In an adaptive oncology trial, the RTSM must do four things that a conventional randomization system is not required to do: enforce configurable cohort and dose assignment rules in real time, support mid-study arm management updates without a full system rebuild, maintain a complete audit trail documenting which rules applied to which patients at every point in the trial, and integrate supply management with adaptive randomization logic so that arm expansions and arm closures are reflected in resupply triggers automatically. A system set up for a static design and patched when adaptations occur creates manual workarounds and documentation gaps that cannot be remediated at closeout.
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Why Is the RTSM Different in an Adaptive Trial?
The RTSM system in an adaptive oncology trial carries responsibilities that do not exist in a conventional fixed design. It is not a randomization system that happens to be used in an adaptive trial — it must be architected for adaptivity from the start.
Sponsors evaluating RTSM providers for adaptive programs should understand specifically what the system must be capable of, and how to verify that capability before the protocol is locked.
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What Are the Core Adaptive RTSM Requirements?
Can the system enforce cohort and dose assignment rules as specified in the protocol?
The system must be able to enforce cohort size limits, dose escalation criteria, and de-escalation rules as they are specified in the protocol — not approximated in workarounds. For dose escalation programs specifically, this means the RTSM enforces which patients can be assigned to which dose level at any given point in the escalation scheme, with real-time checks at the point of randomization.
Can the system be updated mid-study without a full rebuild?
When an interim analysis triggers an arm drop, cohort expansion, or eligibility change, the RTSM must be updatable without a full system rebuild. This requires a validation and user acceptance testing (UAT) process that can be completed quickly. The ROBIN project specifically recommends preparing update documentation in advance and ensuring testing resources are available at short notice when interim decisions are imminent (BMC Medicine, 2025).
Does the system maintain a complete adaptation audit trail?
Every change to the RTSM configuration — including which rules applied to which patients at what point in the trial — must be captured in an audit trail that can be produced for regulatory review. This is not just a GCP requirement. It is what allows a sponsor to demonstrate to a regulatory authority that the adaptive scheme was implemented as pre-specified.
Is supply management integrated with adaptive randomization logic?
In adaptive oncology trials where cohort changes affect drug supply allocation, the RTSM must integrate supply management with the adaptive randomization logic. An arm expansion not reflected in depot resupply triggers leaves a site without drug when they need it. An arm drop not reflected in supply allocation wastes investigational product and creates accountability questions.
Kyle Hanson, Director of Clinical Operations, Sitero:
“The most damaging scenario is a randomization rules mismatch during cohort transition. This happens when the RTSM is updated to reflect a protocol amendment — a new stratum, a closed arm, a modified allocation ratio — but the go-live date for the system change isn’t tightly synchronized with the protocol effective date and site notification. You get a window, sometimes just forty-eight hours, where sites are operating under the old mental model and the system is running under new rules, or vice versa. Patients get randomized to arms that should be closed, or blocked from arms that should be open. Prevention comes down to three things: formal RTSM change control with a UAT gate before any cohort transition goes live; a site communication cascade that goes out before the system change, not after; and a 24-hour randomization hold at the transition point if the complexity warrants it.”
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Adaptive vs. Conventional RTSM Capability Requirements
| RTSM Capability | Conventional Trial Requirement | Adaptive Trial Requirement |
|---|---|---|
| Randomization scheme | Static, pre-specified | Dynamic; cohort rules and dose levels configurable and updatable |
| Mid-study system updates | Rare; major amendments only | Expected; must support rapid UAT and validation for arm changes |
| Audit trail scope | Patient assignments and dispensing | All configuration changes, with timestamps relative to interim decisions |
| Supply management | Depot resupply based on enrollment rate | Arm-specific resupply logic with expansion/closure scenario modeling |
| Adaptation decision documentation | Not applicable | Pre-prepared update documents for each plausible adaptation scenario |
| Testing resources | Standard validation timeline | On-call UAT resources when interim window is active |
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5 Questions to Ask Your RTSM Provider Before Protocol Lock
- Can you demonstrate a prior adaptive trial configuration — specifically one with dose escalation and cohort modification rules?
- What is your typical timeline for implementing a RTSM update following an interim analysis decision?
- What does your UAT process look like for mid-study RTSM changes, and how long does it take?
- How is supply management integrated with adaptive randomization in your system — specifically, how does an arm closure trigger supply reallocation?
- What does the audit trail look like for a cohort modification — specifically, how is the change documented relative to the interim analysis decision?
A provider that answers these questions with documented processes and prior examples is operating with genuine adaptive trial capability. A provider that answers with general assurances about system flexibility is not.
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What Does Integrated RTSM Mean in Practice?
Sitero’s RTSM module, part of the Mentor eClinical platform, supports adaptive scheme configuration including dose escalation, cohort expansion, and arm dropping, with full audit trail documentation and integrated supply management (Sitero oncology program data). The system is part of an integrated eClinical platform — meaning RTSM updates are coordinated with EDC, eConsent, and reporting without separate system changes across vendors.
Three operational advantages of integrated RTSM in adaptive programs:
- RTSM adaptation changes propagate to EDC and reporting without manual cross-system reconciliation
- Supply management data is continuously reconciled with EDC treatment records
- Audit trail is unified across RTSM, EDC, and eConsent — regulatory submission-ready without assembly from multiple vendor systems
Related Resources
Adaptive Oncology Trial Design
Oncology CRO Services & Technology
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Frequently Asked Questions
Q: Can an existing RTSM system used in a conventional trial be repurposed for an adaptive design?
Technically possible in some systems, but the architectural difference matters. An RTSM built for a static design typically requires significant custom development to support mid-study arm management, scenario-based supply logic, and the adaptation audit trail. The development and validation timeline for this work is longer than setting up a purpose-built adaptive system from the start — and the result carries higher documentation risk.
Q: How long does a RTSM mid-study update typically take to validate and deploy?
This depends heavily on the system architecture and the scope of the change. A purpose-built adaptive RTSM with pre-prepared update documentation can complete UAT for a cohort expansion in days. A conventional system requiring custom development for each adaptation may take weeks — which directly delays the implementation of a positive interim analysis decision.
Q: What regulatory guidance covers RTSM requirements for adaptive trials?
FDA guidance on adaptive trial designs (2019) and EMA reflection papers on adaptive designs address the requirement for pre-specified adaptive schemes and the documentation of implementation. Neither specifies RTSM architecture, but both require that sponsors demonstrate the adaptive scheme was implemented as pre-specified — which is only achievable with a complete, timestamped RTSM audit trail.
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Planning an oncology trial with adaptive randomization requirements?
Sitero has supported 200+ oncology studies across 67+ countries. Talk to an oncology trial expert to discuss your protocol.
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References
- Sitero. Oncology Program Operational Data. Internal dataset. 200+ oncology studies across 67+ countries. sitero.com/oncology/
- Hanson K. Director of Clinical Operations, Sitero. Expert interview conducted for this article. April 2026.
- Mossop H, Walmsley Z, Wilson N, et al. Practical guidance for conducting high-quality and rapid interim analyses in adaptive clinical trials (ROBIN project). BMC Medicine. 2025;23. doi:10.1186/s12916-025-04362-x
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