Depot-to-Site Supply Strategy: 10 Key Considerations for Clinical Success

By Rashi Gupta

Depot-to-site clinical supply strategy ensures that the investigational product (IP) is available at the right site, in the right quantity, at the right time. Yet deciding when to ship to sites and how much to send is far from straightforward. Too much inventory risks expiry and waste; too little risks missed dosing, enrollment setbacks, and trial delays. The challenge grows in multicohort, multisite, and multicountry studies. Strategies must be designed at trial outset and reassessed regularly as timelines shift, manufacturing conditions change, and supply availability evolves. Clinical supply managers also face factors beyond their control from protocol amendments and site activation delays to shelf-life limitations, logistics risks, and manufacturing disruptions. To manage these complexities, they must decide when to push inventory to sites versus hold it at depots, and when to use predictive IRT logic or static min/max settings. The following 10 factors provide a framework for making those decisions.

10 Key Considerations for Selecting Clinical Depot-to-Site Supply Strategies

1. Patient Enrollment Rate – High or unpredictable enrollment can quickly deplete inventory, increasing the risk of stockouts and costly emergency shipments. Regularly track enrollment trends via IRT to identify when resupply thresholds need adjustment.Recommendation: Maintain higher buffers at sites with rapid or variable enrollment and lower levels for sites with slow or steady enrollment. You could start with higher stock and gradually reduce the inventory level as enrollment rate stabilizes. Use predictive IRT when enrollment varies widely across sites; use of static IRT is more suitable when enrollment rates are stable across sites.
2. Enrollment Lead Time – The time from screening to randomization affects how soon inventory is needed after screening begins. Sites that randomize patients quickly (e.g. same day, next day) require inventory in advance, while slower sites can be stocked later. Collaborate with Clinical Operations to stay current on the lead times by country/site.Recommendation: Keep higher initial stock and inventory buffers at fast-randomizing sites; use lower stock at slower-enrolling sites. Hybrid IRT works well: start with static seeding and fixed min/max buffers for near-term enrollments (e.g., within two weeks), then use predictive logic for ongoing visits.
3. Dosing Regimen Complexity – Weight-based, titrated, or multivisit dosing regimens require accurate forecasting of kit types and quantities. Errors in kit mix can lead to protocol deviations or urgent resupply. Multitreatment studies also require higher inventory to support randomization.Recommendation: Maintain higher stock quantities for complex or variable dosing; lower for uniform or fixed dosing regimens. Use predictive IRT for weight-based, titrated, or multiarm trials with variable needs; use static IRT for single-dose fixed regimens. Additionally, when weight-based enrollment is unknown, plan to the highest dose until actual data is available.
4. Shipment Lead Time – Lead times from shipment order to IP receipt can vary significantly by country and site. Long or unpredictable lead times may disrupt dosing schedules and enrollment momentum. Tracking real-world shipment lead times, which may differ from vendor estimates, improves planning accuracy.Recommendation: Maintain higher safety stock either in absolute terms or through extended weeks of supply. Trigger earlier resupply for sites with long or variable lead times (e.g., 5-10+ days). For sites with short consistent lead times, lower inventory may suffice. Use predictive IRT to ensure timely replenishment under uncertain lead times. Use static IRT where lead times are stable and reliable.
5. Product Availability – Scarce supply or delayed batch release limits flexibility. Retaining stock at depots and prioritizing shipment to active sites helps avoid stockouts before new batches are released and available.Recommendation: Maintain lower inventory when the supply is tight, increasing only for high priority or fast enrolling sites. Use predictive or hybrid IRT to allocate limited inventory based on real-time demand. Use low min/max buffers and consider manual allocations until supply stabilizes.
6. Shelf Life & Expiry Risk – Short shelf life increases the risk of IP expiry at sites, leading to waste and potential shortages. Retaining stock at depots also simplifies relabeling if expiry is extended.Recommendation: Keep lower site inventory for IP with short shelf life, increasing only when supported by stability data or justified by resupply delays. Use predictive IRT when shelf life is short as it aligns shipments to actual needs and expiry. Use static IRT when shelf life is long and demand is predictable.
7. Site Storage Constraints – Limited space or cold chain storage capacity affects how much IP sites can hold. Overstocking risks temperature excursions, noncompliance, and waste; understocking, especially in high enrolling sites, can risk missed dosing.Recommendation: Use lower inventory at sites with storage limitations and increase only if capacity allows. For high enrolling sites with constraints, plan smaller, more frequent shipments. Predictive IRT supports frequent, smaller resupply; static IRT needs to be enforced with strict max limits. When projected demand exceeds capacity, use manual shipments to bridge gaps without breaching storage limit.
8. Labeling Format & Flexibility – Global labels allow for pooled inventory and flexible redistribution across depots and sites, which is especially beneficial in multicountry or staggered-start trials. Local labels restrict redistribution and increase planning complexity.Recommendation: Maintain higher stock for local label sites; lower stock for global label sites with centralized resupply. Predictive IRT works best when global labels enable central inventory and flexible demand-based shipping. Static IRT fits country-specific labels with fixed pools.
9. Initial Seeding at Site Activation – Shipping too much IP at site activation can result in expiry and misallocation if enrollment is slow. Sending too little may delay first patient dosing if enrollment starts quickly. Close coordination with Clinical Operations is essential to understand activation-to-first-patient timelines and enrollment lead times for each site.Recommendation: Seed sites conservatively at activation (e.g., enough for 1-2 patient visits) unless rapid enrollment is expected. Increase inventory as patients are screened and enrolled, scaling based on actual demand. For limited supply or long enrollment lead times, consider shipping IP only after enrolling the first patient. Use static IRT for initial seeding and transition to predictive IRT for ongoing resupply.
10. Shipping Frequency & Cost – Frequent shipments raise logistics costs and site workload; infrequent shipments risk overstocking or missed dosing. Carefully balance shipment frequency with the risk of stockouts and waste, aiming to avoid costly expedited shipments.Recommendation: Keep lower stock when shipment cadence is cost efficient and controlled; increase stock only if it reduces overall logistics burden. Static IRT suits cost sensitive trials with stable demand. Predictive IRT is better when shipment batches optimally balance cost and supply continuity.

In summary, high site stock is appropriate when shipment lead times are long, patient demand is high or variable, shelf life is long, and supply is secure. Low site stock is suitable when shipment lead times are short, enrollment is slow, supply is limited, or shelf life is short. Predictive IRT works best with known patient visit patterns, enabling dynamic resupply based on projected demand. Static IRT is preferable when demand is steady, and trial complexity is low.

While these 10 considerations for depot-to-site supply strategy are dynamic and often overlap, applying the recommendations can balance responsiveness and efficiency. Ultimately, this will ensure IP reaches patients on time with minimal waste and cost.

Key Takeaways

• Balance is critical. Overstocking drives waste and higher costs, while understocking risks dosing and trial timelines. An effective site supply strategy manages both proactively.
• IRT configuration is a strategic lever. Choose predictive, static, or hybrid IRT configuration based on trial dynamics, product characteristics, and logistic realities to ensure both agility and control.
• Strategies must evolve. Reassess enrollment patterns, product availability, and operational constraints regularly to adjust site supply strategies.

For support determining, implementing, or managing your clinical site supply strategy, contact our team of experts today at info@convergeconsulting.com.