Xu, Wei

Abstract p53 deletion by fluorescence in situ hybridization (FISH) has been reported in about 10% of newly diagnosed patients (pts) with multiple myeloma (MM) and has been associated with a poor prognosis. Previous data from our centre has demonstrated that the progression-free survival (PFS) and overall survival (OS) of these pts after a single autologous stem cell transplant (ASCT) is only 16.9 and 48.2 months, respectively, compared to 24.4 and 76.6 mos, respectively, in all pts transplanted during the same time period (Mikhael et al, Blood2007; 110: abstract 953). Minimal information is available on the treatment (Tx) and course of these pts following disease progression. Therefore, we performed a retrospective review of all MM pts treated at our institution who were found to have p53 deletion. We identified 31 pts with relapsed/refractory (rel/ref) MM with this cytogenetic abnormality. At diagnosis, median age was 54 years (range, 31–70), hemoglobin 97 g/L (range, 67–149), creatinine 96 μmol/L (range, 28–1751), beta 2-microglobulin 314 nmol/L (range, 225–437), CRP 3 mg/L (range, 2–7) and LDH 205 U/L (range, 82–478); 58% were male. Immunoglobulin subtypes included: IgG (14 pts), IgA (8 pts), IgD (2 pts) and light chain only (7 pts). Concomitant cytogenetic abnormalities included 13q deletion in 68% and t(4;14) in 67% of pts evaluable. Thirty-nine percent developed plasma cell leukemia (PCL) at some point in the disease course, which was associated with a poor OS (p=0.005). All but 5 had undergone prior ASCT with a median time from diagnosis to ASCT of 8 (95% CI, 4–145) mos. Txs given for rel/ref MM consisted of the following regimens: thalidomide-based in 15, bortezomib-based in 12, lenalidomide-based in 11, alkylating agents in 9 and steroids only in 5 pts, and other regimens (D-PACE or investigational drugs) in 7 pts. The median follow-up from diagnosis in these pts is 45 (95% CI, 4–145) mos. The overall response rate (≥PR) (ORR), median PFS and median OS from the start of each regimen is shown below. Agent Median duration of Tx (mos) ORR(%) Median PFS (mos) Median OS (mos) Thalidomide 6.2 20% 5.0 11.9 Bortezomib 5.2 50% 5.6 36.1 Lenalidomide 10.6 60% 4.8 36.1 Alkylating agents 6.0 11% 5.1 30.0 Steroids 1.9 20% 1.9 33.4 Other 2.2 43% 6.3 33.4 We conclude: 1) Median PFS in pts with the p53 deletion is less than 6 months, with an OS of 2.5–3 yrs; 2) novel agents other than thalidomide produce the highest ORR in rel/ref MM with p53 deletion; 3) the short OS in the thalidomide group is likely related to the unavailability of other novel agents for subsequent relapses, as the majority of the pts were treated before 2004; 4) better strategies/drugs are required for these pts.

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

Purpose The combination of oral weekly cyclophosphamide and alternate day prednisone is a convenient regimen for relapsed/refractory multiple myeloma (MM), and we sought to improve its efficacy by adding bortezomib, a proteasome inhibitor with proven antimyeloma activity. Patients and Methods We conducted a phase I-II trial evaluating six dose levels to define the maximum tolerated dose (MTD) of this combination in relapsed/refractory MM. An additional 10 patients were evaluated at the highest dose level reached. Results Thirty-seven patients were treated on this study. The MTD was not defined. Both of the highest dose levels of bortezomib tested (1.3 mg/m 2 on days 1, 4, 8, and 11 and 1.5 mg/m 2 on days 1, 8, and 15, each on a 28-day cycle) could be safely given with cyclophosphamide 300 mg/m 2 per week and prednisone. At these dose levels, the overall response rate was 95% (complete responses [CR] plus partial response plus minimal response), with CR observed in more than 50% of patients. The weekly bortezomib regimen resulted in fewer instances of grade 3 thrombocytopenia and grade 1 to 2 peripheral neuropathy; the 1-year progression-free and overall survival probabilities with this dose level were 83% (95% CI, 73% to 96%) and 100%, respectively. Conclusion Weekly bortezomib 1.5 mg/m 2 plus oral cyclophosphamide and prednisone produces an unprecedented response rate and encouraging 1-year survival in relapsed/refractory patients with MM. Further evaluation of this promising regimen is warranted both in relapsed and newly diagnosed disease.