds import permits, customs clearance and sometimes a local importer of record. Ask the destination's regulatory and customs contacts to confirm requirements for each country before the first shipment. Direct-to-participant supply adds privacy and scheduling steps, which our direct-to-patient logistics guide covers. Throughout, a clear chain of custody protocol shows who held the kit at each handover.
Design the kit for its return
Kits rarely travel one way. Sites return unused product, expired kits and reusable shippers, and the outbound design either helps or hinders that flow. Include return instructions and, where used, return labels or packaging in the outbound kit, and make sure kit numbers are easy to scan at return. The details of returns, reconciliation and destruction belong in our article on reverse logistics for clinical trial kits.
How do sponsors choose a clinical trial kitting service?
Sponsors choose a clinical trial kitting service by confirming that the provider holds the right manufacturing authorizations for the work, runs packaging and labeling under GMP, has experience with the study's dosage form, blinding design and temperature range, and can connect assembly to release, storage and distribution without gaps. Audit history, quality agreements and communication matter as much as price.
When you compare clinical trial kitting services, ask each provider:
Which licenses or authorizations cover labeling and packaging of investigational product in each relevant region, and which inspections have they had? Ask for evidence rather than a statement, because these vary by country and by activity.
How do they manage label text, translations, printing, reconciliation and line clearance, and who approves the final artwork? Ask to see a recent label reconciliation record with sensitive details removed.
What blinding experience do they have, and how do they keep kit configurations identical across arms?
Where are storage and depot locations, what temperature ranges can they hold, and how is release handled before shipment?
How will kit numbers, lots and expiry data flow into your interactive response system and shipment records, so that site accountability starts with accurate data?
Who handles the transport and how is each lane qualified? Many sponsors use one partner for assembly and another for distribution, which works well when handover, documentation and responsibility are written into the quality agreement.
Mercury focuses on the transport side of this chain, moving released kits from depots to sites and participants under temperature control. Our clinical trial logistics team works with sponsors and CROs on outbound kit distribution, international documentation and specialty cold chain shipping.
