Multiple myeloma treated with high dose intravenous melphalan

The emerging role of melflufen and peptide-conjugates in multiple myeloma

PURPOSE OF REVIEW

The past two decades have witnessed an impressive expansion in the treatment landscape of multiple myeloma, leading to significant improvements in progression-free; as well as overall survival. However, almost all patients still experience multiple relapses during their disease course, with biological and cytogenetic heterogeneity affecting response to subsequent treatments. The purpose of this review is to provide a historical background regarding the role of alkylating agents and an updated data regarding the use of peptide-drug conjugates such as melflufen for patients with multiple myeloma.

RECENT FINDINGS

The combination of daratumumab-melflufen-dexamethasone evaluated in the LIGHTHOUSE study showed a statistically significant improvement in progression-free survival compared to single-agent daratumumab (not reached vs. 4.9 months respectively; P  = 0.0032), with improvement in overall response rate to 59% vs. 30% respectively; P  = 0.03.

SUMMARY

There have been an interest in developing and utilizing peptide-drug conjugates such as melflufen for treatment of patients with multiple myeloma, especially in the relapsed setting given historical results with alkylating agents, the use of which has been limited by dose-related toxicities in a disease that remains largely incurable. Single agent melflufen initially showed promising results especially in specific subgroups of heavily pretreated patients before the decision to suspend all clinical trials evaluating this agent after results from the OCEAN phase 3 trial. Subsequent reported analyses especially for melflufen-based combinations appear promising and suggest a potential use of peptide-drug conjugates provided optimal patient selection, as well as identification of the best companion agent.

Historical Perspective of High-Dose Therapy Followed by Autologous Stem Cell Transplantation in Multiple Myeloma

BACKGROUND

High-dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) has become part of standard of care (SOC) in newly diagnosed multiple myeloma. In this review, we provide a historical perspective on ASCT since its introduction in the 1990s.

SUMMARY

Overall survival (OS) benefit for HDT followed by ASCT was demonstrated in studies comparing HDT with ASCT to standard-dose therapy (SDT) before the era of novel agents. Conditioning is done with melphalan 200 mg/m2. Lower doses (MEL140, MEL150) for older patients with comorbidities are safe and have comparable results. The addition of busulfan to melphalan improves progression-free survival (PFS) but not OS. HDT with ASCT after induction with novel agents prolongs PFS but not OS compared to SDT alone. The benefit is more evident in patients with high-risk cytogenetics. Mobilization can be achieved with granulocyte colony-stimulating factor alone, but is improved with the addition of chemotherapy. Plerixafor reduces mobilization failure and enables sufficient stem cell collection after induction with novel agents. ASCT is safe with a low rate of mortality (1%), and selected patients can be managed as outpatients.

KEY MESSAGES

HDT followed by ASCT remains part of SOC due to its PFS benefit and relatively low toxicity.

Optimizing high dose melphalan

Melphalan, has been a major component of myeloma therapy since the 1950s. In the context of hematopoietic cell transplantation (HCT), high dose melphalan (HDM) is the most common conditioning regimen used due to its potent anti-myeloma effects and manageable toxicities. Common toxicities associated with HDM include myelosuppression, gastrointestinal issues, and mucositis. Established approaches to reduce these toxicities encompass dose modification, nausea prophylaxis with 5HT3 receptor antagonists, cryotherapy, amifostine use, and growth factors. Optimization of melphalan exposure through personalized dosing and its combination with other agents like busulfan, or bendamustine show promise. Propylene glycol-free melphalan (Evomela) represents a novel formulation aiming to enhance drug stability and reduce adverse effects. This review explores strategies to enhance the efficacy and mitigate the toxicity of HDM in multiple myeloma. Future directions involve exploring these strategies in clinical trials to improve the safety and efficacy of HDM, thereby enhancing outcomes for multiple myeloma patients undergoing autologous HCT.

Revisiting the Role of Alkylating Agents in Multiple Myeloma: Up-to-Date Evidence and Future Perspectives

From the 1960s to the early 2000s, alkylating agents (e.g., melphalan, cyclophosphamide, and bendamustine) remained a key component of standard therapy for newly-diagnosed or relapsed/refractory multiple myeloma (MM). Later on, their associated toxicities (including second primary malignancies) and the unprecedented efficacy of novel therapies have led clinicians to increasingly consider alkylator-free approaches. Meanwhile, new alkylating agents (e.g., melflufen) and new applications of old alkylators (e.g., lymphodepletion before chimeric antigen receptor T-cell [CAR-T] therapy) have emerged in recent years. Given the expanding use of antigen-directed modalities (e.g., monoclonal antibodies, bispecific antibodies, and CAR-T therapy), this review explores the current and future role of alkylating agents in different treatment settings (e.g., induction, consolidation, stem cell mobilization, pre-transplant conditioning, salvage, bridging, and lymphodepleting chemotherapy) to ellucidate the role of alkylator-based regimens in modern-day MM management.

Melflufen for the treatment of multiple myeloma

INTRODUCTION

Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate that takes advantage of increased aminopeptidase activity inside tumor cells to rapidly release alkylating agents therein. Melflufen in combination with dexamethasone has been evaluated in multiple clinical trials in patients with relapsed/refractory multiple myeloma (MM).

AREAS COVERED

This profile covers the unique mechanism of action of melflufen, the preclinical results supporting its activity in cellular models of resistance to chemotherapy, its activity in animal models of MM, and the clinical pharmacokinetics of melflufen. Findings from clinical trials evaluating melflufen, including the pivotal phase II HORIZON study and the phase III OCEAN study, are discussed.

