Cure of myeloma: hype or reality?

Requirements for operational cure in multiple myeloma

Multiple myeloma is usually considered as an incurable disease. However, with the therapeutic improvement observed in the last few years, achievement of an "operational" cure is increasingly becoming a realistic goal. The advent of novel agents, with or without high-dose chemotherapy and autologous transplantation, uncovered a correlation between the depth of response to treatment and the outcome. Of note, minimal residual disease (MRD) negativity is increasingly shown to be associated with improved progression-free survival (PFS), and MRD status is becoming a well-established and strong prognostic factor. Here, we discuss the impact of MRD negativity on PFS and long-term disease control, as a surrogate for a potential cure in a significant proportion of patients. The MRD value and impact should be examined by focusing on different parameters: (i) sensitivity or lower limit of detection level (method used); (ii) timing of assessment and sustainability (iii) type and duration of treatment; (iv) initial prognostic factors (most importantly, cytogenetics) and (v) patient age. Currently, the highest probability of an operational cure is in younger patients receiving the most active drugs, in combination with autologous transplantation followed by maintenance therapy. Older patients are also likely to achieve operational cure, especially if they are treated upfront with an anti-CD38 antibody-based therapy, but also with novel immunotherapies in future protocols. The incorporation of MRD as a surrogate endpoint in clinical trials, would allow the shortening of these, leading to more personalised management, and achievement of long-term cure.

Long-term outcomes after autologous stem cell transplantation for multiple myeloma

As multiple myeloma (MM) treatments evolve, frequent updates are required to monitor the long-term effect of changes in approach. Traditionally, MM is considered an incurable disease, with most patients eventually relapsing. However, improvements in treatments has raised the possibility that MM might be functionally curable. To examine improvements in long-term survival, we followed 4329 patients with newly diagnosed MM treated with autologous stem cell transplantation (ASCT) at the University of Arkansas for Medical Sciences from 1989 through 2018. Overall survival (OS) and progression-free survival (PFS) were evaluated using Kaplan-Meier analysis, Cox proportional hazards models, relative survival analysis, and cure modeling among different time periods, risk groups, and demographic traits. Steady improvements in OS were found, with patients treated in 2014 or later having superior OS (hazard ratio, 0.35; 95% confidence interval [CI], 0.27-0.45) and reduced excess risk for MM death (relative excess risk, 0.30; 95% CI, 0.22-0.41) compared with patients treated in 1997 or earlier. Patients treated during intervening time periods often had intermediate survival, but trends in OS, PFS, and landmarked analyses were inconsistent. Cure models support the potential for cure, ranging from 6.3% to 31.3%, depending on the year of treatment, with 10.0% to 18.6% of patients achieving their normal life expectancy across multiple periods. There was some evidence of reductions in early mortality within 3 years of diagnosis, longer complete response (CR) duration, and reductions in relapse after achieving CR. However, results differed depending on age, risk group, and cytogenetic characteristics.

Curing myeloma at last: defining criteria and providing the evidence

Does the dogma that multiple myeloma is incurable still hold?. The genomic chaos and resulting resistance to apoptosis of myeloma, long considered an obstacle to cure, formed the basis of Total Therapy (TT) program. The TT approach uses all myeloma-active drugs upfront to target drug-resistant subclones during initial treatment to prevent later relapse. Long-term follow-up of 1202 patients (TT1: n = 231, median follow-up: 21 years; TT2: 668, median follow-up: 12 years; TT3a: n = 303, median follow-up: 9 years) permitted investigation of whether progression-free survival (PFS) and complete response (CR) duration were consistent with curability, ie observation of plateaus in Kaplan-Meier plots for PFS and CR duration. In the subset of 627 patients with plasma cell gene expression profiling data, cure plateaus were apparent at 5 years in the 14% with high-risk myeloma compared with 10 years in the remainder with low-risk disease. A parametric model based on PFS and CR duration supported an increase in curability: 10-year PFS and CR estimates increased from 8.8%/17.9% in TT1 to 15.5%/28.2% in TT2's control arm to 25.1%/35.6% in TT2's thalidomide arm and to 32.9%/48.8% in TT3a. Toward developing novel therapies, we recommend a concerted focus on patients with high-risk myeloma whose outcome has not been advanced.

