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Phase 1 vs. Phase 2 Trials: CRO Support Across Clinical Milestones

As a drug candidate progresses from first-in-human studies to broader patient testing,  each clinical trial phase introduces new complexities, risks, and regulatory requirements. Understanding the differences between Phase 1 and Phase 2 trials is essential for planning—and executing—your development strategy effectively.

At InfinixBio, we help bridge preclinical and clinical programs by supporting Phase 1 and Phase 2 trial readiness through integrated CRO services.

What Happens in Phase 1 Trials?

Phase 1 trials are typically conducted in healthy volunteers and are designed to answer the question: Is this drug safe in humans?

Key goals include:

• Evaluating safety and tolerability
• Characterizing pharmacokinetics (PK) and pharmacodynamics (PD)
• Determining maximum tolerated dose (MTD)
• Identifying any dose-limiting toxicities (DLTs)

Phase 1 trials are small (20–100 subjects), short in duration, and often include dose escalation cohorts.

What Changes in Phase 2 Trials?

Phase 2 trials expand into target patient populations to assess whether the drug works and at what dose. This is often called the “proof of concept” stage.

Key objectives include:

• Establishing preliminary efficacy
• Confirming dose range and regimen
• Continuing safety evaluation in a larger group (100–300 patients)
• Refining biomarkers and endpoints for Phase 3 design

Phase 2 is typically divided into:

• Phase 2a (exploratory efficacy)
• Phase 2b (dose optimization and decision-making)

How CROs Add Value Across Both Phases

Partnering with a CRO like InfinixBio provides critical support in:

• Trial design and protocol development based on preclinical PK/PD data
• Clinical bioanalysis with validated methods for PK, PD, and immunogenicity
• Biostatistics and data interpretation to support go/no-go decisions
• Regulatory submission support, including safety updates and IND amendments
• Coordination with clinical sites, vendors, and contract manufacturing organizations (CMOs)

In both phases, speed, quality, and compliance are key—and experienced CROs are built to deliver on all three.

InfinixBio’s Clinical Transition Services

We provide seamless support from preclinical through Phase 2 with:

• IND-enabling toxicology, DMPK, and bioanalysis
• Custom assay development for Phase 1/2 biomarker analysis
• PK/PD modeling to support dose selection and adaptive trial design
• Scientific guidance for trial planning, execution, and interpretation
• Strategic alignment with clinical CRO partners

Our approach ensures your clinical studies are grounded in robust science and regulatory clarity.

Navigate Clinical Milestones with Confidence

From safety in healthy volunteers to proof of concept in patients, Phase 1 and Phase 2 trials  are critical inflection points. With InfinixBio, you gain a trusted CRO partner to guide your molecule through these milestones efficiently and effectively. Contact us to learn more about how we can support your next project.