EXPERT OPINION

Although MM treatment has improved, patients with disease refractory to multiple standard-of-care drug classes face a dismal prognosis. Melflufen demonstrated efficacy and tolerability in select populations, with an initial approval in the United States in patients with ≥ four previous lines of therapy and triple-class-refractory MM. Results from the phase III OCEAN study - currently under discussion with regulatory agencies in the United States and Europe - are more complex and have been put into context herein. Lastly, melflufen provides a proof-of-concept for the utility of the peptide-drug conjugate platform in relapsed/refractory MM.

Tumor Reduction in Multiple Myeloma: New Concepts for New Therapeutics

The development of new resources for a more accurate diagnosis and response assessment in multiple myeloma has been a long process for decades, mainly since the middle of the 20th century. During this time, the succession of technical advances has run parallel to the better knowledge of disease biology and the availability of novel therapeutic strategies. The cornerstone of standardized criteria to uniformly evaluate the disease response in myeloma dates back to the 1990s when the key role of complete remission was established. Since then, different updates have been implemented according to available scientific evidences not always without certain controversies. The progressive improvements in survival results of myeloma patients and the growing quality of responses due to the novel therapies have led to the need of developing new tools for better monitoring of tumor burden. In this way, the concept of minimal residual disease and its key value based on the prognostic significance and the clinical relevance has been consolidated during the last years, overcoming the value of conventional response criteria or classical adverse prognosis markers. Nevertheless, its precise role in the clinical management of myeloma patients to detect early treatment failure and trigger early rescue strategies is still pending to be defined. In this review, we revisit the major milestones in the understanding of tumor reduction in multiple myeloma until the most recent imaging techniques or liquid biopsy approaches, including a critical view of conventional response criteria, whose backbone has remained unchanged during the last 20 years.

Full or intensity-reduced high-dose melphalan and single or double autologous stem cell transplant with or without bortezomib consolidation in patients with newly diagnosed multiple myeloma

OBJECTIVE

A post hoc subgroup analysis of two phase III trials (NCT00416273, NCT00416208) was carried out to investigate the influence of 100/140 and 200 mg/m² melphalan as well as single/double autologous stem cell transplantation (ASCT) on progression-free survival (PFS). Additionally, the effect of bortezomib consolidation on PFS was analyzed.

METHODS

Following induction therapy and high-dose melphalan with subsequent ASCT, patients with newly diagnosed multiple myeloma (NDMM) were randomized 1:1 to either four 35-day cycles of bortezomib consolidation (1.6 mg/m² IV on days 1, 8, 15, 22) or observation.

RESULTS

Of the 340 patients included in this analysis, 13.5% received 1 × MEL100/140, 22.9% 2 × MEL100/140, 31.2% 1 × MEL200, and 32.4% 2 × MEL200. With higher cumulative melphalan dose, PFS improved (P = .0085). PFS curves of patients treated with 2 × MEL100/140 and 1 × MEL200 were very similar. The superior dose effect of MEL200 over MEL100/140 was non-existent in the bortezomib consolidation arm but pronounced in the observation arm (P = .0015). Similarly, double ASCT was only beneficial in patients without bortezomib consolidation (P = .0569).

CONCLUSIONS

Full dose melphalan and double transplantation seem advantageous only as long as patients are not receiving bortezomib consolidation afterwards.

Gastrointestinal toxicity of high-dose melphalan in autologous hematopoietic stem cell transplantation: identification of risk factors and a benchmark for experimental therapies

Gastrointestinal side effects are the dose-limiting toxicity of high-dose melphalan (HDM) in autologous hematopoietic stem-cell transplantation, but there are limited contemporary data on the incidence and severity of gastrointestinal toxicity associated with this regimen. We retrospectively studied 100 consecutive patients who received HDM alone or in combination with other conditioning agents. Patients had a median age of 56 (range 20-73); underlying diseases were myeloma (42%), lymphoma (42%), or amyloidosis (16%) and melphalan dosages were 200 (40%), 140 (59%), or 100 mg/m2 (1%). Ninety-seven percent of patients experienced diarrhea with a range of 1-18 bowel movements per day, 88% developed nausea, and 60% experienced vomiting. Abdominal CT scans rarely altered patient management, but stool studies were useful in identifying a treatable infectious source. Grade ≥ 2 diarrhea was associated with longer duration of diarrhea, longer length of stay, worse hypoalbuminemia, higher use of antibiotics, abdominal imaging, electrolyte repletions, and anti-diarrheal agents. Risk factors for severe diarrhea were female sex, melphalan dose, age > 50, creatinine clearance < 60 ml/min, and having a plasma cell neoplasm as opposed to lymphoma. Female sex was also associated with more severe nausea and vomiting. In summary, diarrhea remains an important toxicity of HDM and novel therapies for chemotherapy-induced diarrhea for patients undergoing stem-cell transplantation are needed. Grade 2 or higher diarrhea is associated with significant clinical consequences and should be used as the primary endpoint in prospective clinical trials.

