SOP: Randomisation, Blinding, and Emergency Code-Break Control

This is a ready-to-use SOP for the controls that protect the blind on the manufacturing and supply side of a clinical trial: securing the randomisation code, making test, comparator, and placebo indistinguishable, generating comparability data for re-packaged comparators, and controlling emergency code-break. Quality owns the integrity of the blind on the supply side. Replace every <<FILL: ...>> placeholder and route it through your document control. A filled specimen follows. Verify each cited regulation against the current source before you rely on it.

Document control header

1. Purpose

This procedure defines how <<FILL: COMPANY NAME>> protects the blind of a blinded clinical trial on the supply side: how the randomisation code is generated and secured, how products are made indistinguishable, how re-packaged comparators are shown not to compromise the trial, and how a single subject can be unblinded in a genuine emergency without compromising the rest of the trial.

2. Scope

Applies to blinded (single- or double-blind) trials in the header. It covers the supply-side controls; the clinical conduct of unblinding and pharmacovigilance follow <<FILL: SOP-ID for clinical unblinding / PV>>.

3. Responsibilities

4. Definitions

• Randomisation code: the assignment of treatment to subject or kit numbers.
• Blinding: making test, comparator, and placebo indistinguishable to those who must remain blinded.
• Code-break (emergency unblinding): a controlled reveal of a single subject’s treatment in a medical emergency, without unblinding the rest of the trial.
• Over-encapsulation: enclosing a tablet or capsule (active or placebo) in an identical opaque capsule to make products indistinguishable.

5. Procedure

5.1 Randomisation code security

1. The code is generated under control by an independent party (statistician or IRT vendor).
2. It is held securely and separated from anyone who must remain blinded (packaging, QC, and the QP for the blinded elements).
3. Access is restricted, logged, and auditable. People who manufacture, label, or certify the IMP cannot deduce assignments where blinding requires it.

5.2 Product blinding

1. Design the packaging so test, comparator, and placebo are indistinguishable in appearance, smell, taste, weight, and packaging to blinded people (for example over-encapsulation of an active tablet and a matching placebo into identical opaque capsules).
2. Perform a documented blinding assessment, ideally a blinded check, confirming indistinguishability including weight.
3. Record the assessment and its acceptance.

5.3 Comparability for re-packaged comparators

1. Where a comparator is over-encapsulated or re-packaged for blinding, generate comparability data showing the re-packaging does not adversely affect the product (for example dissolution/bioavailability) in a way that affects the trial.
2. Assign an expiry consistent with data on the re-packaged form; do not exceed the original justified shelf life without data. See comparators sourcing.

5.4 Emergency code-break control

1. Provide code-break capability at site (sealed envelopes or an electronic system), designed to reveal only the single subject’s assignment.
2. Restrict use to genuine medical emergencies.
3. Log every code-break event: subject, date/time, who, and justification.
4. Trigger the pharmacovigilance assessment for the event.
5. Confirm the rest of the trial remains blinded after the event.

5.5 QP confirmation

At certification the QP confirms blinding integrity (indistinguishability, code security, comparability for re-packaged comparators) without needing the actual assignments.

6. Acceptance criteria

• The randomisation code is generated under control and held separate from blinded staff, with access logged.
• Test, comparator, and placebo are indistinguishable, confirmed by a documented blinded assessment.
• Re-packaged comparators have comparability data and an expiry supported by data.
• Code-break reveals a single subject only, is logged, and triggers PV; the rest of the trial stays blinded.
• Code-break is used for genuine emergencies, not routinely.

7. Records generated

Randomisation code-access log; blinding assessment record; comparability data reference; code-break event log; PV assessment references.

8. Common findings this SOP prevents

• Test and comparator distinguishable by weight, capsule fill, or packaging detail.
• Randomisation code accessible to packaging or QC staff who should be blinded.
• Code-break events not logged, or used routinely rather than for genuine emergencies.
• No comparability data for an over-encapsulated or re-packaged comparator.
• Re-packaged comparator expiry exceeding what the data on the re-packaged form supports.

9. References

EudraLex Volume 4 Annex 13 (Manufacture of Investigational Medicinal Products), blinding and randomisation code expectations. Regulation (EU) No 536/2014 (Clinical Trials Regulation). ICH E6 Good Clinical Practice for the clinical conduct of unblinding. Related reading: GMP for investigational medicinal products, comparability and potency assays.

Confirm the current version and clause numbers of each reference before issue.

10. Revision history

11. Approvals

Filled specimen

The following shows a completed blinding assessment and code-break log entry for an example over-encapsulation trial, so you can see how the controls read. The values are illustrative.

In this example the over-encapsulation made active and placebo indistinguishable by appearance and weight, the re-packaged comparator had dissolution comparability data supporting its expiry, and the one code-break was logged with time, authoriser, and PV linkage while the rest of the trial stayed blinded. A common failure is over-encapsulating without a weight check (capsules that differ by fill weight break the blind) or leaving a code-break unlogged, both of which this record forces into the open.

How to adapt this SOP

1. Set your document number, owner, and blinded trials in scope in the header.
2. Match the blinding technique to your products (over-encapsulation, matched placebo, identical kits).
3. Require a documented blinded assessment including a weight check.
4. Wire the code-break log to your pharmacovigilance process.
5. Confirm every regulation in section 9 against the current published version before issue.