Is Retacrit Equivalent to Epogen?
Yes, Retacrit (epoetin alfa-epbx) is equivalent to Epogen (epoetin alfa) for treating anemia in patients with chronic kidney disease and cancer, with comparable effectiveness and safety profiles. 1, 2
Guideline-Based Equivalence
The ASCO/ASH 2019 clinical practice guideline explicitly states that biosimilar epoetin alfa products (including Retacrit) are considered equivalent to originator epoetin alfa products with respect to effectiveness and safety. 1 This recommendation applies to both cancer-associated anemia and chronic kidney disease populations. 1
Supporting Clinical Evidence
Head-to-Head Comparison Study
A randomized, non-inferiority trial specifically evaluated switching from Epogen to Retacrit in hemodialysis patients using a standardized dosing algorithm. 3 Key findings include:
- 61.9% of patients maintained hemoglobin in the target range (9-11 g/dL) with Retacrit versus 63.3% with Epogen 3
- The difference was -1.4% (95% CI -7.6 to 4.9), meeting non-inferiority criteria 3
- No statistically significant difference in mean ESA dose requirements between groups 3
- No clinically relevant differences in safety outcomes 3
Meta-Analysis Data
Multiple meta-analyses in chronic kidney disease populations found no significant differences between biosimilar and reference epoetin alfa in:
The evidence quality is described as low to moderate, primarily because most data comes from CKD rather than cancer populations. 1
Real-World Safety Experience
Biosimilar epoetin alfa products have been available in Europe for over 10 years without major safety concerns emerging. 1, 2 This extensive post-marketing experience provides reassurance about long-term safety equivalence.
Important Safety Caveat
One early biosimilar (HX575) trial was stopped when 2 patients developed antibodies to epoetin and pure red cell aplasia. 1 However, a subsequent larger trial of the same biosimilar showed binding antibodies developed in 2.8% of biosimilar patients versus 0.5% with reference product, but no patients developed neutralizing antibodies. 1
Clinical Application Recommendations
For Cancer-Associated Anemia
- Offer ESAs (including Retacrit) when hemoglobin declines to <10 g/dL in patients receiving non-curative chemotherapy 1, 2
- Target the lowest hemoglobin concentration needed to avoid transfusions, not exceeding 12 g/dL 2
- RBC transfusion remains an alternative option 2
For Chronic Kidney Disease
- Assess and correct iron deficiency before initiating any ESA 4, 2
- Maintain hemoglobin between 10-12 g/dL 5
- Avoid targeting hemoglobin >13 g/dL due to increased mortality and cardiovascular events 4
Critical Safety Considerations (Apply to All ESAs)
All ESAs, including both Retacrit and Epogen, carry significant risks: 2
- Increased mortality, myocardial infarction, and stroke when targeting hemoglobin >11 g/dL 2
- 50-75% increased risk of thromboembolic events 1
- Particular caution needed in patients with history of thrombosis, recent surgery, or prolonged immobilization 2
Dosing Adjustments
Reduce dose by 25-50% if: 2
- Hemoglobin rises >2 g/dL per 4 weeks
- Hemoglobin exceeds 12 g/dL
Common Pitfalls to Avoid
- Failing to assess iron status before initiating therapy leads to inadequate response 4
- Targeting hemoglobin above 12 g/dL increases cardiovascular risk 4
- Using ESAs in cancer patients not receiving chemotherapy or when cure is anticipated is not recommended 4
- Overlooking alternative causes of anemia (inflammation, infection, blood loss, folate deficiency) contributes to poor response 4
Bottom Line for Clinical Practice
The choice between Retacrit and Epogen should be based on cost, availability, and institutional preference rather than efficacy or safety concerns, as they are therapeutically equivalent. 1, 2 Both require identical monitoring, dosing adjustments, and safety precautions. 2