Role of Stem Cell Transplantation in Multiple Myeloma

Autologous stem cell transplantation (auto-SCT) has been the standard of care in eligible newly diagnosed multiple myeloma (MM) patients. Outcomes of patients with MM have improved significantly due to the advent of several novel drugs. Upfront use of these drugs in induction therapy has significantly increased the rate and depth of responses that have translated into longer remission and survival. This has now raised a debate regarding the role and relevance of auto-SCT in the management of myeloma. However, clinical trials have confirmed the utility of auto-SCT even in the era of novel drugs. Tandem auto-SCT followed by maintenance has shown a progression-free survival (PFS) benefit in high-risk MM, and hence can be considered in young and fit patients with high-risk disease. Auto-SCT has the advantages of resetting the bone marrow microenvironment, short-lived toxicity compared to the long-term physical and financial toxicities of continued chemotherapy in the absence of SCT, very low transplant-related mortality (TRM) in high volume centers, and providing longer disease-free survival when followed by maintenance therapy. Allogeneic SCT is one potentially curative option for MM, albeit with an increased risk of death due to high TRM. Strategies to modulate the graft-versus-host disease (GVHD) while maintaining or improving the graft-versus-myeloma (GVM) effect could place allogeneic SCT back in the treatment armamentarium of MM.

The changing role of high dose melphalan with stem cell rescue in the treatment of newly diagnosed multiple myeloma in the era of modern therapies-back to the future!

State of the art treatment for myeloma involves using 3-drug combinations incorporating immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs). Clinical trials for 4-drug combinations incorporating monoclonal antibodies added to IMiD and PI based backbones are underway. Recent retrospective analyses show that patients who attain MRD negativity have similar long term outcomes regardless of early or delayed high dose melphalan with autologous stem cell support (HDM-ASCT). Given HDM-ASCT toxicity, not "overtreating" would be beneficial. Short of data from future prospective clinical trials addressing the question of the role of HDM-ASCT in MRD negative patients, varying expert opinions inherently arise. In this paper, we present the historical context of HDM-ASCT and data supporting 3-drug combinations. We then propose that a viable option for patients who reach MRD negativity is to transition to maintenance therapy directly without early HDM-ASCT, and reserving stem cell harvest to cases where HDM-ASCT is a possibility at relapse.

Salvage therapy versus upfront autologous stem cell transplantation in multiple myeloma patients with progressive disease after first-line induction therapy

It is a matter of debate whether myeloma patients with progressive disease (PD) after induction should receive salvage therapy or proceed directly to autologous stem cell transplantation. We performed a retrospective analysis of 1599 patients treated between 1991 and 2016 at the University Hospital of Heidelberg and other centers. Deepening of response through salvage therapy did not lead to better progression-free or overall survival (PD versus salvage therapy patients: HR = 0.71, 95% CI [0.28, 1.80], p = 0.5 and HR = 0.77, 95% CI [0.30, 1.95], p = 0.6, respectively), neither in patients treated with novel agents (HR = 0.66, 95% CI [0.23, 1.85], p = 0.4 and HR = 0.76, 95% CI [0.27, 2.15], p = 0.6) nor older regimens (HR = 0.86, 95% CI [0.36, 2.07], p = 0.7 and HR = 0.8, 95% CI [0.34, 1.91], p = 0.6). Therefore, primary nonresponders might benefit from a direct transplant rather than salvage induction, although the analyzed salvage therapy cohort was small (n = 23) and cytogenetics was not included in the multivariable analysis.

Autologous Stem Cell Transplantation for Multiple Myeloma: Single Centre Experience from North India

Autologous stem cell transplantation (ASCT) is considered as standard of care in patients with multiple myeloma (MM) patients aged 65 years or younger. We analyzed data of 94 patients of plasma cell dyscrasias who underwent 95 autologous transplants at our institute from October 2003 to Aug 2016. Other than 76 patients of newly diagnosed multiple myeloma, we also transplanted two patients of POEMS syndrome, two patients of plasma cell leukemia, three patients of concurrent light chain deposition disease, three patients of multifocal plasmacytomas, and eight patients of isolated light chain myeloma. One patient underwent transplant twice. The median age of patients was 53 years (range 21-65). The average interval between diagnosis and transplant was 10.51 ± 5.42 months. The predominant stage in the study cohort was ISS-III. IgG kappa was the commonest subtype of plasma cell dyscrasia (27.9%) followed by IgG lambda (16.27%). Renal involvement was seen in 25% patients at the time of transplantation. Following chemotherapy, 42% patients were in CR, 39% in VGPR, 5% had PR and 14% had progressive disease at the time of transplantation. All patients were conditioned with melphalan (dose 120-200 mg/m²) except for one who received an additional bortezomib for his second transplant. The mean time to neutrophil and platelet engraftment was 11.09 ± 1.82 and 12.69 ± 4.55 days respectively. Mucositis was noted in all patients (grade 3 in 37.5% patients). The median PFS (biochemical) was 55.8% and PFS (clinical) was 76.7% at 6.5 years. Thirteen percent of the transplanted patients succumbed to their illness of which three patients died within 30 days of transplant. Median OS was 76.7% at 6.5 years. ASCT is a feasible option for MM in India and the results are comparable.

