Fung, Sharon

Abstract One potential approach to improve the results of autologous stem cell transplantation (ASCT) in multiple myeloma (MM) involves the use of more potent induction regimens; the achievement of deeper remission pre-ASCT should translate into longer progression-free (PFS) and overall survival (OS). To evaluate this hypothesis, we assessed the influence of the percent reduction in serum monoclonal protein (M protein) pre-ASCT in patients (pts) treated with dexamethasone-based regimens (most often VAD) on the best response, PFS and OS achieved after ASCT. Between 2000–2006, 376 pts with IgG (267) or IgA (109) non-progressive MM underwent ASCT. Median age was 59 (21–73) yrs; 60% were male. The median hemoglobin at diagnosis was 103 g/L, creatinine 98 μmol/L, β2-microglobulin 241 nmol/L and albumin 35 g/L. Maintenance therapy was given to 84 (22%) after ASCT and consisted of corticosteroids in 29, thalidomide in 10, both in 41 and other regimens in 4 pts. Patients were divided into 4 groups based on the per cent reduction in M protein after induction therapy: group A, ≥ 99%; group B, 90–98%; group C, 50–89%; group D, < 50%. Post-ASCT responses included complete remission (CR), very good partial remission (VGPR) (≥ 90% reduction in M protein), PR (≥ 50% reduction) and stable disease (SD). Median follow-up from diagnosis is 37.4 mos and from ASCT 24.1 mos. For all pts, the median OS from diagnosis is 90.8 mos (95% CI 73.9–129.1 mos) and from ASCT 63.9 mos (95% CI 50.8–69.4 mos), while the median PFS from ASCT is 21.3 mos (95% CI 19.1–23.3 mos). Maintenance therapy had no significant effect on PFS (p=0.49) or OS (p=0.59). The post-ASCT results in evaluable patients according to the percent reduction in M protein after induction therapy are summarized below. We conclude: High-grade remissions after dexamethasone-based induction therapy are uncommon, with only 2% achieving ≥ 99% and 13% achieving 90–98% reduction in serum M protein; post-ASCT CR and VGPR rates were higher in these 2 groups; there was no significant difference in PFS or OS-based on protein response prior to transplant; whether newer induction regimens, which incorporate novel agents and which produce more CRs and VGPRs before ASCT, will confer better PFS and OS post-ASCT will be of great interest. Table 1 Group N CR (%)1 VGPR (%)1 PR (%)1 SD (%)1 Median PFS (mo)2 Median OS (mo)3 1p<0.001;2p=0.77;3p=0.79 A 7 50 50 Not reached Not reached B 47 19 64 17 23.3 Not reached C 232 14 17 68 1 20.7 59.1 D 87 11 7 54 28 21.1 69.4 Figure Figure Figure Figure

Abstract Abstract 3055 Lenalidomide (Revlimid®) and dexamethasone is an effective regimen for relapsed/refractory (rel/ref) multiple myeloma (MM) patients (pts) with an overall response rate of 60% and median time to progression of 13.4 months (Dimopoulos ME, et al. Leukemia 2009; 23: 2147-52). We combined lenalidomide with the alkylating agent combination of cyclophosphamide and prednisone—an older regimen with minimal cumulative myelosuppression and good activity as second or third line therapy (Trieu Y, et al, Mayo Clin Proc 2005; 80: 1582). The CPR regimen consisted of cyclophosphamide (CY) on days 1, 8, and 15, lenalidomide on days 1–21 and prednisone 100 mg q 2 days in a 28-day cycle. ASA 81 mg/day was given as DVT prophylaxis. Three dose levels were evaluated using a 3 × 3 dose escalation design. Thirty-two pts were entered between 11/2007-06/2009; median age was 64 (42-80) yrs, 60% were male, and immunoglobulin isotype was IgG in 19 (62%), IgA in 8 (25%) and light chain in 4 (13%) pts. Median β2-microglobulin level was 257 (92-767) nm/L, albumin 39 (34-48) g/L, creatinine 83 (50-126) μmol/L, platelet count 355 (75-479) × 109/L and ANC 2.5 (1.1-6.1) × 109/L. The median number of prior regimens was 2 (1-5). Prior therapy included: ASCT (single in 91%; double in 19%), thalidomide (28%) and bortezomib (50%). FISH cytogenetics were available in 13 pts; 1 had del 13q but none had t(4;14) or del p53. Table 1 summarizes protocol treatment delivered. Table 1. Dose level N Cyclophosphamide dose (mg/m2) Lenalidomide dose (mg) Prednisone dose (mg) Median # cycles given 1 3 150 15 100 12 (12–34+) 2 3 150 25 100 10 (9–23) 3 26 300 25 100 17 (5–28+) 1–3 (All) 32 150–300 15–25 100 19 (5–34+) Dose limiting toxicity was not observed during cycle 1 at any dose level. Grade 3–4 toxicities during the trial included: thrombocytopenia in 7 (22%) and neutropenia in 9 (29%), managed with dose reduction and/or growth factors; five episodes of febrile neutropenia occurred, all at dose level 3. In cohort 3, other grade 3–4 non-hematologic toxicities included 1 episode each of abdominal pain/bacteremia, hypokalemia, fatigue, sick sinus syndrome, cardiac amyloidosis, perforated diverticulum and 2 episodes of DVT. Two heavily pretreated pts developed 2° MDS, including 1 previously treated for lymphoma, 43 and 190 mos after the diagnosis of MM. The best response using modified EBMT criteria was documented at a median of 7 (1-26) cycles and included the following: dose level 1 (1 CR, 2 PR); dose level 2 (1 VGPR, 2 PR); dose level 3 (4 CR, 14 VGPR, 11 PR, 1 MR and 1 stable disease). At a median F/U of 16 (5-34) months, 13 pts remain on study and 18 have progressed at a median of 10 (2-23) mos; 1 was lost to F/U and 9 have died of progressive MM. The 1-year actuarial OS and PFS rates are 93% (95% CI 76–98%) and 78% (95% CI 60–89%), respectively. We conclude: 1) the combination of full doses of the agents in CPR can be given in a 28 day cycle with an acceptable safety profile; 2) the objective response rate (CR + PR + MR) in all 32 pts to date is 94%; 3) the 1-year OS of 93% and PFS of 78% compare favorably with other 3-drug combinations in rel/ref MM pts; 4) further evaluation of this regimen in newly diagnosed pts would be of interest. Disclosures: Reece: Celgene: Honoraria, Research Funding. Off Label Use: Combination of lenalidomide and cyclophosphamide and prednisone in relapsed and refractory myeloma patients. Chen:Celgene Corporation: Consultancy, Honoraria, Research Funding. Kukreti:Celgene: Honoraria.