Blinding, Labeling, Storage and Destruction Procedures

Part of Good Clinical Practice (GCP) — ICH E6(R3): Investigational Product (IP) Management.

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Why this matters

Blinding is the fragile part of a clinical trial. It can survive a thousand visits, then be destroyed by one laboratory report sent to the wrong inbox. Once a site is unblinded, the assessments made there are no longer unbiased. Unintentional unblinding is a common compliance issue, and it is almost always preventable.

Principle 11: the six sub-points

International Council for Harmonisation (ICH) guideline E6(R3) for Good Clinical Practice (GCP) gives investigational product a Principle of its own. Principle 11 reads:

"Investigational products used in a clinical trial should be manufactured in accordance with applicable Good Manufacturing Practice (GMP) standards and be managed in accordance with the product specifications and the trial protocol."

Its six sub-points cover the product life cycle.

• 11.1 — manufactured in accordance with applicable GMP standards.
• 11.2 — measures in place so the product provided to participants retains its quality.
• 11.3 — used in accordance with the protocol and relevant trial documents.
• 11.4 — manufacturing, handling and labeling aligned with treatment assignment and maintaining blinding, where applicable.
• 11.5 — labeling follows applicable regulatory requirements.
• 11.6 — appropriate processes for handling, shipping, storage, dispensing, returning and destroying or alternatively disposing of the product.

Note 11.5. The guideline does not specify what must appear on a label. It defers to applicable regulatory requirements, which differ by country.

Randomization procedures and unblinding: the investigator's duty

The E6(R3) Glossary defines randomization as "The process of deliberately including an element of chance when assigning participants to groups that receive different treatments in order to reduce bias." Randomization creates the comparison. Blinding protects it.

Section 2.11 is short and should be read in full. The investigator should follow the trial's randomization procedures, if any. In an investigator-blinded trial, the code is broken only in accordance with the protocol.

For emergencies, section 2.11 says the investigator "should be prepared and capable from the start of the trial to perform unblinding without undue delay and hindrance." That capability must exist from day one, not be arranged when a participant deteriorates at night.

Section 2.11 also requires the investigator to "promptly document and explain to the sponsor any premature unblinding" of the product. It names three examples: accidental unblinding, emergency unblinding to protect a participant, and unblinding due to a serious adverse event.

Section 4.1.4 adds: "Any planned or unplanned unblinding, including inadvertent or emergency unblinding, should be documented. Any unplanned unblinding should be assessed for its impact on the trial results." The potential for unblinding should also be part of the risk assessment of a blinded trial.

What the sponsor must put in place

Section 3.15.2(a) requires the sponsor to ensure the product is manufactured under any applicable GMP and "is coded and labeled in a manner that protects the blinding, if applicable." Section 3.15.2(d) lists three mechanisms the sponsor must implement in blinded trials.

• 3.15.2(d)(i) — a process to blind the relevant individuals, including sponsor staff, the participant, the investigator and site staff as appropriate, "and a process to prevent and detect inappropriate unblinding."
• 3.15.2(d)(ii) — a mechanism letting the investigator rapidly identify the product in a medical emergency, "while protecting the identity of the treatment assignment of the other trial participants."
• 3.15.2(d)(iii) — a mechanism that protects the blinding where a participant's assignment is unblinded for safety reporting to regulatory authorities or the institutional review board or independent ethics committee (IRB/IEC).

Sub-point (i) contains a word sites often miss: detect. Preventing unblinding is not enough. There must also be a process that finds out when it has happened anyway.

Appendix C names two related essential records: "Emergency decoding procedures for blinded trials" and "Master randomization list." Both should generally be in place before the trial starts.

Storage conditions

Section 3.15.2(b) puts the specification duty on the sponsor. The sponsor determines acceptable storage temperatures, conditions such as protection from light, shelf life, reconstitution fluids and administration devices. It then "should inform all involved parties (e.g., monitors, investigators, pharmacists, storage managers) of these determinations."

Section 2.10.5 requires the site to store the product as the sponsor specifies. Common site conditions:

• Refrigerators — 2 to 8 degrees Celsius
• Freezers — minus 20 degrees Celsius, or minus 70 degrees Celsius depending on the product
• Room temperature — 15 to 25 degrees Celsius, as specified

These are typical operational ranges, not numbers set by E6(R3). Follow the sponsor's written specification. Good practice adds a locked cabinet with restricted access, calibrated data loggers and excursion alarms.

Temperature excursions

When a storage or transit temperature moves outside the specified range:

1. Quarantine the affected product immediately, separated and labeled as not for dispensing.
2. Document the incident, with dates, times, temperatures reached and duration.
3. Inform the sponsor without delay.
4. Wait for the sponsor or manufacturer evaluation. The site does not decide whether the product is still usable.
5. Follow the documented disposition — return to use, continued quarantine, or destruction.

Never dispense quarantined product. Appendix C names "Documentation of investigational product storage conditions, including during shipment" as an essential record.

Return and destruction

Principle 11.6 requires processes for returning and destroying or alternatively disposing of the product. Section 2.10.4 requires records of the return to the sponsor and of destruction or alternative disposition. Section 3.15.3(c) requires the sponsor to maintain a retrieval process, for example for a recall, and a process for disposing of unused product.

The site rule is simple. No investigational product is destroyed without documented sponsor authorization, and every destruction is recorded.

In practice

A double-blind trial is running at Dr. Sarah's site. At 23:40 a participant arrives at the emergency department with severe hypotension. The treating physician needs to know whether the participant is on active drug.

The on-call coordinator, Ana, follows the emergency unblinding procedure required by section 3.15.2(d)(ii). She uses the interactive response system to unblind that single participant. No other assignment is exposed.

Ana then does four things. She documents the unblinding, with date, time, reason and who was informed. She notifies the sponsor promptly, as section 2.11 requires. She records the serious adverse event through the safety reporting route. She arranges for that participant's blinded efficacy assessments to be done by a colleague who still does not know the assignment.

Contrast a second case. A laboratory report showing a pharmacokinetic concentration is emailed to the blinded coordinator in error. Nobody planned it. It is still unblinding. Under section 4.1.4 it must be documented and assessed for its impact on the trial results. Under section 3.15.2(d)(i), the sponsor's process should have detected it.

Key takeaways

• Principle 11.4 requires manufacturing, handling and labeling to align with treatment assignment and maintain blinding; Principle 11.5 defers labeling content to applicable regulatory requirements.
• Section 2.11 requires the investigator to break the randomization code only per the protocol, and to be capable of emergency unblinding without undue delay from the start of the trial.
• Section 2.11 requires any premature unblinding to be promptly documented and explained to the sponsor.
• Section 3.15.2(d)(i) requires a process both to prevent and to detect inappropriate unblinding; detection is a separate duty.
• Section 3.15.2(d)(ii) requires emergency unblinding of one participant to protect the treatment assignments of all others.
• Section 3.15.2(b) makes the sponsor responsible for determining storage temperatures, conditions and shelf life, and for informing the site.
• Product affected by a temperature excursion is quarantined, and its fate is decided by the sponsor, never by the site.