Autotransplant with and without induction chemotherapy in older multiple myeloma patients: long-term outcome of a randomized trial

Autologous transplantation is controversial for older patients with multiple myeloma. The role of age-adjusted high-dose melphalan and the impact of induction chemotherapy cycles is still unclear. A total of 434 patients aged 60-70 years were randomly assigned to 4 cycles of standard anthracycline-based induction chemotherapy or no induction. For all patients, double autologous transplantation after melphalan 140 mg/m² (MEL140) was planned. The primary end point was progression-free survival. Of 420 eligible patients, 85% received a first transplant and 69% completed double transplantation. Treatment duration was short with a median of 7.7 months with induction chemotherapy cycles and 4.6 months without induction. On an intention-to-treat basis, median progression-free survival with induction chemotherapy cycles (207 patients) was 21.4 months versus 20.0 months with no induction cycles (213 patients) (hazard ratio 1.04, 95% confidence interval 0.84-1.28; P=0.36). Per protocol, progression-free survival was 23.7 months versus 23.0 months (P=0.28). Patients aged 65 years or over (55%) did not have an inferior outcome. Patients with low-risk cytogenetics [absence of del17p13, t(4;14) and 1q21 gains] showed a favorable overall survival and included the patients with sustained first remission. MEL140 was associated with a low rate of severe mucositis (10%) and treatment-related deaths (1%). Based on hazard ratio, the short treatment arm consisting of mobilization chemotherapy and tandem MEL140 achieved 96% of the progression-free survival, demonstrating its value as an independent component of therapy in older patients with multiple myeloma who are considered fit for autologous transplantation. (clinicaltrials.gov identifier: 02288741).

High melphalan exposure is associated with improved overall survival in myeloma patients receiving high dose melphalan and autologous transplantation

AIM

High dose melphalan (HDM) and autologous stem cell transplantation (ASCT) retains a central role in the treatment of myeloma. The aim of this study was to determine whether HDM exposure (area under the concentration vs. time curve, AUC), is significantly associated with transplant outcomes.

METHODS

Melphalan concentrations were measured in six to 11 plasma samples collected after HDM (median 192 mg m(-) (2) ) to determine melphalan AUC for a total of 114 patients. Binary logistic regression was used to assess whether melphalan AUC was associated with severe (≥ grade 3) oral mucositis. Multivariate Cox regression was used to assess whether melphalan AUC was significantly associated with time to progression, progression-free survival and overall survival (OS).

RESULTS

Melphalan AUC ranged from 4.9 to 24.6 mg l(-1)  h, median 12.84 mg l(-1) h. Melphalan AUC above the median was a risk factor for severe mucositis (HR 1.21, 95% CI 1.06, 1.38, P = 0.004) but was also associated with significantly improved overall survival (OS) (HR 0.40, 95% CI 0.20, 0.81, P = 0.001), with an estimated median survival of 8.50 years vs. 5.38 years for high vs. low AUC groups. Multivariate analysis did not identify melphalan AUC as being significantly associated with time to progression or progression-free survival.

CONCLUSIONS

This large scale pharmacodynamic analysis of HDM demonstrates that high melphalan exposure is associated with improved survival, with an acceptable increase in transplant toxicity. These results suggest studies targeting a higher AUC are warranted in patients undergoing HDM and ASCT for myeloma.

Furan oxidation based cross-linking: a new approach for the study and targeting of nucleic acid and protein interactions

The coming of age story of furan oxidation cross-linking.

Aprepitant, Granisetron, and Dexamethasone for Prevention of Chemotherapy-Induced Nausea and Vomiting After High-Dose Melphalan in Autologous Transplantation for Multiple Myeloma: Results of a Randomized, Placebo-Controlled Phase III Trial

Purpose

The optimal regimen to prevent chemotherapy-induced nausea and vomiting (CINV) for patients undergoing high-dose chemotherapy and autologous stem-cell transplantation (ASCT) is unclear. To evaluate the effect of aprepitant in addition to a standard regimen, we conducted this randomized, placebo-controlled phase III trial.

Patients and Methods

Patients with multiple myeloma were randomly assigned at a one-to-one ratio to receive either aprepitant (125 mg orally on day 1 and 80 mg orally on days 2 to 4), granisetron (2 mg orally on days 1 to 4), and dexamethasone (4 mg orally on day 1 and 2 mg orally on days 2 to 3) or matching placebo, granisetron (2 mg orally on days 1 to 4), and dexamethasone (8 mg orally on day 1 and 4 mg orally on days 2 to 3). Melphalan 100 mg/m2 was administered intravenously on days 1 to 2. ASCT was performed on day 4. The primary end point (complete response) was defined as no emesis and no rescue therapy within 120 hours of melphalan administration. Quality of life was assessed by modified Functional Living Index–Emesis (FLIE) questionnaire on days −1 and 6.

Results

Overall, 362 patients were available for the efficacy analysis (181 in each treatment arm). Significantly more patients receiving aprepitant reached the primary end point (58% v 41%; odds ratio [OR], 1.92; 95% CI, 1.23 to 3.00; P = .0042). Absence of major nausea (94% v 88%; OR, 2.37; 95% CI, 1.09 to 5.15; P = .026) and emesis (78% v 65%; OR, 1.99; 95% CI, 1.25 to 3.18; P = .0036) within 120 hours was increased by aprepitant. Mean total FLIE score (± standard deviation) was 114 ± 18 for aprepitant and 106 ± 26 for placebo (P < .001).

Conclusion

The addition of aprepitant resulted in significantly less CINV and had a positive effect on quality of life.