European perspective on multiple myeloma treatment strategies in 2014

The treatment of multiple myeloma has undergone significant changes and has resulted in the achievement of molecular remissions, the prolongation of remission duration, and extended survival becoming realistic goals, with a cure being possible in a small but growing number of patients. In addition, nowadays it is possible to categorize patients more precisely into different risk groups, thus allowing the evaluation of therapies in different settings and enabling a better comparison of results across trials. Here, we review the evidence from clinical studies, which forms the basis for our recommendations for the management of patients with myeloma. Treatment approaches depend on "fitness," with chronological age still being an important discriminator for selecting therapy. In younger, fit patients, a short three drug-based induction treatment followed by autologous stem cell transplantation (ASCT) remains the preferred option. Consolidation and maintenance therapy are attractive strategies not yet approved by the European Medicines Agency, and a decision regarding post-ASCT therapy should only be made after detailed discussion of the pros and cons with the individual patient. Two- and three-drug combinations are recommended for patients not eligible for transplantation. Treatment should be administered for at least nine cycles, although different durations of initial therapy have only rarely been compared so far. Comorbidity and frailty should be thoroughly assessed in elderly patients, and treatment must be adapted to individual needs, carefully selecting appropriate drugs and doses. A substantial number of new drugs and novel drug classes in early clinical development have shown promising activity. Their introduction into clinical practice will most likely further improve treatment results.

The emerging role of carfilzomib combination therapy in the management of multiple myeloma

Carfilzomib is a proteasome inhibitor that selectively and irreversibly binds to its target, resulting in sustained inhibition absent of off-target effects relative to bortezomib. Single-agent carfilzomib has produced robust and durable responses in clinical trials and it has been approved in the US for treating relapsed and refractory multiple myeloma (MM). Due to its favorable safety profile, carfilzomib is particularly suitable for use in combination strategies. Promising data have been reported from studies that investigated the use of carfilzomib in combination with immunomodulators, alkylating agents, glucocorticoids, histone deacetylase inhibitors and kinesin spindle protein inhibitors. Ongoing pivotal randomized Phase III studies are investigating the efficacy and safety of carfilzomib combinations in patients with relapsed MM and transplant ineligible patients.

Nab-paclitaxel for breast cancer: a new formulation with an improved safety profile and greater efficacy

Taxanes, paclitaxel and docetaxel, are among the most effective agents used to treat breast cancer. Nab-paclitaxel (ABI-007, Abraxane) is paclitaxel encapsulated in albumin. This differs from the more conventional formulation which uses cremophor to increase the solubility of paclitaxel (CrEL-paclitaxel). In a randomized trial that formed the basis of its regulatory approval in the USA, 3-weekly nab-paclitaxel induced a higher response rate and longer time to progression than CrEL-paclitaxel in patients with metastatic breast cancer. Except for grade 3 sensory neuropathy, nab-paclitaxel was also safer. An interim analysis from a more recent randomized Phase II trial suggests that weekly nab-paclitaxel is more effective and safer than either 3-weekly nab-paclitaxel or 3-weekly docetaxel. The superior efficacy of nab-paclitaxel is presumably due to the improved safety profile, which allows for the administration of higher doses, a greater proportion of which actually reaches the tumor. Observations on the development of nab-paclitaxel have important implications for our understanding of dose response in the use of cytotoxic drugs to treat all forms of cancer. Although it is not yet clear whether nab-paclitaxel can be routinely substituted for CrEL-paclitaxel or docetaxel in breast cancer treatment regimens, it seems highly likely that this will occur within the next 5 years.

