When Clinical Supply Plans Meet Site Reality: Lessons From The Front Line

A Conversation With Sharon Heng, Consultant Ophthalmic Surgeon, Moorfields Eye Hospital

Clinical trial supply planning is essential to keeping studies on track, but even the most carefully developed supply strategies must ultimately work within the realities of clinical site operations. A shipment delay, an inefficient product presentation, or a supply assumption that does not account for site workflows can have consequences far beyond logistics, affecting patient scheduling, treatment continuity, protocol adherence, and overall trial execution.

While clinical supply teams often focus on forecasting, timelines, inventory availability, and distribution planning, the day-to-day impact of supply decisions is experienced most directly by investigators, coordinators, nurses, and patients. Understanding how investigational products move through real clinical environments is critical to building supply strategies that are not only efficient but resilient enough to support the people delivering trials.

In this Q&A, Elizabeth Urbanek, executive editor of Clinical Supply Leader, speaks with Sharon Heng, consultant ophthalmic surgeon at Moorfields Eye Hospital, about the disconnect between clinical supply planning and site realities. Drawing from her experience running high-volume ophthalmic clinical studies, Heng discusses how supply disruptions surface at the site level, how packaging and product design influence workflows, and why closer collaboration between supply teams and investigators during study planning can help protect trial timelines and patient care.

Q1. Where do clinical supply plans most often diverge from the realities of running a trial site?

Planning for supply depends on the manufacturing lead times and delivery windows. It makes sense if it is on paper, but it lacks an understanding of the way an NHS site actually works. At Moorfields, injection clinics are served on a very tight schedule and a late shipment not only slows down a workflow, but it ruins a day's work. I experienced this while conducting research as part of the OZLASE study, which involved a delay in supplying a new batch of data at the end of the study that required new timelines to be negotiated within the study. The assumptions made in a supply plan are greater than the capacity of most sites to absorb.

Q2. What are the early warning signs that a supply issue is beginning to affect trial execution?

The first sign is not in a report. It appears when nurses begin to subtly swap patients to substitute for a shipment that hasn't been received. My experience running high-volume injection clinics at Moorfields is that coordinators start double-booking appointment buffers before they alert to any formal supply concern. Consent discussions also are put on hold because you can't counsel a patient about something you are unsure that you can provide that week. When a supply problem is found in a report of an operational site, the site team has been struggling with it for days already.

Q3. How has product presentation or packaging design affected workflows or protocol adherence at an investigative site?

It's frequently the packaging that causes protocol deviations, not the drug. At Moorfields, in the time I have been using intravitreal introducers, I have seen vial formats that did not take into account the busy clinic setting and had unnecessary preparation steps. This added time adds up quickly on a long list of 20 to 30 patients. If staff have to work around an awkward design and a mistake occurs during administration, the risk increases and is placed straight in your trial data, not elsewhere.

Q4. Beyond temperature integrity, what supply-related issues have had the greatest impact on patient scheduling or treatment continuity?

I have seen the most disruption in timing. As part of the OZLASE study, we had a very tight recruitment period, which forced us to renegotiate timelines at the sites during the course of the study. When patients receive anti-VEGF injections on a regular schedule, the failure to receive an injection at the right time disrupts treatment continuity, which can impact outcomes and patients' confidence in the regimen. Loss of trust in the reliability of treatment schedules is a challenge for patient retention, which is not measured by any supply metric.

Q5. What practical steps could sponsors or clinical supply teams take during study planning to better help site staff?

The repair should be done prior to the beginning of the trial. As an experienced chief investigator on the Wet AMD Burden Study, I can attest to the fact that the supply chain conversation often comes after protocols and site workflows are finalized. Sponsors need to meet with investigators at the study design phase to gain insight into how a clinic operates, not the number of patients it may be able to enroll. If buffering the site is part of the protocol from the start, instead of an afterthought, it would alter the way that sites deal with delays should they occur.

Q6. What would surprise clinical supply planners most about how supply decisions influence day-to-day trial operations?

Truthfully, I believe it would be the silence. Site staff don't pass on supply disruptions as they absorb them, as escalating is the equivalent of saying the trial is in trouble. A supply planner who visited one day at an active injection clinic at Moorfields could see the team working on a tight time schedule with no leeway. They would also watch as one delivery is late and causes several patient appointments and consent discussions to be scheduled for the rest of your afternoon. But the biggest surprise? How rarely any of that surfaces in the data they receive. The site team already solved it before anyone thought to ask.

About The Expert:

Sharon (Ling Zhi) Heng is a multilingual consultant ophthalmic surgeon at Moorfields Eye Hospital, specializing in medical retina diseases. She is the clinical lead for Moorfields Medical Retina Digital Clinics, and the Northwest Diabetic Retinopathy Screening Programme. Heng completed her Ph.D. at UCL after being trained by leaders in refractive surgery and retinal research. In addition to having over 15 years’ experience, presenting over 50 international presentations and holding the role of chief and principal investigator on numerous clinical trials, she has also been appointed as a co-editor on the Royal College of Ophthalmologists’ Inspire Programme, sits on the editorial board of Eye Journal, and advises pharmaceutical companies on treatment biomarkers.