Not too little, not too much-just right! (Better ways to give high dose melphalan)

Of the 13 286 autologous haematopoietic cell transplant procedures reported in the US in 2010-2012 for plasma cell disorders, 10 557 used single agent, high-dose melphalan. Despite 30 years of clinical and pharmacokinetic (PK) experience with high-dose melphalan, and its continuing central role as cytoreductive therapy for large numbers of patients with myeloma, the pharmacodynamics and pharmacogenomics of melphalan are still in their infancy. The addition of protectant agents such as amifostine and palifermin allows dose escalation to 280 mg/m(2), but at these doses it is cardiac, rather than gut, toxicity that is dose-limiting. Although combination with additional alkylating agents is feasible, the additional TRM may not be justified when so many post-consolidation therapies are available for myeloma patients. Current research should optimise the delivery of this single-agent chemotherapy. This includes the use of newer formulations and real-time PKs. These strategies may allow a safe and effective platform for adding synergistic novel therapies and provide a window of lymphodepletion for the addition of immunotherapies.

Changing treatment paradigms for patients with plasma cell myeloma: impact upon immune determinants of infection

Plasma cell myeloma (PCM) is increasing in prevalence in older age groups and infective complications are a leading cause of mortality. Patients with PCM are at increased risk of severe infections, having deficits in many arms of the immune system due to disease and treatment-related factors. Treatment of PCM has evolved over time with significant impacts on immune function resulting in changing rates and pattern of infection. Recently, there has been a paradigm shift in the treatment of PCM with the use of immunomodulatory drugs and proteasome inhibitors becoming the standard of care. These drugs have wide-ranging effects on the immune system but their impact on infection risk and aetiology remain unclear. The aims of this review are to discuss the impact of patient, disease and treatment factors on immune function over time for patients with PCM and to correlate immune deficits with the incidence and aetiology of infections seen clinically in these patients. Preventative measures and the need for clinically relevant tools to enable infective profiling of patients with PCM are discussed.

Stem cell transplantation for multiple myeloma: current and future status

Stem cell transplantation (SCT) has been used in the treatment of multiple myeloma (MM) for decades and has become a standard of care for newly diagnosed MM patients. However, several important questions remain regarding the optimal use of SCT, particularly in light of the many recent advances in the treatment of MM. Bortezomib-based therapy or, in some cases, lenalidomide-based therapy should be considered as an induction therapy in transplantation-eligible patients. Efforts to improve upon the efficacy and safety of standard transplantation regimens (that is, high-dose melphalan) are also underway. Most published studies on the use of tandem autologous SCT were conducted before the advent of novel agents, such as thalidomide, lenalidomide and bortezomib, making it difficult to establish the current role of tandem SCT. Allogeneic SCT continues to be evaluated in clinical trials, and may have an important role in the treatment of transplantation-eligible patients with suitable donors. Post-transplantation consolidation and maintenance therapy using novel agents should be considered to improve outcomes in patients who fail to achieve a complete response following SCT. Patients in remission should be advised that continued therapy has been shown to prolong remission, improve quality of life and extend survival. Additional data on the optimal approach to post-transplantation therapy are needed. New strategies in development aimed at improving patient selection, safety and efficacy of SCT are likely to improve future outcomes.

Update on the role of autologous hematopoietic stem cell transplantation in multiple myeloma

Autologous stem cell transplantation is considered the standard of care for multiple myeloma patients aged < 65 years with no relevant comorbidities. The addition of drugs acting both on bone marrow microenvironment and on neoplastic plasma cells has significantly increased the proportion of patients achieving a complete remission after induction therapy, and these results are mantained after high-dose melphalan, leading to a prolonged disease control. Studies are being carried out in order to evaluate whether short term consolidation or long-term maintenance therapy can result into disease eradication at the molecular level thus increasing also patients survival. The efficacy of these new drugs has raised the issue of deferring the transplant after achiving a second response upon relapse. Another controversial point is the optimal treatment strategy for high-risk patients, that do not benefit from autologous stem cell transplantation and for whom the efficacy of new drugs is still matter of debate.

Autologous stem cell transplantation for multiple myeloma: identification of prognostic factors

INTRODUCTION

The purpose of this study was to evaluate the effect of prognostic factors on the outcome of patients with MM after ASCT.

PATIENTS AND METHODS

We analyzed results of 170 consecutive patients (121 male and 49 female) of MM who underwent ASCT. Patients' median age was 52 years (range, 26-68 years). High dose melphalan (200 mg/m(2)) was used for conditioning. One hundred thirty-two patients (77.6%) had evidence of chemosensitive disease before transplant. Response was assessed using European Group for Blood and Bone Marrow Transplantation criteria.

RESULTS

Post ASCT 44.7% of patients achieved CR, 24.7% had very good partial response (VGPR), and 21.2% had partial response (PR). Presence of pretransplant chemosensitive disease (CR, VGPR, and PR) and transplant within 12 months of diagnosis for years before 2006 were associated with higher response rates on multivariate analysis. At a median follow-up of 84 months, median overall (OS) and event-free survival (EFS) is 85.5 and 41 months, respectively. Estimated OS and EFS at 60 months is 62 ± 0.04% and 41 ± 0.04%, respectively. Patients who responded to transplant (CR, VGPR, and PR) had a longer OS (P < .001) and EFS (P < .001). Additionally, patients who achieved CR post transplant had a longer OS (P < .001) and EFS (P < .001). Patients who received novel agents for induction pretransplant had a longer OS (P < .001) and EFS (P < .002).

CONCLUSION

Outcome after ASCT is better for myeloma patients with pretransplant chemosensitive disease and those who achieve CR after transplant.

