Grafalon

Grafalon is a rabbit-derived anti‑thymocyte globulin for human use, supplied as a sterile solution for injection. The product contains polyclonal antibodies that target multiple T‑cell surface antigens. While the exact strength is not specified, Grafalon is administered intravenously under prescription. It belongs to the immunosuppressant class and is marketed in the European Union for transplant‑related indications. It is used to prevent graft‑versus‑host disease and to treat rejection episodes in transplantation.

Grafalon is indicated for specific transplant-related situations where modulation of the immune response is required.

- Prevention of graft‑versus‑host disease (GVHD) in patients undergoing hematopoietic stem cell transplantation. - Treatment of acute cellular rejection in solid‑organ transplants such as kidney, liver, or heart. - Part of conditioning regimens prior to allogeneic stem cell transplantation to reduce host T‑cell activity. - Adjunct therapy in desensitization protocols for highly sensitized transplant candidates. - Use in clinical trials evaluating novel immunosuppressive strategies. - Pre‑transplant lymphocyte depletion in patients with high immunologic risk undergoing bone marrow transplantation.

The immunologic activity of Grafalon can produce a range of adverse reactions, which are generally categorized as common or serious based on frequency and clinical impact.

Common: - Fever, chills, or rigors during or shortly after infusion. - Nausea, vomiting, or mild gastrointestinal discomfort. - Transient lymphopenia with reduced peripheral T‑cell counts. - Mild hypotension or flushing that resolves with slowing the infusion rate. - Headache or mild dizziness during infusion.

Serious: - Severe cytokine release syndrome presenting with high fever, hypotension, and respiratory distress. - Acute hemolytic anemia or thrombocytopenia. - Opportunistic infections such as cytomegalovirus reactivation. - Serum sickness–like reactions with rash, arthralgia, and fever. - Renal impairment or acute kidney injury associated with T‑cell depletion.

Before initiating Grafalon therapy, clinicians should evaluate several precautionary factors to minimize risks and ensure appropriate patient selection.

- Assess baseline complete blood count and renal function, as Grafalon can exacerbate cytopenias and affect kidney performance. - Screen for active infections, including viral (CMV, EBV) and bacterial pathogens, because immunosuppression may worsen them. - Evaluate pregnancy status; the drug’s safety in pregnancy has not been established. - Consider the patient’s immunologic risk profile; high‑risk individuals may require dose adjustments or additional monitoring. - Monitor for infusion‑related reactions and be prepared to manage cytokine release syndrome. - Review concomitant use of other potent immunosuppressants to avoid excessive immune depletion.

Grafalon may interact with other medications, and understanding these relationships helps to avoid adverse events or reduced efficacy.

Avoid: - Concurrent use of other T‑cell depleting agents (e.g., alemtuzumab) due to additive immunosuppression. - Live vaccines administered during or shortly after treatment, because immune response may be insufficient. - High‑dose corticosteroids without dose adjustment, which can increase infection risk. - Use of nephrotoxic drugs (e.g., aminoglycosides) may exacerbate renal impairment.

Use with caution: - Antimicrobial prophylaxis agents (e.g., trimethoprim‑sulfamethoxazole) as bone‑marrow suppression may be enhanced. - Calcineurin inhibitors (cyclosporine, tacrolimus) requiring close therapeutic drug monitoring. - Antiviral drugs (ganciclovir, valganciclovir) due to potential overlapping myelosuppressive effects.