Are there drug interactions between teriflunomide and Saphnelo (anifrolumab)

Drug Interactions Between Teriflunomide and Anifrolumab (Saphnelo)

There are no documented clinically significant drug interactions between teriflunomide and anifrolumab (Saphnelo). Based on the available evidence, these medications can be safely co-administered without dose adjustments or special monitoring.

Mechanism of Action and Metabolism

Teriflunomide

• Mechanism: Inhibits dihydroorotate dehydrogenase, affecting rapidly proliferating lymphocytes by blocking de novo pyrimidine synthesis 1
• Metabolism: Primarily hepatic metabolism
• Approved for: Relapsing forms of multiple sclerosis

Anifrolumab (Saphnelo)

• Mechanism: Monoclonal antibody that binds to type I interferon receptor
• Metabolism: Protein catabolism (not through cytochrome P450 pathways)
• Approved for: Systemic lupus erythematosus

Evidence for Lack of Interaction

The 2022 American College of Rheumatology guidelines for vaccinations in patients with rheumatic diseases list both teriflunomide and anifrolumab separately in their medication management recommendations, but do not indicate any special considerations for their combined use 2. This suggests no known problematic interactions between these medications.

Teriflunomide's known drug interactions primarily involve:

• Drugs metabolized by CYP2C8 (limited effect)
• Warfarin (requiring INR monitoring)
• Oral contraceptives (potential increased exposure)

Anifrolumab, as a monoclonal antibody, has minimal potential for drug interactions through metabolic pathways.

Clinical Considerations

Immunosuppressive Effects

Both medications have immunomodulatory effects:

• Teriflunomide has demonstrated safety in long-term studies with no increased risk of severe infections, opportunistic infections, or malignancies compared to other disease-modifying therapies 3
• When combining immunomodulatory therapies, theoretical concerns about additive immunosuppression exist, though no specific data indicates problems with this particular combination

Monitoring Recommendations

While no specific interaction monitoring is required, routine monitoring recommended for each medication individually should continue:

1. Liver function tests:

   • Teriflunomide can cause elevated liver enzymes 4, 5
   • Monitor ALT/AST at baseline and periodically

2. Complete blood count:

   • Both medications can affect immune cell populations
   • Regular monitoring is prudent

3. Infection surveillance:

   • Be vigilant for signs of infection due to the combined immunomodulatory effects

Practical Management

When prescribing both medications concurrently:

• No dose adjustments are required
• Continue standard monitoring protocols for each medication
• Educate patients about infection prevention strategies
• Consider vaccination status and needs before initiating therapy (note that live vaccines require temporary discontinuation of both medications)

In conclusion, while all combination therapies should be monitored appropriately, there is no evidence suggesting a clinically significant pharmacokinetic or pharmacodynamic interaction between teriflunomide and anifrolumab that would necessitate dose adjustments or contraindicate their concurrent use.