Fifty years of melphalan use in hematopoietic stem cell transplantation

Melphalan remains the most widely used agent in preparative regimens for hematopoietic stem cell transplantation (SCT). From its initial discovery more than 50 years ago, it has been gradually incorporated in the conditioning regimens for both autologous and allogeneic transplantations because of its myeloablative properties and broad antitumor effects as a DNA alkylating agent. Melphalan remains the mainstay conditioning for multiple myeloma and lymphomas, and it has been used successfully in preparative regimens of a variety of other hematological and nonhematological malignancies. The addition of newer agents to conditioning, such as bortezomib or lenalidomide for myeloma or clofarabine for myeloid malignancies, may improve antitumor effects for transplantation, whereas melphalan in combination with alemtuzumab may represent a backbone for future cellular therapy because of reliable engraftment and low toxicity profile. This review summarizes the development and the current use of this remarkable drug in hematopoietic SCT.

Phase I trial of bortezomib during maintenance phase after high dose melphalan and autologous stem cell transplantation in patients with multiple myeloma

We enrolled 15 patients in this phase I dose de-escalation trial. Twelve patients are evaluable. The primary objective was to determine the safest and best tolerated maintenance dosing (MD) of bortezomib (B). The secondary endpoints were to evaluate complete response (CR), overall response (OR) and response duration. All patients receiving autologous stem cell transplant (ASCT) were eligible and registered between D+30 to D+120 after ASCT. A maximum number of 8 cycles of B was planned. Two evaluable patients in level (L) 1 received therapeutic dose of B 1.3 mg/m(2) intravenously on days (D) 1, 4, 8, and 11 in a 21 day cycle. Both these patients experienced dose limiting toxicities (DLTs). Four evaluable patients were then enrolled in dose L2 utilizing B 1.3 mg/m(2) on D 1, 4, 8, and 11 in a 28 day cycle. Two patients in L2 developed DLTs. Six evaluable patients were thereafter enrolled in L3 utilizing B 1 mg/m(2) on D 1, 8, and 15 in a 28 day cycle. Median 8 cycles of B were administered (2-8). No DLTs were observed in L3. The median duration of follow up for the entire cohort is 33 months (12-62). The median duration of response in L3 is 29.1 months (12-33). We conclude that B 1 mg/m(2) administered intravenously and may be subcutaneously on D 1, 8, and 15 in a 28 day cycle is the best tolerated MD and can be safely given beginning around D+100 post-ASCT.

Current trends in autologous stem-cell transplantation for myeloma in the era of novel therapies

Since the mid 1990s, high-dose therapy followed by autologous stem-cell transplantation (ASCT) has been considered the standard of care for frontline therapy in younger patients with multiple myeloma (MM). During the past 10 years, thalidomide, bortezomib, and lenalidomide have been widely incorporated to the therapeutic armamentarium for the treatment of this disease. These agents show promise for improving the rate of complete remission both before and after ASCT without increasing toxicity. However, it is not clear whether such therapies are superior if they are used as an alternative to transplantation or whether they may reduce the need for and use of transplantation in patients in whom treatment is indicated. Therefore, the role of ASCT itself is a matter of debate: Should it be used upfront or as salvage treatment at the time of progression in patients initially treated with novel agents? This review presents current trends in ASCT for MM in the era of novel therapies.

Stem cell transplantation for multiple myeloma: current and future status

High-dose melphalan with autologous stem cell support has been an integral part of myeloma therapy for more than 25 years, either as salvage therapy or as consolidation of an initial remission. Although multiple phase 3 trials have demonstrated that this therapy results in higher response rates and longer remission times than conventional chemotherapy, the use of thalidomide, lenalidomide, and bortezomib as induction therapy has limited the clinical relevance of these trials. Moreover, ongoing trials have shown that initial induction therapy may affect transplantation outcome, and that long-term disease control can be achieved in a substantial number of patients with a variety of posttransplantation maintenance therapies. This article summarizes the results of ongoing and recently published clinical trials and describes how they have affected current transplantation recommendations.

Busulfan 12 mg/kg plus melphalan 140 mg/m2 versus melphalan 200 mg/m2 as conditioning regimens for autologous transplantation in newly diagnosed multiple myeloma patients included in the PETHEMA/GEM2000 study

BACKGROUND

The aim of this study was to compare the long-term safety and efficacy of oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) and melphalan 200 mg/m(2) as conditioning regimens for autologous stem cell transplantation in newly diagnosed patients with multiple myeloma in the GEM2000 study.

DESIGN AND METHODS

The first 225 patients received oral busulfan 12 mg/kg plus melphalan 140 mg/m(2); because of a high frequency of veno-occlusive disease, the protocol was amended and a further 542 patients received melphalan 200 mg/m(2).

RESULTS

Engraftment and hospitalization times were similar in both groups. Oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) resulted in higher transplant-related mortality (8.4% versus 3.5%; P=0.002) due to the increased frequency of veno-occlusive disease in this group. Response rates were similar in both arms. With respective median follow-ups of 72 and 47 months, the median progression-free survival was significantly longer with busulfan plus melphalan (41 versus 31 months; P=0.009), although survival was similar to that in the melphalan 200 mg/m(2) group. However, access to novel agents as salvage therapy after relapse/progression was significantly lower for patients receiving busulfan plus melphalan (43%) than for those receiving melphalan 200 mg/m(2) (58%; P=0.01).

