Proteomics-inspired precision medicine for treating and understanding multiple myeloma

Introduction

Remarkable progress in molecular characterization methods has led to significant improvements in how we manage multiple myeloma (MM). The introduction of novel therapies has led to significant improvements in overall survival over the past 10 years. However, MM remains incurable and treatment choice is largely based on outdated risk-adaptive strategies that do not factor in improved treatment outcomes in the context of modern therapies.

Areas covered

This review discusses current risk-adaptive strategies in MM and the clinical application of proteomics in the monitoring of treatment response, disease progression, and minimal residual disease (MRD). We also discuss promising biomarkers of disease progression, treatment response, and chemoresistance. Finally, we will discuss an immunomics-based approach to monoclonal antibody (mAb), vaccine, and CAR-T cell development.

Expert opinion

It is an exciting era in oncology with basic scientific knowledge translating in novel therapeutic approaches to improve patient outcomes. With the advent of effective immunotherapies and targeted therapies, it has become crucial to identify biomarkers to aid in the stratification of patients based on anticipated sensitivity to chemotherapy. As a paradigm of diseases highly dependent on protein homeostasis, multiple myeloma provides the perfect opportunity to investigate the use of proteomics to aid in precision medicine.

Efficacy of venetoclax as targeted therapy for relapsed/refractory t(11;14) multiple myeloma

Venetoclax is a selective, orally bioavailable BCL-2 inhibitor that induces cell death in multiple myeloma (MM) cells, particularly in those harboring t(11;14), which express high levels of BCL-2 relative to BCL-X_L and MCL-1. In this phase 1 study, patients with relapsed/refractory MM received venetoclax monotherapy. After a 2-week lead-in with weekly dose escalation, daily venetoclax was given at 300, 600, 900, or 1200 mg in dose-escalation cohorts and 1200 mg in the safety expansion. Dexamethasone could be added on progression during treatment. Sixty-six patients were enrolled (30, dose-escalation cohorts; 36, safety expansion). Patients received a median of 5 prior therapies (range, 1-15); 61% were bortezomib and lenalidomide double refractory, and 46% had t(11;14). Venetoclax was generally well tolerated. Most common adverse events included mild gastrointestinal symptoms (nausea [47%], diarrhea [36%], vomiting [21%]). Cytopenias were the most common grade 3/4 events, with thrombocytopenia (32%), neutropenia (27%), anemia (23%), and leukopenia (23%) reported. The overall response rate (ORR) was 21% (14/66), and 15% achieved very good partial response or better (≥VGPR). Most responses (12/14 [86%]) were reported in patients with t(11;14). In this group, ORR was 40%, with 27% of patients achieving ≥VGPR. Biomarker analysis confirmed that response to venetoclax correlated with higher BCL2:BCL2L1 and BCL2:MCL1 mRNA expression ratios. Venetoclax monotherapy at a daily dose up to 1200 mg has an acceptable safety profile and evidence of single-agent antimyeloma activity in patients with relapsed/refractory MM, predominantly in patients with t(11;14) abnormality and those with a favorable BCL2 family profile. Registered at www.clinicaltrials.gov: #NCT01794520.

Optimizing current and emerging therapies in multiple myeloma: a guide for the hematologist

Multiple myeloma (MM) is the second most common hematologic malignancy. The diagnosis of MM requires ⩾10% clonal plasma cells in the bone marrow or biopsy-proven plasmacytoma, plus evidence of end-organ damage (hypercalcemia, renal failure, anemia, and lytic bone lesions). The definition of MM has recently been expanded to include a ⩾60% clonal plasma cell burden in the bone marrow, serum involved/uninvolved light chain ratio of ⩾100, or more than one focal lesion on magnetic resonance imaging ⩾5 mm in the absence of end-organ damage. MM is an incurable malignancy previously associated with poor survival rates. However, over the past two decades, the introduction of novel treatment options has resulted in a dramatic improvement in response rates and overall survival (OS). The combination of a proteasome inhibitor and an immunomodulator (IMiD) is the preferred induction treatment for newly diagnosed transplant-eligible MM patients. After induction, high-dose therapy with autologous stem cell transplant (ASCT) is still the standard of care for these patients. In patients who are transplant ineligible, dose adjusted IMiDs or proteasome inhibitor-based combinations are the preferred treatment option. With the recent approval of novel drugs like carfilzomib, ixazomib, pomalidomide, panobinostat, and monoclonal antibodies (elotuzumab and daratumumab), as well as improved understanding of risk stratification, management of comorbidities and treatment side effects, clinicians can optimize anti-MM therapy, particularly in relapse/refractory MM patients. In this review, we outline the current therapeutic approach to the management of MM.