Case Study: avoiding an emergency unblinding


In an emergency medical situation, the treating physician usually wants to know what study medication the patient is receiving, and many of the calls that ESMS receive start with a request for unblinding.

However, equipped with information from the protocol and Investigator’s Brochure, it is often possible for ESMS to prevent unnecessary unblinding while providing the physician with the information they need to treat the patient safely.

In the following example, we were able to avoid unblinding and assist the physician in treating a patient following a cardiac arrest.


ESMS received a call from an intensive treatment unit physician about a patient who had experienced a cardiac arrest 12 hours after their second cycle of study treatment.

The patient was found by their relative in the early hours of the previous morning with irregular breathing. An ambulance was called and the patient was found to be in asystole. The patient was admitted to the intensive treatment unit at the hospital and was on a ventilator.

It was at this point that the patient’s physician called ESMS with a request to unblind the patient.

The patient was participating in a randomised, double-blind, phase 3 trial investigating treatment of lymphoma. The patient had been receiving their study medication in addition to R-CHOP chemotherapy, as well as taking antiemetics. They last took their study medication two days ago along with their second cycle of chemotherapy.


The call from the ITU physician was answered within 20 seconds and the ESMS Physician and Information Scientist (IS) reviewed the study protocol and Investigator’s Brochure, and discussed the following information with the physician:

  • Cardiac arrest was not listed as an Expected Serious Adverse Event for the IMP.
  • Cardiac disorders including arrhythmia had been reported previously with the patient’s chemotherapy regime.
  • Study drug should be withheld for any unmanageable, potentially study drug-related toxicity.
  • All concomitant medications were permitted except for CYP3A4 inhibitors.
  • There was the potential for interaction between the study drug and antiplatelet agents and anticoagulants, with guidance available in the protocol.


The physician commented that they suspected the event was more likely due to the chemotherapy than the IMP. They confirmed that the patient has not received any CYP3A4 inhibitors, antiplatelet agents or anticoagulants.

The ESMS IS advised the physician that it would be possible to unblind the patient if they felt that their medical management was dependent upon knowing the treatment allocation. The physician confirmed that, based on the information provided, there was not a need to unblind at the current time, and they would contact ESMS again if required. The SAE was fully captured and reported to the Sponsor Pharmacovigilance within 24 hours.

Outcome and benefits for the client

  • Avoided unblinding the patient while ensuring the treating physician received information required to treat the patient safely.

  • Ability to rapidly perform emergency unblinding should the physician decide this is required for safe management of the patient.

  • Immediate access to consultant physicians if a further clinical discussion is required.

  • The highly experienced team at ESMS are trained to recognise adverse events and ensure all SAEs are reported to PV within agreed timeframes.

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