临床试验设计可行性研究

STUDY_DESIGN_PROCEDURES.md

Detailed procedures for each of the 6 research paths in the clinical trial design feasibility assessment.

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PATH 1: Patient Population Sizing

Steps

1. Disease prevalence lookup: Use OpenTargets_get_disease_id_description_by_name then OpenTargets_get_diseases_phenotypes_by_target_ensembl
2. Biomarker prevalence: Use ClinVar_search_variants (gene + significance) and gnomad_search_variants
3. Literature epidemiology: Use PubMed_search_articles for prevalence, incidence, geographic distribution
4. Enrollment feasibility: Use search_clinical_trials to find past trials and enrollment rates

Enrollment Funnel Calculation

Base disease population (incidence/year)
x Biomarker prevalence (%)
x Eligibility factors (age, PS, prior therapy, organ function): ~60%
/ Competing trials factor
= Available patients/year

Geographic Considerations

• Some biomarkers have ethnic variation (e.g., EGFR mutations: 15% Caucasian, 50% Asian)
• Consider international sites for biomarker-enriched populations

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PATH 2: Biomarker Prevalence & Testing

Steps

1. Variant pathogenicity: ClinVar_get_variant_details
2. Cancer-specific frequency: COSMIC_search_mutations
3. Population genetics: gnomad_get_variant
4. CDx and testing: PubMed_search_articles for FDA-approved companion diagnostics, NCCN guidelines

Testing Logistics to Assess

• Pre-screening vs. screening approach
• Central lab vs. local testing
• Tissue vs. liquid biopsy (ctDNA)
• Turnaround time, cost, quality control

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PATH 3: Comparator Selection

Steps

1. Drug info: drugbank_get_drug_basic_info_by_drug_name_or_id
2. Indications: drugbank_get_indications_by_drug_name_or_drugbank_id
3. Pharmacology: drugbank_get_pharmacology_by_drug_name_or_drugbank_id
4. Generic availability: FDA_OrangeBook_search_drug
5. Approval details: OpenFDA_get_approval_history
6. Historical controls: search_clinical_trials for completed trials with SOC

Design Options to Evaluate

• Single-arm vs. historical SOC: Faster, smaller N, but selection bias
• Randomized vs. SOC: Robust, regulatory preferred, but 2x enrollment
• Non-inferiority: When aiming for better safety with similar efficacy

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PATH 4: Endpoint Selection

Steps

1. Precedent trials: search_clinical_trials (condition + phase + status=completed)
2. FDA acceptance: PubMed_search_articles for accelerated approval endpoints
3. Approval history: OpenFDA_get_approval_history for endpoints used in approvals

Endpoint Hierarchy (Oncology)

Endpoint	Evidence Grade	Use Case
Overall Survival (OS)	A	Phase 3, confirmatory
Progression-Free Survival (PFS)	A	Phase 2/3
Objective Response Rate (ORR)	A	Phase 2, accelerated approval
Duration of Response (DoR)	B	Secondary in Phase 2
Biomarker response	C	Exploratory

Statistical Considerations

• Expected effect size (from precedent trials)
• Null hypothesis (from SOC data)
• Sample size calculation (alpha=0.05, beta=0.20)
• Adaptive designs (Simon 2-stage, BOIN for dose escalation)

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PATH 5: Safety Endpoints & Monitoring

Steps

1. Mechanism-based toxicity: drugbank_get_pharmacology_by_drug_name_or_drugbank_id (class drug)
2. FDA warnings: FDA_get_warnings_and_cautions_by_drug_name
3. Real-world AEs: FAERS_search_reports_by_drug_and_reaction, FAERS_count_reactions_by_drug_event
4. DLT definitions: PubMed_search_articles for Phase 1 DLT in similar drug class

Safety Monitoring Plan Components

• DLT definition and assessment period
• Organ-specific monitoring (hepatic, cardiac, renal)
• Safety Monitoring Committee composition and review frequency
• Stopping rules

Dose Escalation Designs

• 3+3: Simple, standard, conservative
• BOIN: Bayesian, more efficient, adaptive
• mTPI: Model-based, flexible

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PATH 6: Regulatory Pathway

Steps

1. Breakthrough designations: PubMed_search_articles for FDA breakthrough in indication
2. Orphan drug eligibility: Calculate US prevalence (<200,000 total)
3. FDA guidance: PubMed_search_articles for relevant FDA guidance documents
4. Approval precedents: OpenFDA_get_approval_history for similar drugs

FDA Pathway Options

Pathway	Criteria	Benefits
505(b)(1)	New molecular entity	Full exclusivity
505(b)(2)	Relies on published safety data	Faster, smaller safety package
Breakthrough Therapy	Substantial improvement on serious condition	Rolling review, frequent FDA meetings
Orphan Drug	Prevalence <200,000 in US	7-year exclusivity, tax credits, fee waivers
Fast Track	Serious condition, unmet need	Rolling review
Accelerated Approval	Surrogate endpoint reasonably likely to predict benefit	Earlier approval, confirmatory trial required

Pre-IND Meeting Topics

1. Primary endpoint acceptability
2. Biomarker test qualification (CDx plan)
3. Comparator arm (single-arm acceptable?)
4. Pediatric study plan waiver
5. Safety monitoring plan

IND Timeline

Milestone	Month	Deliverable
Pre-IND meeting request	-4	Briefing package
Pre-IND meeting	-3	FDA feedback
IND submission	0	Complete IND package
FDA 30-day review	1	Clinical hold or proceed
First patient dosed	1-2	After IND clearance