CONCLUSIONS

Conditioning with oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) was associated with longer progression-free survival but equivalent survival to that achieved with melphalan 200 mg/m(2) but this should be counterbalanced against the higher frequency of veno-occlusive disease-related deaths. This latter fact together with the limited access to novel salvage therapies in patients conditioned with oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) may explain the absence of a survival difference. Oral busulfan was used in the present study; use of the intravenous formulation may reduce toxicity and result in greater efficacy, and warrants further investigation in myeloma patients. (Clinicaltrials.gov identifier: NCT00560053).

The evolution and impact of therapy in multiple myeloma

Multiple myeloma is a clonal B-cell malignancy characterized by aberrant expression of plasma cells within the bone marrow, and is associated with the well known clinical manifestations anemia, bone disease, renal dysfunction, hypercalcemia, and recurrent infections. For many years, melphalan and prednisone represented the standard of care in multiple myeloma therapy, with stem cell transplantation reserved for selected patients. Treatment of the disease has evolved rapidly over the past decade, however, with the development and utilization of thalidomide, lenalidomide, and bortezomib. As a result of these developments, clinical outcomes have improved significantly. This review highlights important historic landmarks as well as more recent events that have played an important role in the evolution of myeloma therapy.

Melphalan/prednisone versus drug combinations for plasma cell myeloma

Reports of 13 prospective, randomized clinical trials comparing standard treatment with melphalan and prednisone (MP) versus various drug combinations in the treatment of myeloma patients are presented. These studies reveal that patients with Durie-Salmon Stage III disease respond significantly more frequently to MP and drug combinations than those with Stage I and II. Drug combinations may be more effective in inducing objective responses. The response rates were significantly better for the drug combinations in 3 of the 13 comparisons. There was little evidence that either form of treatment was superior in prolonging survival, for in one study the patients treated with a drug combination lived significantly longer than those treated with MP, while in another the reverse was true, and there was no difference in the survival of the two groups in the remaining 11 studies. In the Vth MRC myelomatosis trial, patients treated with a combination of adriamycin, carmustine, cyclophosphamide and melphalan are living significantly longer than those treated with melphalan alone, and this survival advantage persists after correction for the most important prognostic factor, beta 2 microglobulin. Attempts to increase the intensity of treatment by using syngeneic, allogeneic or autologous marrow transplantation to rescue patients following otherwise lethal chemoradiotherapeutic treatments, have not yet demonstrated conclusively that the myeloma clone can be eliminated by this form of treatment.

High-dose chemotherapy and autologous bone marrow transplantation for myeloma

In three studies we have attempted to increase the complete remission rate in a series of patients with multiple myeloma under the age of 69. A CR rate of 27% was seen in 63 patients treated with intravenous high-dose melphalan 140 m/m2 with or without the addition of high-dose methyl prednisolone 1 g/m2 for 5 days (in 22 patients). In a third study a CR rate of 50% was seen in 50 patients treated in a programme in which vincristine, adriamycin and methyl prednisolone was first given and patients then received high-dose melphalan 140-200 mg/m2 with an autologous bone marrow transplant where possible. Median remission duration in the first two studies was 19 months with a median survival of 5 years. A definition of complete remission in myeloma is proposed.

Maintenance treatment of multiple myeloma

In multiple myeloma (MM), low-cost maintenance treatment has some attractions, since maintenance of a small tumor is usually compatible with a fairly healthy state. However, the great majority of the studies of maintenance treatment have failed to show any clinical benefit. Based on simple theoretical consideration, it is shown that in MM response duration and survival are affected primarily by the residual tumor mass after primary treatment, and by the kinetics of the tumor. Continuation of maintenance treatment is likely to have a moderate effect. The main cause of that is identified in the presence or in the development of a substantial proportion of drug-resistant cells. Preliminary data suggest that only alpha-interferon can be useful for maintenance, and that it can act by slowing down the kinetics of the tumor.

Chemotherapy for resistant and relapsing multiple myeloma

This report summarizes a broad experience in the treatment of patients with multiple myeloma resistant to standard chemotherapy. The VAD regimen has induced remissions in about 50% of relapsing patients but in only about 25% of previously unresponsive patients. In patients resistant to VAD, high-dose therapies with intravenous melphalan, a CBV combination (cyclophosphamide-BCNU-VP-16) or an EDAP regimen (VP-16 -platinum) produced responses in about 40% of patients. However, these treatments usually required autologous bone marrow or blood stem cell support and the median duration of control was only 6 months. With an even more intensive program using high-dose melphalan and total body irradiation supported by autologous bone marrow, all patients who survived the early treatment period responded for a median duration of about 1 year. Results indicated a dose-response effect of chemoradiotherapy on VAD-resistant myeloma with the potential that such intensive regimens will prolong disease-free survival time.

Multiple myeloma

Multiple myeloma is a clonal plasma cell malignancy that accounts for slightly more than 10% of all hematologic cancers. In this paper, we present a historically focused review of the disease, from the description of the first case in 1844 to the present. The evolution of drug therapy and stem-cell transplantation for the treatment of myeloma, as well as the development of new agents, is discussed. We also provide an update on current concepts of diagnosis and therapy, with an emphasis on how treatments have emerged from a historical perspective after certain important discoveries and the results of experimental studies.

Future challenges

Treatment for patients with myeloma has changed unrecognisably over the last two decades and now includes a sequence of treatments including chemotherapy, biological targeted therapy with or without consideration for high-dose therapy (autologous and allogeneic stem cell transplantation for younger and fit patients). As patients can now expect a doubling of median survival and a 20-30% chance of surviving longer than 10 years, the focus of treatment is shifting to long-term quality of life. This article focuses on future challenges facing clinicians treating myeloma and how best we may optimize our resources.

