Lenalidomide and Vorinostat Maintenance after Autologous Transplantation in Multiple Myeloma: Long- Term Follow-Up

Decoding DNA methylation in epigenetics of multiple myeloma

Dysregulation of DNA methylation in B cells has been observed during their neoplastic transformation and therefore closely associated with various B-cell malignancies including multiple myeloma (MM), a malignancy of terminally differentiated plasma cells. Emerging evidence has unveiled pronounced alterations in DNA methylation in MM, including both global and gene-specific changes that can affect genome stability and gene transcription. Moreover, dysregulated expression of DNA methylation-modifying enzymes has been related with myelomagenesis, disease progression, and poor prognosis. However, the functional roles of the epigenetic abnormalities involving DNA methylation in MM remain elusive. In this article, we review current understanding of the alterations in DNA methylome and DNA methylation modifiers in MM, particularly focusing on DNA methyltransferases (DNMTs) and tet methylcytosine dioxygenases (TETs). We also discuss how these DNA methylation modifiers may be regulated and function in MM cells, therefore providing a rationale for developing novel epigenetic therapies targeting DNA methylation in MM.

Future Directions in Maintenance Therapy in Multiple Myeloma

Autologous stem cell transplantation (ASCT) has been a backbone of therapy for newly diagnosed patients with multiple myeloma eligible for high-dose therapy for decades. Survival outcomes have continued to improve over time, in part because of the incorporation of highly effective induction regimens prior to ASCT as well as post-ASCT maintenance therapy. Randomized phase III clinical trials have helped establish lenalidomide maintenance as a standard of care. However, as nearly all patients will eventually experience disease relapse, there continues to be significant interest in developing novel maintenance strategies to improve upon lenalidomide maintenance. In this review, we summarize the available evidence for the use of immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies as post-ASCT maintenance therapies as well as discuss future directions and unanswered questions in the field.

Advances in maintenance strategy in newly diagnosed multiple myeloma patients eligible for autologous transplantation

INTRODUCTION

Multiple myeloma (MM) lacks curative therapy. Therefore, researchers continue to conduct studies in an effort to improve progression-free survival (PFS) and overall survival (OS). Maintenance therapy (MT) after autologous stem cell transplant (ASCT) was extensively studied in the last decade and now considered a standard approach.

AREAS COVERED

This review evaluated the evidence and updates on various maintenance agents in newly diagnosed multiple myeloma (NDMM) after ASCT. Articles were searched on PubMed and Embase that were published in last 10 years. Both clinical trials and observational studies were evaluated.

EXPERT OPINION

Maintenance strategy after ASCT has consistent PFS benefit but lacks conclusive OS improvement. Lenalidomide is superior to thalidomide given reduced neurotoxicity. OS advantage is controversial for both due to inconsistent evidence. Lenalidomide may confer a PFS advantage even at lower doses due to toxicity with higher doses. Bortezomib-based maintenance has some evidence for OS benefit in high-risk MM (HRMM) and renal dysfunction. Ixazomib has preliminary promising results. Two or three drug combinations for MT are potentially safe and more effective, particularly in HRMM although data on this subject is still evolving. Efficacy of various MT regimens in terms of minimal residual disease status needs to be further investigated.