Regimens

A regimen is a named treatment protocol composed of one or more interventions. Three entities model this domain: regimens, interventions, and the bridge table regimen_interventions.

Domain context

“Pembrolizumab + carboplatin + pemetrexed” is a single regimen containing three interventions. Each intervention can be a drug, a procedure, radiation, a device, or another treatment modality. The regimen captures the protocol as a whole — its evidence level, disease stages, and classification — while each intervention carries its own dosing, schedule, and route of administration.

Entities

erDiagram
    regimens ||--o{ regimen_interventions : "composed of"
    regimen_interventions }o--|| interventions : "references"
    interventions }o--o| drugs : "optional FK"

regimens — named treatment protocols

One row per defined treatment protocol. Covers monotherapy, combination, and fixed-dose combination regimens.

Column	Purpose
name	Regimen name (e.g., “FOLFOX”, “R-CHOP”, “pembrolizumab monotherapy”)
ncit_code	NCI Thesaurus code for named regimens (e.g., C63514 for FOLFOX). Unique.
regimen_type	monotherapy, combination, or fixed_dose_combination
disease_stages	JSON array of disease stages this regimen targets
evidence_level	Strength of evidence: A (guideline/FDA approved), B (clinical trial), C (preclinical), D (computational)
synonyms	JSON array of alternative names
description	Free-text description of components and schedule

Indexed on ncit_code and regimen_type.

interventions — individual treatment components

One row per treatment component. An intervention can represent a drug, biological, procedure, radiation, device, behavioral intervention, diagnostic test, or dietary supplement.

Column	Purpose
name	Intervention name (e.g., “pembrolizumab”, “radiation therapy”, “surgery”)
intervention_type	drug, biological, procedure, radiation, device, behavioral, diagnostic_test, dietary_supplement
dose	Dosing information as text (e.g., “200 mg Q3W”, “2 mg/kg”)
route_of_administration	Route (e.g., intravenous, oral, subcutaneous)
schedule	Dosing schedule description (e.g., “every 3 weeks”, “daily x 21 days”)
drug_id	FK to drugs.id. Set when the intervention is a drug or biological; null otherwise. On delete: set null.

Indexed on drug_id and intervention_type.

regimen_interventions — bridge table

Links interventions to regimens with ordering and role metadata. A unique constraint on (regimen_id, intervention_id) prevents duplicate pairings.

Column	Purpose
regimen_id	FK to regimens.id. On delete: cascade.
intervention_id	FK to interventions.id. On delete: cascade.
sort_order	Display order within the regimen (0-based)
role	backbone, combination_partner, supportive, optional

Design decisions

• Interventions are separate from drugs. Not every intervention is a drug — procedures, radiation, and devices are first-class treatment components. When an intervention is a drug, the optional drug_id FK links it back to the drugs domain.
• Regimens are normalized and reusable. The same regimen can appear across multiple clinical trials and treatment guidelines without duplication. This keeps guideline and trial data consistent when a regimen definition is updated.
• Interventions bridge clinical trials to drugs. The trial_arm_interventions table (in the clinical trials domain) references interventions, not drugs directly. This lets trial arms include non-drug components while still resolving back to drug records when applicable.

Example queries

List all interventions in a regimen, ordered by their role and position:

select
    r.name         as regimen,
    i.name         as intervention,
    i.intervention_type,
    ri.role,
    ri.sort_order,
    i.dose,
    i.schedule
from regimens r
join regimen_interventions ri on ri.regimen_id = r.id
join interventions i on i.id = ri.intervention_id
where r.name = 'FOLFOX'
order by ri.sort_order;

Find all regimens that include a specific drug:

select distinct
    r.name          as regimen,
    r.regimen_type,
    r.evidence_level,
    d.name          as drug_name
from regimens r
join regimen_interventions ri on ri.regimen_id = r.id
join interventions i on i.id = ri.intervention_id
join drugs d on d.id = i.drug_id
where d.name = 'pembrolizumab';