Search

In the presence of effective treatment options for systemic light chain (AL) amyloidosis, autologous stem cell transplantation (ASCT) is sometimes deferred after stem cell collection. We designed this retrospective study to compare overall survival (OS) between patients who proceed directly to ASCT after stem cell collection and those who defer ASCT. We included patients with AL amyloidosis who had stem cell collection at Mayo Clinic, Minnesota, from 2004 to 2018. ASCT was considered "early" if performed within 90 days of collection, and "deferred" if performed after 90 days, or not done by last follow up. We included 651 patients; 527 underwent early ASCT and 124 deferred ASCT. There was no difference in OS with early vs. deferred ASCT (median OS: 13.0 vs. 11.4 years, respectively, P = 0.28). There was no difference in OS between the 2 groups among patients with early or advanced Mayo Stage. Among patients who achieved ≥very good partial response at the time of collection, OS in the early and deferred groups was 14.2 and 13.4 years, respectively (P = 0.06). Survival outcomes are similar with early and deferred ASCT. Further studies are needed to identify patients who would benefit from each approach.

Over the last two decades, the utilization of various novel therapies in the upfront or salvage settings has continued to improve survival outcomes for patients with Multiple Myeloma (MM). Thus, the conventional role for hematopoietic stem cell transplantation (HSCT) in MM either in the form of an autologous stem cell transplant (ASCT) or an allogeneic stem cell transplant (Allo-SCT) warrants re-evaluation, given the aforementioned clinical advances. Here, we present a consensus statement of our multidisciplinary group of over 30 Mayo Clinic physicians with a special interest in the care of patients with MM and provide evidence-based recommendations on the use of HSCT in MM. We specifically address topics that include the role and timing of an ASCT for MM in the era of novel agents, eligibility for an ASCT, post-ASCT consolidation, and maintenance options, and finally the utility of an upfront tandem ASCT, salvage second ASCT, and an allo-SCT in MM.

Use of melphalan in multiple myeloma was observed to have a deleterious effect on stem cell collection in older studies. There is limited data on the impact of melphalan in light chain (AL) amyloidosis, especially in the plerixafor era. We retrospectively evaluated stem cell mobilization in 610 patients with AL amyloidosis, of which 79 had prior exposure to melphalan, 167 to other chemotherapeutics, while 364 had no chemotherapy exposure. Collection of CD34+ stem cells × 10 6 /kg was lower in the melphalan group. Median total yields in the melphalan, non-melphalan, and no chemotherapy groups were 5.5, 7.7, and 7.8, respectively; p < 0.001. Day-1 yields were 2.7, 3.5, and 4.0 (p = 0.0003), respectively, and median yields per collection were 2.0, 3.3, and 4.0 (p < 0.001), respectively. Similar results were observed in the sub-group analysis after plerixafor was integrated in our collection algorithm (2009). Patients in the melphalan group had higher failure rate of 9% vs. 2% each in the other two groups (p = 0.006). Impact of melphalan was dose-dependent, with cumulative melphalan exposure of >150 mg (median: three cycles) resulting in lower yields. Therefore, duration of melphalan exposure prior to stem cell collection should be limited, ideally, not exceeding more than two cycles of treatment.

Autologous stem cell transplant (Auto-SCT) is increasingly used in older patients with multiple myeloma (MM), despite lack of phase 3 trials in this age-defined population. For 207 consecutive MM patients who underwent Auto-SCT and were 70 years or older at transplant (study cohort), data were analyzed and compared with a younger cohort (1764 Auto-SCT patients <70 years old). The proportion of Auto-SCT in the older patients increased from 7.8% of all transplants in 1998-2006 to 12.9% in 2007-2015. Sixty percent of patients required stem cell mobilization with chemotherapy or plerixafor. Full-dose melphalan conditioning was given to 55% of the older patients compared with 93% of the younger patients (P<0.001). Older patients were more likely to be hospitalized (64% vs 55%; P=0.01), but hospitalization duration was comparable. For newly diagnosed patients, median PFS was 33.5 months for the older cohort and 33.8 months for the younger cohort (P=0.91), and median overall survival was 6.1 and 7.8 years, respectively (P=0.11). Presumably, a smaller fraction of patients, age 70-76, is selected for Auto-SCT, but the benefits are comparable to those seen for younger patients. Reduced-dose melphalan was given to approximately half the patients to avoid excessive toxicity.