Role of allogeneic stem cell transplantation in multiple myeloma

Multiple myeloma is currently incurable using standard treatment regimens. While the introduction of high-dose chemotherapy with autologous stem cell rescue has been shown to increase overall survival when compared with chemotherapy alone, this strategy is palliative. Allogeneic stem cell transplantation provides the potential for long-term disease-free survival in a small proportion of patients, although its application has been limited by procedure-related mortality, reflecting the intensive myeloablative conditioning given. Recently, reduced intensity conditioning regimens have been developed in an attempt to reduce toxicity whilst preserving the allogeneic graft-versus-myeloma effect, therefore maintaining the potential for disease eradication. This review aims to examine the current position of allogeneic transplantation in the management of myeloma.

A population-based analysis of the effect of autologous hematopoietic cell transplant in the treatment of multiple myeloma

This population registry-based study followed all cases of myeloma diagnosed in New South Wales, Australia, during 2002-2005 and compared survival outcomes of those who proceeded to autologous hematopoietic cell transplant (HCT) with those who did not. Data available consisted of demographic details and survival, and did not include disease details or treatment type or response. Of 708 patients, 270 (38%) had a HCT. The 5-year overall survival (OS) of HCT recipients was significantly better than for those who did not proceed to HCT (62% vs. 54%, p = 0.003). HCT was a significant favorable risk factor for OS, while age over 60 was an adverse risk factor. However, for patients alive at 1 year from diagnosis, there was no significant difference in survival between HCT and non-HCT patients, suggesting that worse disease biology and/or coexisting morbidities were likely to be major reasons for the poorer outcome for non-HCT patients.

Curability of multiple myeloma

Among 792 patients with multiple myeloma treated from 1987 to 2010 and assessed after 18 months, there were 167 patients with complete remission. For those 60 patients treated between 1987–1998 and with long followup, the latest relapse occurred after 11.8 years, so that 13 patients have remained in sustained complete remission for longer than 12 years (range 12–22 years). These results suggest that 3% of all patients treated during that period may be cured of multiple myeloma. In addition to immunofixation, more sensitive techniques for the detection of residual disease should be applied more consistently in patients with apparent complete remission in order to identify those with potential cure.

European perspective on multiple myeloma treatment strategies: update following recent congresses

The management of multiple myeloma has undergone profound changes over the recent past as a result of advances in our understanding of the disease biology as well as improvements in treatment and supportive care strategies. Notably, recent years have seen a surge in studies incorporating the novel agents thalidomide, bortezomib, and lenalidomide into treatment for different disease stages and across different patient groups. This article presents an update to a previous review of European treatment practices and is based on discussions during an expert meeting that was convened to review novel agent data published or presented at medical meetings until the end of 2011 and to assess their impact on treatment strategies.

The concentration of CD44 is increased in hematopoietic stem cell grafts of patients with acute myeloid leukemia, plasma cell myeloma, and non-Hodgkin lymphoma

CONTEXT

In autologous hematopoietic stem cell transplantation (autoHSCT), malignant cells remaining in the graft may re-engraft leading to relapse of the original disease. CD44 is known to play a role in the engraftment of leukemia-initiating cells and is shed from the surface of malignant cells. Soluble CD44 is a cleaved fragment, which is found in the serum of patients with metastasized epithelial and hematologic malignancies and in some other cancers, and has been demonstrated to be correlated with clinical outcome.

OBJECTIVES

To investigate (1) a possible correlation between the concentration of CD44 in an autoHSCT graft and the type of hematologic malignancy and (2) a possible correlation between the concentration of CD44 in the autoHSCT graft with clinical outcome after autoHSCT.

DESIGN

We measured CD44 in 157 hematopoietic stem cell grafts from patients with hematologic malignancies and from 43 healthy donors by enzyme-linked immunosorbent assay.

