Erythropoiesis-Stimulating Agents Do Not Adversely Affect Long-Term Outcomes Nor Increase the Risk of Thromboembolic Events in Multiple Myeloma Patients Treated in the Phase III VISTA Trial.

Introduction: Treatment of myeloma-associated anemia (both disease and treatment induced) includes erythropoiesis-stimulating agents (ESA) and/or red-blood-cell transfusions (RBCT). Limited data from patient subsets in retrospective studies have suggested that ESA may have a detrimental effect on outcomes, including reduced time-to- progression (TTP) and overall survival (OS), in patients with multiple myeloma (MM). Furthermore, ESA may increase the risk of deep-vein thrombosis (DVT) and pulmonary embolism (PE), especially in patients receiving immunomodulatory-based regimens and/or anthracyclines with glucocorticoids. Since the impact of ESA use on long-term outcomes and thromboembolic events in MM has not been extensively evaluated, we conducted a sub-analysis of the prospective multi-center, randomized, phase III VISTA trial in frontline MM (San Miguel et al. Blood 2007), to assess the potential impact of ESA use on TTP, OS and rates of DVT/PE.

Methods: Patients were randomized to receive nine 6-week cycles of bortezomib (1.3 mg/m² on days 1, 4, 8, 11, 22, 25, 29, and 32, cycles 1–4, and days 1, 8, 22, and 29, cycles 5–9) plus melphalan (9 mg/m²) and prednisone (60 mg/m²) administered on days 1–4 of each cycle (VMP; n=340) or melphalan–prednisone (MP; n=337) alone. No protocol-specified antithrombotic prophylaxis was required. Baseline characteristics, including age, sex and disease characteristics, were similar between ESA and non-ESA groups.

Results: Median Hb level at the time of ESA initiation was 9.75 g/dl in the VMP arm and 9.30 g/dl in the MP arm; consistent with current guidelines that ESA should not be initiated until Hb is <10 g/dl. The incidence of treatment-emergent anemia (defined as Hb < 8.0 g/dl) was lower in the VMP arm (23%) than the MP arm (33%), and fewer patients in the VMP versus MP arm were treated with ESA (30% vs 39%, respectively; erythropoietins 20% vs 24% and darbepoietin 11% vs 18%, respectively), or RBCT (26% vs 35%, respectively), potentially reflecting greater anti-myeloma activity with VMP. Median TTP was similar between patients who received ESA and those who did not in both treatment groups (Table). While one-year OS rates were similar, 2-year OS rates appeared higher for patients receiving ESA (Table). TE complications were low in both treatment arms and were not affected by ESA use (3% vs 2% for VMP, and 3% vs 1% for MP, for patients receiving or not receiving ESA, respectively).

Conclusions: Our post-hoc analysis from a large, well-controlled multicenter phase III trial in frontline MM shows that ESA use did not adversely impact long-term outcomes with VMP or MP, and may be associated with a survival benefit. Furthermore, ESA use did not appear to increase the risk of TE complications with VMP or MP. These data suggest that ESA can be safely administered with VMP/MP for the treatment of anemia in frontline MM patients. Prospective, randomized studies are needed to further investigate the relationship between ESA and RBCT use, other agents and long-term outcomes in MM patients.

Table. TTP and OS rates by ESA and RBCT use and per treatment