The evolving background for high-dose treatment for myeloma

In the constantly evolving field of myeloma, this special issue is slanted towards how the newer targeted treatments fit in with various transplantation strategies. High-dose treatment for myeloma with autologous stem cell transplantation started 25 years ago, with the consequence of producing complete remissions and a doubling of survival. Since then, its role has been refined and it has been accepted as standard treatment. The current challenge is to optimize its use into a background of the development, availability and regulatory approval of newer targeted therapies such as Thalidomide, Revlimid (Lenalidomide) and Velcade (Bortezomib). This special issue addresses these problems, and gives particular emphasis on the attainment of very long-term survival, with normal quality of life for patients with myeloma who do not necessarily need to be cured of their molecular disease, that is, they are 'operationally cured.' It is hoped that the reader will find the information in this issue useful in the day-to-day management of patients and we hope that this will also inspire new research directions designed to improve the outcome of patients with myeloma.

Growth factor-assisted chemotherapy--the Manchester experience

Stimulation of red cell production by erythropoietin and of granulocyte production by granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage-CSF (GM-CSF) has been demonstrated in several clinical studies. The first study to show that a human CSF could be used to shorten the period of neutropenia and reduce the risk of serious infection following intensive combination chemotherapy was carried out in Manchester using G-CSF. The period of neutropenia was significantly shortenened (by a median of 80%) and the neutrophil count levels were restored and above normal by 14 days after chemotherapy. In view of these results a further study was undertaken to examine the possibility of using intensive two weekly chemotherapy under cover of G-CSF. Treatment with Doxorubicin at doses of 75, 100, 125 and 150 mg/m2 was followed by infusion of G-CSF for 11 days. The neutrophil counts returned to normal within 12-14 days, allowing the delivery of up to three cycles of high dose chemotherapy at 14 day intervals. These studies demonstrated that intensive chemotherapy with dose-limiting myelodepression can be given with increased frequency under cover of G-CSF. Our studies using GM-CSF have also shown that administration by continuous i.v. infusion can reduce the period of life-threatening neutropenia following high dose Melphalan (120 mg/m2) without resort to autologous bone marrow transplantation (ABMT). In this study the period of granulocytopenia following Melphalan (less than 500 g x 10(9)/m2) was less than 15 days. This compares favourably with other series using high dose Melphalan followed by ABMT without CSF, where the duration of severe neutropenia was prolonged beyond three weeks. Although it appears that G-CSF and GM-CSF should be given either by continuous i.v. infusion or s.c. injection at doses between 3-10 micrograms/kg/day to obtain maximum biological effect, a great deal more work is required to determine optimum schedules and investigate the possibility of using more than one bioregulator.

Melphalan: old and new uses of a still master drug for multiple myeloma

The treatment of multiple myeloma has seen significant changes from the initial use of melphalan to the introduction of stem cell transplantation and, most recently, to the era of novel targeted agents. Melphalan still remains as a reference drug for combination regimens, including emerging newer therapeutic options, either used at a standard dose for initial or salvage treatments in patients who are not eligible for more intensive therapies, or in conjunction with new molecules within high-dose chemotherapy programs. In this review, the authors analyze old and novel regimens, including melphalan for the treatment of newly diagnosed or relapsed/resistant patients with multiple myeloma in the clinical settings of standard chemotherapy, as well as autologous or allogeneic stem cell transplantation.

Marked Recovery of Severe Renal Lesions in POEMS Syndrome With High-Dose Melphalan Therapy Supported by Autologous Blood Stem Cell Transplantation

POEMS syndrome is a rare plasma cell disorder, characterized by polyneuropathy, organomegaly, endocrinopathy, serum monoclonal protein, and skin lesions. Although not included in the acronym, renal lesions also are characteristic of this disease and sometimes require dialysis therapy. We treated a 61-year-old woman with POEMS syndrome with high-dose melphalan therapy (HDT) supported by autologous blood stem cell transplantation (SCT), and clinical remission was achieved. A repeated renal biopsy showed the striking effectiveness of this therapy on renal lesions. Pathological features of the renal lesions, such as membranoproliferative glomerulonephritis-like lesions, microangiopathic glomerulopathy, and mesangiolytic lesions with microcapillaries, almost completely disappeared. This treatment also markedly decreased serum levels of vascular endothelial growth factor (VEGF). These findings indicate that HDT with SCT is effective, even on renal lesions in patients with POEMS syndrome, and suggest that high serum VEGF concentrations are associated closely with the development of renal lesions in patients with this type of plasma cell disorder.

Stem-cell transplantation in multiple myeloma

In patient with newly diagnosed multiple myeloma (MM), randomized studies have shown that autologous stem-cell transplantation (ASCT) is superior to conventional chemotherapy, and ASCT is now standard care, at least for younger patients. The best conditioning regimen is melphalan 200 mg/m2, and the best stem-cell source is unselected peripheral progenitor cells. Recent results of the IFM94 trial show that double ASCT is superior to single ASCT, at least in patients who do not achieve a 90% response after one transplant. By combining biologic markers (beta2-microglobulin, albumin) and genetic markers (hypodiploidy, chromosome 13 deletion) it is possible to accurately predict prognosis after ASCT. The results of allogeneic SCT remain disappointing due to a high transplant mortality. Strategies combining ASCT and reduced-intensity allogeneic SCT are currently being studied.