Plasma cell myeloma, characterized by clonally aberrant plasma cells that produce abnormal monoclonal Igs, is the most common indication for autologous hematopoietic progenitor cell transplantation (AHPCT) in North America. We observed appearance of new monoclonal gammopathies different from the original protein in the post-AHPCT setting and termed this condition 'secondary MGUS' (monoclonal gammopathy of undetermined significance). Hence, we performed a retrospective, single institution review of serum protein electrophoresis/immunofixation electrophoresis data in 92 AHPCT recipients from the period 2000-2009. In all, 22 of 92 patients (24%) undergoing AHPCT met criteria for secondary MGUS. Contrary to previous studies, often referred to as 'abnormal protein banding,' we did not observe this condition as a favorable prognostic indicator in affected patients when compared with the control group (P=0.686). However, we did note that a subgroup of the study cohort who developed secondary MGUS after a prolonged latency (>10 months) had an improved median OS compared with the remainder of the study cohort (75 months vs 41 months, P=0.005). As there have been significant advancements in understanding the pathobiology and clinical significance of MGUS, we believe that secondary MGUS merits dedication of resources for investigation to determine its true clinical relevance, prognostic value and pathophysiology.

Auto-SCT is an effective therapy for patients with multiple myeloma (MM), but nearly a fifth of these patients relapse within a year of auto-SCT. We studied 494 patients, undergoing auto-SCT within 12 months of diagnosis of MM. Patients were divided into two groups: early relapse (relapse 12 months after auto-SCT or disease free at the last follow up). One hundred twenty patients (24%) were in the early relapse and 374 (76%) were in the late-relapse groups. The early relapse group had a significantly shorter median overall survival (OS) from diagnosis (26.6 vs 90.7 months; P<0.001) and from auto-SCT (20.1 vs 82.5 months; P<0.001). Among the 345 patients who have relapsed after auto-SCT, median OS from relapse was 10.8 months in the early relapse group compared to 41.8 months for the rest (P<0.001) and was longer with increasing duration of response to the SCT. In multivariate analyses, labeling index >or=1% at transplant, greater than one treatment regimen prior to auto-SCT, and failure to achieve a complete response were predictive of early relapse. Patients who relapse within 12 months of an auto-SCT have a poor outcome and should be offered trials evaluating novel treatment approaches.

Reported results of high-dose therapy (HDT) reflect the combined effect of initial therapy and HDT. The incremental contribution of HDT is often difficult to analyze with varying degrees of response pre-HDT. Here we analyze results of HDT in patients with measurable disease at transplant, defined as a serum or 24 h urine M protein of >1.0 g per 100 ml and >200 mg per day, respectively. Paraprotein responses were calculated using measurements prior to HDT and the lowest subsequent measurement. A total of 431 patients were studied; 264 (61.3%) transplanted within 1-year of diagnosis. An additional reduction in paraprotein by 50% following HDT was seen in 86% patients; with 129 patients (30%) obtaining a 90% reduction. Patients with at least a 90% reduction had longer time to progression with no overall survival advantage and this was independent of other prognostic factors for decreased risk of progression. This study provides an estimate of the degree of tumor reduction provided by HDT, in addition to that provided by the initial therapy. In this group of patients with measurable disease after initial therapy, HDT therapy leads to complete responses in nearly a quarter of the patients and a 90% reduction in another 7%, an outcome associated with better progression-free survival.

Autologous SCT (ASCT) remains an effective therapy for eligible patients with myeloma. Previous studies have suggested a lack of impact of the initial therapy on the outcome after ASCT. It is not clear if incorporation of new agents in the initial treatment regimens will have any impact on the outcome after ASCT. We studied 472 patients undergoing ASCT within 12 months of diagnosis to assess the effect of initial therapy on the outcome after ASCT. Patients received initial therapy with vincristine, adriamycin and dexamethasone (VAD), dexamethasone, thalidomide and dexamethasone or lenalidomide and dexamethasone. While patients treated with dexamethasone alone had higher disease burden at ASCT, no differences were observed in the response rates to ASCT, post transplant complications or treatment-related mortality among the groups. The median time to progression after ASCT was 27.1, 24.7, 21.1 months and did not reach the VAD, Dex, Thal-Dex and Len-Dex group, respectively, P=0.11. The median overall survival from ASCT was 62 months for VAD, 69.6 months for Dex and were not reached for Thal-Dex and Len-Dex groups, P=0.2. For patients undergoing early ASCT for myeloma, the nature of initial treatment utilized has no long-term impact on the outcome of ASCT.

Given the survival advantage, high-dose therapy (HDT) remains the standard of care for patients with multiple myeloma eligible for the procedure. For those undergoing HDT, initial therapy aimed at reducing tumor burden is given prior to stem cell harvest. Various regimens, mostly variations of VAD (vincristine, doxorubicin, dexamethasone), are used for induction therapy. We retrospectively evaluated if single agent dexamethasone would be an effective induction therapy, given that it is the most active drug in these combinations. A total of 35 patients who received induction therapy with dexamethasone alone were compared to a similar group of 72 patients who received VAD as the initial therapy. We found a 63% response rate with dexamethasone compared to 74% with VAD (P=0.25). Including minimal responses, the overall response rate for Dex and VAD was 74 and 86%, respectively (P=0.13). The overall and complete response rates to transplant, respectively, were 97 and 26% for the dexamethasone group and 100 and 39% for the VAD group; P=0.33 and 0.18. No significant differences were observed in the progression-free and overall survival at 1 year post transplant. Single agent dexamethasone appears to be an effective alternative to VAD for induction therapy prior to HDT in myeloma.

