Human clinical trials are supposed to answer one simple question: does this treatment work, and is it safe? But the first time a new drug is given to a person, known as a first in human study, is where many biotech programs quietly go wrong. The problem is rarely bad luck. It is usually study design, particularly when a first-in-human study is planned without enough attention to dose selection, regulatory strategy, feasibility and recruitment. 

A poorly planned first-in-human trial can cost a program 12 to 18 months and well over a million dollars in delays. It can also produce data that regulators do not accept, forcing the sponsor to run part of the study again. Here is what early-stage biotechs commonly get wrong when planning FIH clinical trials, and one important gap that most advice on this topic leaves out. 

Mistake 1: Thinking It Is Just a Safety Check 

Many teams still picture early phase clinical trials as a simple test: give a low dose, watch for side effects, then slowly raise the dose. That model is outdated. 

Modern first-in-human protocols often combine several things at once: 

• Single ascending dose and multiple ascending dose testing 

• Food effect sub-studies 

• Early biomarker sampling 

• Patient cohorts, not only healthy volunteers 

If a sponsor plans for the simple version and the regulator expects the complex version, the study needs to be redone. That means lost time and lost money. 

This is why the scope of the study should be set before the protocol is written, not adjusted after the regulator sends back questions. Early involvement of a CRO can help sponsors evaluate study feasibility, protocol requirements and operational considerations before the first-in-human protocol is finalized. A short internal review with clinical and regulatory experts, done early, is far cheaper than a rejected submission later. Sponsors can also involve specialist medical writers early to translate the study concept into a clear protocol and supporting clinical documentation. 

Mistake 2: Assuming One Region’s Rules Apply Everywhere 

A dose justification method or safety stopping rule that works for one regulator may not satisfy another. The US, the UK, and the EU can each ask different questions about the same protocol. 

Some regions also offer real advantages. Certain countries can get a first patient dosed within five to six weeks, offer tax rebates on research spending, and still produce data that the FDA and EMA accept. Biotechs that choose a region out of habit, instead of strategy, leave time and money on the table. 

The lesson here is simple. Regulatory strategy and geography should be decided together, early in planning, not treated as two separate conversations that happen months apart. Early regulatory input can also help sponsors identify submission requirements before protocol decisions become difficult to change. 

Mistake 3: Switching Vendors Between Phases 

Choosing one CRO for Phase 1 study design and a different one for Phase 2 sounds harmless. Before deciding how much of the program to outsource, sponsors should also consider whether a full-service CRO or functional model better fits the development program. In practice, it usually means: 

• Re-explaining the molecule to a new team 

• Rebuilding relationships from scratch 

• Losing knowledge about decisions made earlier in the program 

This kind of fragmentation is a common reason programs slow down right when they should be speeding up. 

Mistake 4: Bringing In Experts Too Late 

Draft protocols that arrive at the CRO stage often have unclear dose escalation logic, unrealistic cohort sizes, or missing safety stopping rules. Fixing these problems after the protocol is written costs far more than catching them early. 

“Specialists in clinical pharmacology, biostatistics, medical writing and regulatory strategy should review the plan at the synopsis stage, ideally before the trial start. Early biostatistical input can help sponsors address sample-size assumptions, randomization, statistical analysis requirements and the data needed to support decisions in later phases, ideally a year or two before the trial starts. Waiting until “later” almost always means waiting too long. 

Mistake 5: Designing for Tolerability, Not for Decisions 

Regulators no longer just want proof that a drug was tolerated. They want justification for the dose chosen for the next phase. In practice, this means: 

• Building exposure-response data from day one 

• Confirming the drug is reaching its intended target 

• Testing biomarker hypotheses, not just collecting samples 

A 2024 industry survey found that 38 percent of biotechs named regulatory compliance as their top Phase 1 challenge, and 35 percent named biomarker selection. These are widespread problems, not rare ones. 

The Gap Nobody Talks About: Can You Actually Enroll the Trial? 

Most advice on study design focuses on dose logic, regulatory strategy, and vendor choice. Very little of it treats participant recruitment as part of the design itself. 

But who you can enroll, and how fast, affects everything else: 

Design Choice	What Recruitment Reality Affects
Cohort size and timeline	Site density and volunteer availability
Population diversity	Regulatory expectations under diversity action plans
Data quality	Screen-fail rates and how representative the data is
Program risk	Ability to spot slow enrollment early

A scientifically sound dose escalation plan does not help much if the target population cannot be enrolled within the assumed timeline. Real-time visibility into enrollment and safety data, supported by EDC and IWRS platforms, can help sponsors and study teams identify recruitment or operational issues earlier, lets sponsors catch problems early instead of at the end of the study. 

For early-stage biotechs, site and population feasibility should be checked before the protocol is finalized, not after it. A CRO with a wide, active site network can often tell you within days whether a cohort is realistic, well before the protocol is locked and the timeline is promised to investors. Once sites are selected, effective site management and monitoring become equally important for maintaining protocol compliance, participant safety and study timelines. 

A Quick Pre-Protocol Checklist

 

• Has the dose justification method (NOAEL, MABEL, or hybrid) been agreed? 

• Is the target region and regulatory pathway decided before the protocol is written? 

• Does your CRO partner have the depth to carry the program past Phase 1? 

• Have specialists reviewed the synopsis, not just the final draft? 

• Does the design generate decision-making data, not just tolerability data? 

• Has enrollment feasibility, including diversity, been checked against the timeline? 

Final Thoughts 

Getting first in human study design right is not about avoiding every mistake by chance. It comes from treating each decision, dose logic, region, vendor continuity, and recruitment feasibility, as one strategy, planned early. 

Human clinical trials succeed or struggle long before the first dose is ever given. The biotechs that move fastest through this stage are the ones that plan for it as a whole, not piece by piece. 

If you are preparing for your first-in-human trial, Innovate Research offers integrated Phase 1 to Phase 4 support, regulatory guidance, biostatistics, and a wide site and patient network across India, built to help you get study design right from the start. 

Our expert panel brings together industry leaders and medical specialists to help ensure every trial meets rigorous ethical, scientific, and regulatory standards. Our other services include: 

• Medical writing 

• Clinical site management 

• Biospecimen collection 

• Biostatic management 

Visit Innovate Research to learn more about our services 

FAQs

 

1. How long does a first-in-human trial usually take?

The timeline varies by molecule, study design, number of cohorts and regulatory pathway. A simple Phase 1 study may take several months, while more complex studies with multiple cohorts, food-effect assessments or patient groups can take considerably longer.

2. Should a first-in-human study use healthy volunteers or patients?

That depends on the treatment and its risk profile. Healthy volunteers are common for many small molecules, while oncology drugs, gene therapies and treatments with higher expected toxicity are more often studied directly in patients.

3. What documents are usually needed before a first-in-human study can begin?

Sponsors typically need a clinical protocol, investigator brochure, informed consent documents, preclinical safety data, manufacturing information and regulatory submission materials. The exact requirements depend on the country and product type.

4. What is sentinel dosing in a first-in-human trial?

Sentinel dosing means giving the investigational treatment to a small number of participants first before dosing the rest of the cohort. It gives the study team time to review early safety observations before exposing more participants.

5. Who reviews safety during a first-in-human study?

Safety may be reviewed by the investigator team, sponsor medical monitors and a Safety Review Committee. Depending on the study’s risk and complexity, an independent Data Safety Monitoring Board may also be involved.