RESULTS

Levels of CD44 were almost 2-fold higher in the patients' grafts. Highest levels were found in the grafts of patients with acute myeloid leukemia, diffuse large B-cell lymphoma, and plasma cell myeloma, congruent with known CD44 expression levels in these malignancies. The survival advantage among patients with CD44 levels less than 22 000 ng/mL was highly statistically significant.

CONCLUSION

These results show that CD44 levels in an autoHSCT graft may be linked to clinical outcome after autoHSCT.

Achievement of at least very good partial response is a simple and robust prognostic factor in patients with multiple myeloma treated with high-dose therapy: long-term analysis of the IFM 99-02 and 99-04 Trials

PURPOSE

The prognostic impact of complete response (CR) achievement in multiple myeloma (MM) has been shown mostly in the context of autologous stem-cell transplantation. Other levels of response have been defined because, even with high-dose therapy, CR is a relatively rare event. The purpose of this study was to analyze the prognostic impact of very good partial response (VGPR) in patients treated with high-dose therapy.

PATIENTS AND METHODS

All patients were included in the Intergroupe Francophone du Myelome 99-02 and 99-04 trials and treated with vincristine, doxorubicin, and dexamethasone (VAD) induction therapy followed by double autologous stem-cell transplantation (ASCT). Best post-ASCT response assessment was available for 802 patients.

RESULTS

With a median follow-up of 67 months, median event-free survival (EFS) and 5-year EFS were 42 months and 34%, respectively, for 405 patients who achieved at least VGPR after ASCT versus 32 months and 26% in 288 patients who achieved only partial remission (P = .005). Five-year overall survival (OS) was significantly superior in patients achieving at least VGPR (74% v 61% P = .0017). In multivariate analysis, achievement of less than VGPR was an independent factor predicting shorter EFS and OS. Response to VAD had no impact on EFS and OS. The impact of VGPR achievement on EFS and OS was significant in patients with International Staging System stages 2 to 3 and for patients with poor-risk cytogenetics t(4;14) or del(17p).

CONCLUSION

In the context of ASCT, achievement of at least VGPR is a simple prognostic factor that has importance in intermediate and high-risk MM and can be informative in more patients than CR.

Complete remission in multiple myeloma examined as time-dependent variable in terms of both onset and duration in Total Therapy protocols

Landmark analyses are used to investigate the importance for survival of achieving complete response (CR), an important initial goal of myeloma therapy. With median times to CR in Total Therapy (TT) trials of approximately 1 year, this approach excludes a sizeable fraction of patients dying before such a landmark. To permit inclusion of all trial participants, we investigated the prognostic implications of both onset and duration of CR as time-dependent variables. Superseding the adverse effects of cytogenetic abnormalities and other standard prognostic parameters, both failure to achieve CR (non-CR) and, especially, loss of CR (los-CR) were independently associated with inferior survival in TT1, TT2, and TT3 protocols. In the context of gene array-defined risk, available in TT2 and TT3 subsets, both los-CR and non-CR terms were retained in the survival model as dominant adverse variables, stressing the prognostic importance of sustaining CR status, especially in high-risk disease.

A Phase II trial of autologous stem cell transplantation followed by mini-allogeneic stem cell transplantation for the treatment of multiple myeloma: an analysis of Eastern Cooperative Oncology Group ECOG E4A98 and E1A97

