Doxycycline
| Evidence Level: L4 | Predicted Indications: 10 |
Table of Contents
Doxycycline: From Antibacterial Therapy to Punctate Epithelial Keratoconjunctivitis
One-Sentence Summary
Doxycycline is a tetracycline-class antibiotic that is widely marketed in the United States as oral tablets and capsules. The TxGNN model predicts it may be effective for punctate epithelial keratoconjunctivitis, but 0 clinical trials and only 1 publication (a 1992 two-case report) currently support this direction, so the prediction rests almost entirely on the model.
Quick Overview
| Item | Content |
|---|---|
| Predicted New Indication | Punctate epithelial keratoconjunctivitis |
| TxGNN Prediction Score | 99.94% |
| Evidence Level | L4 |
| US Market Status | ✓ Marketed |
| Number of NDAs | 20 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Doxycycline is a tetracycline-class antibacterial with established activity against many bacteria, including Chlamydia trachomatis. Mechanistically, it may be applicable to punctate epithelial keratoconjunctivitis when an infectious trigger is involved.
The only supporting paper describes two patients with chlamydial follicular conjunctivitis. They were treated with oral tetracycline or doxycycline, and the follicles resolved. Both then developed recurrent punctate epithelial keratitis. The link is therefore treatment of the infectious cause, not a new mechanism of action. The report also shows the keratitis appeared after antibiotic treatment, so it does not show that doxycycline treats the keratitis itself.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 1424659 | 1992 | Case report (2 cases) | Cornea | Recurrent punctate epithelial keratitis appeared after chlamydial follicular conjunctivitis had resolved with oral tetracycline or doxycycline |
US Market Information
The five main authorizations are all generic (ANDA) products. Approved indication text is not available in the data.
| Authorization Number | Product Name | Dosage Form | Manufacturer |
|---|---|---|---|
| ANDA062505 | Doxycycline Hyclate | Tablet, film coated | Proficient Rx LP |
| ANDA207289 | Doxycycline Hyclate | Capsule | Bryant Ranch Prepack |
| ANDA062396 | Doxycycline Hyclate | Capsule | Northwind Health Company, LLC |
| ANDA062396 | Doxycycline Hyclate | Capsule | Hikma Pharmaceuticals USA Inc. |
| ANDA065055 | Doxycycline | Capsule | Strides Pharma Science Limited |
All routes listed are oral (film-coated tablet, coated tablet and capsule). No ophthalmic formulation appears in the data.
Safety Considerations
Please refer to the package insert for safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The model score is very high, but the evidence is one 1992 two-case report with no clinical trials. That report does not show that doxycycline treats the keratitis. The safety data needed for screening are also missing.
To proceed, the following is needed:
- Package insert warnings and contraindications (a blocking data gap for safety screening)
- Mechanism of action data for doxycycline
- Controlled clinical evidence in punctate epithelial keratoconjunctivitis, for example from a targeted literature search
- Confirmation of a suitable route of administration, since only oral products are marketed
- As an alternative, the same Evidence Pack’s “post-bacterial disorder” and “post-infectious syndrome” predictions have stronger trial support (L2). Examples are the completed Q fever fatigue syndrome trial NCT01318356 and the Phase 3 doxycycline host-directed therapy trial in tuberculosis NCT05473520. These may be worth reviewing first.
This report is for research reference only and does not constitute medical advice. Repurposing candidates require clinical validation before any use.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.