How to Choose a CRO for Phase 1 and Phase 2 Clinical Trials
Selecting a CRO for an early-phase study is a different decision than selecting one for a large, late-phase trial. For a broader overview of what a CRO does across all trial phases, including cost drivers and common mistakes, see our CRO clinical trials guide. This article focuses specifically on the criteria that matter most when your study is Phase I or Phase II.
Why Phase 1 and Phase 2 Require a Different Selection Approach
Phase I and Phase II trials carry a different risk profile than later-stage studies. Phase I is usually the first time an investigational drug is given to humans, so the priority shifts from operational scale to safety infrastructure, dosing precision, and rapid, high-quality pharmacokinetic (PK) and pharmacodynamic (PD) data. Phase II introduces the first patient population and the first real signal on efficacy, which raises the importance of protocol design flexibility, biostatistics for smaller sample sizes, and early endpoint selection.
A CRO that excels at large multi-country Phase III execution does not automatically have the specialized capabilities early-phase sponsors need. Evaluating CROs on the wrong criteria at this stage is one of the most common and costly mistakes sponsors make.
Phase I vs Phase II: What Changes in CRO Selection
Criteria | Phase I Priority | Phase II Priority |
Population | Typically healthy volunteers or a small patient cohort | Target patient population |
Primary focus | Safety, tolerability, dose escalation, PK/PD | Preliminary efficacy signal, dose selection, safety in target population |
Facility needs | Dedicated Phase I unit with continuous monitoring capability | Standard clinical sites with disease-specific expertise |
Data priority | Real-time safety data review, DSMB/SRC support | Endpoint-specific data quality, biostatistics for smaller n |
Regulatory | IND/CTA enabling package, first-in-human considerations | Protocol amendments, interim analysis support |
Checklist: What to Evaluate When Choosing a CRO for Phase 1 or Phase 2
- Access to dedicated early-phase infrastructure
For Phase I studies, confirm the CRO has direct access to a Phase I unit or clinic capable of continuous safety monitoring, not just general clinical sites repurposed for early-phase work. Ask how many first-in-human (FIH) studies the CRO has run in the last 2–3 years, and in which therapeutic areas.
- Dose-escalation and safety review experience
Ask the CRO to walk through their process for dose-escalation decisions, safety review committees (SRC/DSMB), and how quickly they can convene a safety review after a reported adverse event. Response time here is one of the clearest differentiators between CROs with genuine early-phase depth and those without it.
- PK/PD and bioanalytical capabilities
Confirm whether PK/PD analysis and bioanalytical lab work are handled in-house or outsourced to a partner lab. Either can work, but outsourced arrangements should have clearly defined turnaround times, since PK data often drives real-time dosing decisions in Phase I.
- Biostatistics for small-sample and adaptive designs
Phase I and Phase II trials often use adaptive designs, Bayesian dose-finding models, or small-n statistical approaches that differ meaningfully from the large, fixed-sample designs typical of Phase III. Ask for examples of adaptive or Bayesian designs the CRO’s biostatistics team has supported.
- Regulatory support for IND/CTA and first-in-human submissions
Early-phase trials require different regulatory expertise than confirmatory studies, particularly around IND-enabling packages, first-in-human risk assessments, and interactions with regulators on novel mechanisms. Ask which regulatory authorities (FDA, EMA, national agencies) the CRO’s team has direct submission experience with for early-phase programs.
- Recruitment strategy fit for the population
Phase I healthy-volunteer recruitment and Phase II patient recruitment require different networks and strategies entirely. A CRO strong in patient recruitment for a common indication may have little to no healthy-volunteer database — verify this directly rather than assuming general recruitment strength transfers across phases.
- Risk-based monitoring calibrated to early-phase risk
Because early-phase studies are higher-risk per patient but smaller in scale, monitoring plans should be calibrated accordingly, often with more intensive, faster-cycle monitoring than a typical risk-based approach used in Phase III.
- Transition planning to the next phase
Ask how the CRO supports (or hands off) the transition from Phase I to Phase II, or Phase II to Phase III, including data continuity, site relationships that carry forward, and lessons from the earlier phase that inform the next protocol. A CRO that can support a program across phases reduces onboarding friction and preserves institutional knowledge about your compound.
Questions to Include in Your Phase 1/2 CRO RFP
- How many Phase I / Phase II studies has your team completed in this therapeutic area in the past 3 years?
- What is your average time from a reported serious adverse event to safety review committee convening?
- Do you have in-house bioanalytical/PK capability, or which partner labs do you use?
- What adaptive or Bayesian design experience does your biostatistics team have?
- What is your healthy-volunteer database size and geographic coverage (for Phase I)?
- How do you structure governance and reporting cadence specifically for early-phase studies?
Red Flags to Watch For
- Vague or generic answers about safety review timelines
- No dedicated Phase I unit access, or reliance on a single third-party site with no visibility into its performance history
- Biostatistics team that defaults to standard fixed-sample designs without adaptive design experience
- Inability to name specific past IND/CTA submissions they supported
- Pricing based purely on a standard Phase III cost model applied to an early-phase study — a sign the CRO hasn’t adjusted its approach to your trial’s actual risk profile
FAQ
How do I choose a CRO for a Phase 1 clinical trial? Prioritize CROs with direct access to a dedicated Phase I unit, demonstrated dose-escalation and safety review experience, and in-house or tightly integrated PK/PD and bioanalytical capabilities. Ask for specific examples of first-in-human studies they have run in your therapeutic area.
How do I choose a CRO for a Phase 2 clinical trial? Focus on the CRO’s experience with your target patient population, their biostatistics capability for smaller or adaptive designs, and their track record supporting early efficacy signal detection and endpoint selection.
Is it better to use the same CRO across Phase 1 and Phase 2? Not always required, but it can reduce onboarding time, preserve continuity in site relationships and safety data history, and shorten the transition between phases, provided the CRO has genuine strength in both phases rather than only one.
Partner with Cromos Pharma for Your Early-Phase Trial
Cromos Pharma supports sponsors from first-in-human through Phase IV, with dedicated early-phase experience across multiple therapeutic areas and a global site network built for both healthy-volunteer and patient-population studies.
Contact us to discuss your Phase I or Phase II trial, or read our full CRO clinical trials guide for a broader overview of CRO selection across all phases.