Conventional allogeneic hematopoietic stem cell transplantation (HSCT) for multiple myeloma is associated with high transplantation-related mortality (TRM). Nonmyeloablative allogeneic transplantation (NST) uses the well-known graft-versus-myeloma (GVM) effect to eradicate minimal residual disease. The Eastern Cooperative Oncology Group conducted a Phase II trial of autologous HSCT followed by NST to provide maximal tumor cytoreduction to allow for a subsequent GVM effect. Patients received melphalan 200 mg/m(2) with autologous HSCT, followed by fludarabine 30 mg/m(2) in 5 daily doses and cyclophosphamide 1 g/m(2) in 2 daily doses with matched sibling donor NST. Graft-versus-host disease (GVHD) prophylaxis included cyclosporine and corticosteroids. The primary endpoints were TRM, graft failure, acute GVHD, progression-free survival (PFS), and overall survival (OS). Thirty-two patients were enrolled into the study; 23 patients completed both transplantations (72%). Best responses post-NST were 7 (30%) complete remission (CR), 11 (48%) partial remission (PR), 2 (9%) no response, and 3 (13%) not evaluable. Acute grade III-IV GVHD was observed in 4 patients (17%), and chronic GVHD was seen in 13 patients (57%; 7 limited, 6 extensive). Chronic GVHD resulted in the following responses: 3 (23%) CR, 1 continuing CR, and 6 (46%) PR. Two patients (8.7%) had early TRM. With a median follow up of 4.6 years, the median PFS was 3.6 years, and the 2-year OS was 78%. Our findings indicate that autologous HSCT followed by NST is feasible, with a low early TRM in a cooperative group setting. The overall response rate was 78%, including 30% CR, similar to other reports for autologous HSCT-NST. Because a plateau in PFS or OS was not observed with this treatment approach even in patients achieving CR, we suggest that future studies use posttransplantation maintenance therapy.

Benefit of complete response in multiple myeloma limited to high-risk subgroup identified by gene expression profiling

EXPERIMENTAL DESIGN

To determine whether the clinical benefit of complete remission (CR) may depend on prognostic subgroups of patients with multiple myeloma.

PATIENTS AND METHODS

Newly diagnosed patients with myeloma received a tandem autotransplant regimen. Using multivariate regression analyses, we examined the prognostic implications of time-dependent onset of CR on overall survival and event-free survival in the context of standard prognostic factors (SPF) and gene expression profiling-derived data available for 326 patients.

RESULTS

CR benefited patients regardless of risk status when only SPFs were examined. With knowledge of gene array data, a survival (and event-free survival) benefit of CR only pertained to the small high-risk subgroup of 13% of patients (hazard ratio, 0.23; P = 0.001), whereas the majority of patients with low-risk disease had similar survival expectations whether or not CR was achieved (hazard ratio, 0.68; P = 0.128).

CONCLUSIONS

Access to gene expression information permitted the recognition of a small very high-risk subgroup of 13% of patients, in whom prolonged survival critically depended on achieving CR. Absence of such benefit in the remainder should lead to a reassessment of clinical trial designs that rely on this end point as a surrogate for long-term prognosis.

Bortezomib down-regulates the cell-surface expression of HLA class I and enhances natural killer cell-mediated lysis of myeloma

Human leukocyte antigen class I molecules expressed by tumor cells play a central role in the regulation of natural killer (NK) cell-mediated immune responses. The proteasome inhibitor bortezomib has demonstrated significant activity in multiple myeloma (MM). We hypothesized that treatment of MM with bortezomib results in the reduction of cell-surface expression of class I and thereby sensitizes MM to NK cell-mediated lysis. Here we report that bortezomib down-regulates class I in a time- and dose-dependent fashion on all MM cell lines and patient MM cells tested. Downregulation of class I can also be induced in vivo after a single dose of 1.0 mg/m(2) bortezomib. Bortezomib significantly enhances the sensitivity of patient myeloma to allogeneic and autologous NK cell-mediated lysis. Further, the level of decrease in class I expression correlates with increased susceptibility to lysis by NK cells. Clinically relevant bortezomib concentrations do not affect NK-cell function. Our findings have clear therapeutic implications for MM and other NK cell-sensitive malignancies in the context of both allogeneic and autologous adoptively transferred NK cells.