Bone marrow (BM) angiogenesis is increased in multiple myeloma and is an important prognostic factor. However, prior studies were mainly done on patients receiving conventional chemotherapy and there is limited data on its prognostic value in patients undergoing high-dose therapy (HDT) as initial therapy. We studied BM angiogenesis in terms of microvessel density (MVD) in 88 newly diagnosed patients, who were uniformly treated, with 3-4 cycles of induction chemotherapy followed by HDT. We examined if MVD at diagnosis was predictive of response to induction therapy or to subsequent HDT. In addition, we also examined its prognostic value in these patients. The median MVD for primary refractory patients was 28 (range, 2-84) compared to 27 (range, 2-99) for responding patients (P=0.7). The median progression-free survival (PFS) was 21 months for those with high-grade angiogenesis compared to 42 months for those with low-grade angiogenesis, P=0.017. The median overall-survival (OS) from diagnosis was 40 months for those with high-grade angiogenesis and not yet reached, for those with low-grade angiogenesis, P=0.007. BM MVD at the time of initial diagnosis is an important prognostic factor for OS and PFS in patients undergoing autologous transplantation as frontline therapy for myeloma.

Autologous stem cell transplant (SCT) improves survival in multiple myeloma (MM) and remains the standard of care for eligible patients. Nearly a third of patients with newly diagnosed MM fail initial therapy aimed at reducing tumor burden preceding SCT (primary refractory). It is unclear if an initial response is important for successful SCT. We evaluated our experience with SCT in 50 patients with primary refractory MM and compared it to 101 patients with chemosensitive disease receiving SCT. The study cohort had a median age of 56 years (range 29-72) consisting of 87 males (58%). A total of 46 patients (92%) in the refractory group and 100 (99%) in the chemosensitive group had a response to transplant (50% or greater reduction in the M-protein). In all, 10 refractory patients (20%) and 35 (35%) in the chemosensitive group achieved a CR (P=0.06). The 1-year estimated progression-free survival from the time of transplant for the refractory group was 70% compared to 83% for the chemosensitive group (P=0.65). The lack of response to initial induction therapy does not appear to preclude a good response to SCT. We recommend that patients with primary refractory MM be offered early SCT.

Increased bone marrow angiogenesis is a poor prognostic marker in patients with chronic myelogenous leukemia (CML). Allogeneic stem cell transplantation (ASCT) can be curative for patients with CML. Studies in myeloma have shown persistent increased bone marrow microvessel density (MVD) after autologous transplantation. It is not clear if abnormal bone marrow angiogenesis persists following a curative intervention like allogeneic transplantation. We evaluated MVD from bone marrow samples obtained just prior to and at 3-5 months after ASCT in 24 patients with CML. The median MVD pre-transplant was 14 (4-37), with 11 patients having high-grade angiogenesis and 13 having low grade. The median post transplant MVD was 20 (range 5-36), with 12 patients having high-grade angiogenesis and 12 low grade. The median time between biopsies was 4 months (range 1-6 months). The microvessels in the post transplant bone marrow appeared morphologically different with striking dilatation and sinusoidal appearance compared to the pre-transplant marrow. However, there was no significant change in MVD following transplant (P=0.8, paired t-test). Abnormal bone marrow angiogenesis appears to persist in the bone marrow following ASCT for CML, at least in the short term.

The purpose of this study was to determine the effect of thalidomide on stem cell collection and engraftment in patients with multiple myeloma. We performed a retrospective review of 67 patients newly diagnosed with multiple myeloma at Mayo Clinic and treated with a single regimen prior to stem cell transplantation between January of 2000 and September of 2001. Stem cells were collected from 24 patients who received thalidomide, 200 mg/day, with dexamethasone as initial therapy before stem cell collection. These patients were compared with 43 control patients seen during the same period who had received only one previous regimen before stem cell collection and transplantation. The cumulative thalidomide dose before stem cell collection was 17 000 mg over a median of four cycles (range, 2-7 cycles). The thalidomide and control groups were not significantly different in their baseline characteristics, number of stem cells collected, time to collection, or time to engraftment of neutrophils or platelet count of 50 000/microl. Time to platelet count of 20 000/microl was delayed by a median of 4 days (P=0.008), but platelet transfusion requirements did not differ (P=0.95). We concluded that thalidomide does not substantially affect peripheral cell mobilization or engraftment.