BEAM Vs Melphalan Based Conditioning Therapy for Second Autologous Stem Cell Transplant (ASCT) for Multiple Myeloma (MM)

Background: Salvage ASCT is increasingly utilized for eligible MM patients (pts). High dose melphalan (HDM) is the standard conditioning used for 1^st ASCT. Despite concerns for resistance, HDM is predominantly used as conditioning regimen for 2^nd / or salvage ASCT. BEAM (Carmustine, etoposide, Ara-C and Melphalan) has shown superior PFS and OS compared to HDM during 1^st ASCT for MM pts. We conducted a single institution retrospective analysis to evaluate response and toxicity with BEAM conditioning in 2^ndASCT. 

Methods: Thirty two pts who received 2^nd ASCT for MM (2007-2013) were identified. Sixteen pts received HDM (140-200mg/m²; Group A) and an equal number received BEAM (carmustine 300 mg/m2, etoposide 100 mg/m2, cytarabine 100 mg/m2, and melphalan 140 mg/m2; Group B). Patient characteristics, toxicity and response at day 100 were collected and compared between the 2 groups. Fischer’s exact and Cochran-Mantel-Haenszel tests were used to compare responses and toxicities.

Results: The median age of the patients was 58 yrs (range: 39-72) in Group A and 58 yrs (range: 49-68) in Group B. Group A had more female pts (56% vs 25%) and a decreased baseline renal function (median creatinine clearance 76 vs 108 ml/min) compared to Group B. There was no significant difference in disease status pre-2^nd ASCT between the 2 groups. Salvage therapy was given to 12 pts in group A and 16 pts in group B.  The median time between 2 ASCTs were 29 (range: 3-67) months in group A vs 35.5 (range: 18-58) months in group B. All patients received stem cells which were collected and cryopreserved prior to the 1^stASCT. At day +100, seven patients from Group B had CR compared to 2 from group A (p=0.11) (Table 1). Patients who received BEAM had higher incidence of febrile neutropenia (16 vs 10 pts) and longer hospitalization (23 vs 15 days, p <0.0001). Other toxicities were not significantly different between these groups.

Conclusion: BEAM seems to be a viable and tolerable conditioning regimen for 2^ndASCT in MM pts. Further analyses including PFS and OS are planned to better define the two groups. 

Table-1: Data Summary

Variables	Group A, N=16	Group B, N=16
Age*   (yrs)	58 (39-72)	58 (49-68)
KPS*   (%)	70 (60-80)	70 (60-80)
Creatinine   Clearance pre 2nd ASCT* (ml/min)	76 (42-129)	108 (44-218)
CR   pre- 2nd ASCT [n (%)]	2 (12)	3 (14)
CD34+   cells infused for 2nd ASCT* (x 106 cells/kg)	3.35 (2.2-10.7)	3.12 (2.79-12.04)
Febrile   Neutropenia [n (%)]	10 (63)	16 (100)
In-patient   stay for 2nd ASCT* (days)	15 (12-24)	23 (19-51)
CR at   Day +100 post 2nd ASCT [n (%)]	2¶ (14)	7ξ (47)

KPS- Karnofsky’s Performance score

CR- Complete response

ASCT- Autologous Stem cell transplant

^* Values are median with range in parenthesis

^¶Day +100 response data not available for 2 patients in Group A

^ξ Day +100 response data not available for 1 patient in Group B