Antibody targeting of the insulin-like growth factor I receptor enhances the anti-tumor response of multiple myeloma to chemotherapy through inhibition of tumor proliferation and angiogenesis

Although many multiple myeloma (MM) patients initially respond to cytotoxic therapy, most eventually relapse. Novel therapeutic strategies employing a combination of chemotherapy with targeted biologics may significantly enhance the response of tumor cells to treatment. We tested a fully human anti-IGF-IR antibody (A12) against MM, and showed specific inhibition of IGF-I or serum-induced IGF-IR signaling in MM cells in vitro. The A12 as a single agent was demonstrated to exert modest to significant inhibition of tumor growth in vivo in various subcutaneous xenograft MM models. The A12 was also evaluated in a disseminated xenograft MM.1S NOD/SCID model as monotherapy or in combination with other drugs (bortezomib, melphalan) currently in clinical use. The tumor burden, as determined by luciferase bioimaging, was sharply decreased, and overall survival significantly prolonged when the therapies were combined. Immunohistochemical analysis demonstrated that the A12 treated tumors had significantly decreased vascularization compared to control tumors. Furthermore, most MM lines constitutively secreted significant quantities of VEGF, and this was enhanced following IGF-I treatment. Inhibition of IGF-IR by the A12 in vitro suppressed both constitutive and IGF-I-induced secretion of VEGF, indicating that a putative anti-angiogenic mechanism associated with the A12 treatment may contribute to its anti-tumor effect.

Nonmyeloablative unrelated donor hematopoietic cell transplantation to treat patients with poor-risk, relapsed, or refractory multiple myeloma

The purpose of this study was to determine long-term outcome of unrelated donor nonmyeloablative hematopoietic cell transplantation (HCT) in patients with poor-risk multiple myeloma. A total of 24 patients were enrolled; 17 patients (71%) had chemotherapy-refractory disease, and 14 (58%) experienced disease relapse or progression after previous autologous transplantation. Thirteen patients underwent planned autologous transplantation followed 43-135 days later with unrelated transplantation, whereas 11 proceeded directly to unrelated transplantation. All 24 patients were treated with fludarabine (90 mg/m(2)) and 2 Gy of total body irradiation before HLA-matched unrelated peripheral blood stem cell transplantation. Postgrafting immunosuppression consisted of cyclosporine and mycophenolate mofetil. The median follow-up was 3 years after allografting. One patient experienced nonfatal graft rejection. The incidences of acute grades II and III and chronic graft-versus-host disease were 54%, 13%, and 75%, respectively. The 3-year nonrelapse mortality (NRM) was 21%. Complete responses were observed in 10 patients (42%); partial responses, in 4 (17%). At 3 years, overall survival (OS) and progression-free survival (PFS) rates were 61% and 33%, respectively. Patients receiving tandem autologous-unrelated transplantation had superior OS and PFS (77% and 51%) compared with patients proceeding directly to unrelated donor transplantation (44% and 11%) (PFS P value = .03). In summary, for patients with poor-risk, relapsed, or refractory multiple myeloma, cytoreductive autologous HCT followed by nonmyeloablative conditioning and unrelated HCT is an effective treatment approach, with low NRM, high complete remission rates, and prolonged disease-free survival.

Autologous peripheral blood stem cell transplantation in multiple myeloma using oral versus I.V. melphalan

Autologous peripheral blood stem cell transplantation is the therapy of choice for the treatment of multiple myeloma (MM) patients younger than 70 years old. Between August 1993 and November 2004, 54 patients with MM were autografted after conditioning with high-dose oral melphalan 140 mg/m(2) in combination with etoposide and carmustine (28 patients) or with high-dose melphalan 200 mg/m(2) I.V. (26 patients). The oral and IV melphalan groups were comparable. There were no significant differences in disease-free survival (DFS) and overall survival (OS) between the groups; however, in patients transplanted in remission, OS and DFS were better in the I.V. melphalan group. Four good-prognostic factors were identified: interval between diagnosis and transplant <18 months, number of prior chemotherapy lines < or =2, remission status (complete or partial), and the use of I.V. melphalan. In conclusion, I.V. melphalan is the therapy of choice for conditioning patients with MM who are in remission.

