FcRn Inhibitors
4 drugsAbout FcRn
FcRn (neonatal Fc receptor) regulates immunoglobulin G (IgG) levels by binding and protecting IgG antibodies from degradation, effectively extending their half-life. This mechanism is exploited therapeutically to modulate IgG levels.
FcRn is a therapeutic target for autoimmune disorders and other antibody-mediated conditions. Human genetic studies provide moderate support for FcRn as a drug target, with variants linked to asthma (score 0.40).
Four FDA-approved drugs target FcRn, including VYVGART, VYVGART HYTRULO, RYSTIGGO, and IMAAVY. All four drugs are biologics (other) and address various therapeutic areas.
FcRn Genetic Evidence Moderate
Genetic evidence provides moderate support for FcRn, with the strongest association to asthma (score 0.40).
Further research into the genetic basis of FcRn's role in asthma may reveal novel therapeutic opportunities.
Evidence Across Diseases
10 totalGWAS and other genetic studies link FCGRT to 10 diseases.
🔗 Colocalization Evidence 20 strong
max H4: 1.00eQTL/pQTL signals for FCGRT colocalize with these GWAS traits, providing causal evidence that gene expression changes drive disease risk.
Understanding these scores
Association Score (0-1): Combines all evidence types (genetic, literature, drugs, animal models). Higher = more evidence linking target to disease. This is a ranking heuristic, not a confidence score.
L2G Score: Open Targets uses a machine learning model (Locus-to-Gene) to predict which gene is causal at each GWAS locus. L2G=0.5 means ~50% probability of being the causal gene. Only associations with L2G > 0.05 are included.
Odds Ratio (OR): From gene burden studies (UK Biobank, AstraZeneca PheWAS). Measures how loss-of-function variants affect disease risk. OR<1 = protective (inhibiting target may help), OR>1 = risk (losing function causes disease).
Beta (β): Effect size for continuous traits. β<0 = protective, β>0 = risk.
Clinical Translation (~1.8x): Based on Nelson et al. 2015: drug targets with genetic evidence have ~2x higher success rates in clinical trials. We estimate: Strong support (score ≥0.7) → ~1.8x, Moderate (0.3-0.7) → ~1.3x, Weak → baseline.
Colocalization (H4): Tests whether a GWAS signal and an eQTL/pQTL signal share the same causal variant. H4 is the posterior probability that both traits are associated AND share a causal variant. H4 > 0.8 = strong evidence that gene expression/protein levels drive disease risk. This links genetic variation → gene expression → disease, supporting the target-disease connection.
Top FcRn Drugs
Three companies have approved FcRn-targeting drugs: ARGENX BV, UCB INC, and Johnson & Johnson.
The relatively low number of companies suggests potential entry barriers or a concentrated market.
| Drug | Company | Approved | Indications |
|---|---|---|---|
| IMAAVY | Johnson & Johnson | 2025 | 1 |
FcRn Drug Modality Landscape
Modalities
Routes of Administration
FcRn requires biologic approaches (biologic (other)), likely due to its structure or location.
Exploring alternative modalities like small molecules could provide a competitive advantage in the FcRn space.
📈 Modality Evolution
Enzymes pioneered FcRn targeting (2021), with other biologics entering more recently (2023).
FcRn Clinical Trials 69 trials
Phase 1-4 trials started in 2008 or later that test an FDA-approved drug acting on FcRn. Source: ClinicalTrials.gov. How we count
Completion by Phase
| Phase | Total | Completed | Stopped | Active | Completion |
|---|---|---|---|---|---|
| Phase 1 | 11 | 9 | 0 | 2 | 100% |
| Phase 2 | 32 | 13 | 5 | 14 | 72% |
| Phase 3 | 23 | 7 | 4 | 12 | 64% |
| Phase 4 | 3 | 0 | 0 | 3 | - |
Top Sponsors
By Modality
Top Conditions
Top Drugs
FcRn Drug Approval Timeline (2021 - 2025)
The first FcRn-targeting drug was approved in 2021 (VYVGART), with the most recent approval in 2025 (IMAAVY).
The recent approvals suggest a growing interest and potential for further development in FcRn-targeted therapies.
Pro Intelligence Preview
Deep insights for drug target analysis
Competitive Landscape
- • 3 companies competing
- • Market share by company
Full Drug Portfolio
- • All 4 approved drugs
- • Approval dates & indications
Genetic Validation
- • Full genetic evidence table
- • Effect sizes & directions
Approval Timeline
- • Full 4-drug timeline
- • First-of-modality markers
Clinical Trials Analysis
- • Sponsors: 23 (6 companies)
- • Completion rates by condition
Full summary • All drugs • Genetic evidence • Trials • Timeline
How We Count Trials
- Trials: phase 1-4 interventional trials on ClinicalTrials.gov that started in 2008 or later and test an FDA-approved drug acting on FcRn. A trial counts if an approved drug acting on FcRn is in any arm, including as a comparator, and a trial that tests two such drugs counts once. Trials that test only unapproved drugs are not counted. A trial listed as phase 1/2 counts as phase 1, and phase 2/3 as phase 2.
- Active: recruiting, not yet recruiting, enrolling by invitation, or active and no longer recruiting.
- Completion rate: of the trials that have ended, the share marked Completed rather than Terminated or Withdrawn. Completed means the trial ended as planned; it does not mean the drug worked. Suspended trials are not counted as ended.
- Stopped: terminated or withdrawn. Trials stop for many reasons, including slow enrolment and business decisions, not only safety or efficacy.
- Sponsors: the lead sponsor of each trial. Companies are the sponsors ClinicalTrials.gov classes as industry; the rest are universities, hospitals, cooperative groups, government bodies and individuals.