NY-ESO-1 immunotherapy for multiple myeloma

Most patients with poor-prognosis myeloma (abnormal metaphase cytogenetics) achieve excellent responses with tandem transplants, but the remissions are not durable. Novel interventions such as immunotherapy may eradicate the residual chemotherapy-resistant disease. Immunotherapy targeting weak antigens such as myeloma idiotype or tumor lysate has failed to produce clinically meaningful responses. We previously reported that the NY-ESO-1 antigen is expressed in >60% of poor-prognosis myeloma at diagnosis. Since NY-ESO-1 is highly immunogenic and is not expressed in most normal tissues, it is an ideal target for anti-myeloma immunotherapy. NY-ESO-1 based therapies are already being tested in clinical trials for a multitude of tumors. This review discusses the potential of NY-ESO-1 immunotherapy to improve outcome for myeloma.

Cure of multiple myeloma -- more hype, less reality

Randomized studies have firmly established the role of autologous transplant as initial therapy in multiple myeloma (MM). Indeed, MM has emerged as the commonest indication for autologous SCT in North America. The conceptual basis for high-dose therapy is the goal of complete remission (CR) through steep reduction in tumor burden affected by single and tandem transplants. Careful analysis of the data challenges the notion of CR as a surrogate to success. Intrinsically aggressive MM, defined by known unfavorable biologic risk factors, overrides the benefit of CR. In contrast, subgroups of patients with favorable biological risk factors may achieve prolonged survival, often without ever achieving CR. Unfortunately, even with tandem transplants, there is no plateau in survival curves. To this end, sequential autologous followed by nonmyeloablative allotransplants are a novel attempt at 'curing' myeloma, but the results thus far have failed to show a definite plateau in survival. Given the improvements in supportive care and concomitant reduction in transplant-related mortality, conventional myeloablative allogeneic transplants need to be re-examined as an option in high-risk aggressive myeloma. At the same time, novel antimyeloma therapies, newer risk stratification and staging tools are transforming the treatment algorithm. We examine the changing role of transplantation in myeloma in the context of novel drug therapy, biologic risk stratification and improving supportive care while arguing that the current 'one size fits all' transplant approaches are far from a cure.

Standard chemotherapy compared with high-dose chemoradiotherapy for multiple myeloma: final results of phase III US Intergroup Trial S9321

PURPOSE

Results of a prospective randomized trial conducted by the Intergroupe Francais du Myélome (IFM 90) indicated that autologous hematopoietic cell-supported high-dose therapy (HDT) effected higher complete response rates and extended progression-free survival (PFS) and overall survival (OS) compared with standard-dose therapies (SDT) for patients with multiple myeloma (MM).

PATIENTS AND METHODS

In 1993, three North American cooperative groups launched a prospective randomized trial (S9321) comparing HDT (melphalan [MEL] 140 mg/m2 plus total-body irradiation 12 Gy) with SDT using the vincristine, carmustine, MEL, cyclophosphamide, and prednisone regimen. Responders on both arms (> or = 75%) were randomly assigned to interferon (IFN) or no maintenance treatment.

RESULTS

With a median follow-up time of 76 months, no differences were observed in response rates between the two study arms (HDT, n = 261 patients; SDT, n = 255 patients). Similarly, PFS and OS durations did not differ between the HDT and SDT arms, with 7-year estimates of PFS of 17% and 16%, respectively, and OS of 37% and 42%, respectively. Of 242 patients achieving at least 75% tumor reduction, no difference was observed in PFS or OS among the 121 patients randomly assigned to IFN and the 121 patients randomly assigned to no maintenance therapy. Among 157 patients relapsing on SDT, 87 received a salvage autotransplantation; their median survival time of 30 months was only slightly better than the survival time of the remaining patients who were managed with further SDT (23 months; P = .13).

CONCLUSION

The HDT and SDT regimens used in S9321 yielded comparable response rates and PFS and OS durations. IFN maintenance therapy did not benefit patients who achieved > or = 75% tumor reduction on either arm.