Old and new generation immunomodulatory drugs in multiple myeloma

INTRODUCTION

Over the last two decades, the outcomes of patients with multiple myeloma (MM), a malignant plasma cells dyscrasia, have dramatically improved. The development and the introduction of the immunomodulatory drugs (IMiDs) which include thalidomide, lenalidomide, and pomalidomide, have contributed significantly to these improvements.

EVIDENCE ACQUISITION

The IMiDs have been shown a multitude of mechanisms of action, including antiangiogenic, cytotoxic and immunomodulatory. The more recent discoveries that the IMiDs bind to cereblon and thus regulate the ubiquitination of key transcription factors including IKZF1 and IKZF3, have provided new insight about their activities.

EVIDENCE SYNTHESIS

The IMIDs are widely used in the treatment of the different setting of MM patients and particularly lenalidomide represents the backbone in the therapy of newly diagnosed transplant eligible and transplant ineligible patients, in the maintenance setting post-transplant and in the relapsed/refractory setting, while pomalidomide is currently utilized in the relapsed/refractory setting.

CONCLUSIONS

Here the mechanisms of action, the clinical efficacy and the management of side effects are reviewed as well as the new classes of cereblon E3 ligase modulator (CELMoD) and their promising clinical data are described.

Should Overall Survival Remain an Endpoint for Multiple Myeloma Trials?

PURPOSE OF REVIEW

While the traditional gold standard for demonstrating clinical benefit of a therapy has been to show prolongation of overall survival (OS), there are multiple factors which can hinder the use of OS as a primary endpoint in randomized clinical trials (RCTs). Here, we analyze recent myeloma RCTs and evaluate the issues relevant to current and future myeloma RCT design.

RECENT FINDINGS

A review of recent phase III RCTs that led to approval of new agents/combinations reveals that none were designed with OS as the primary endpoint, but instead utilized time to progression (TTP) or progression-free survival (PFS). These studies illuminate the inherent difficulties of designing trials with the primary endpoint of OS/PFS in a disease characterized by increasingly prolonged survival times, availability of effective salvage therapies, and competing events such as co-morbid conditions. Alternative primary endpoints other than OS or PFS need to be developed for future myeloma RCTs. Validated surrogate endpoints with novel clinical trial designs will help improve the feasibility of conducting comparative clinical trials in a timely manner.

Treatment of relapsed multiple myeloma: Evidence-based recommendations

The practice of choosing the next best therapy for patients with relapsed and/or refractory multiple myeloma (RRMM) is becoming increasingly complex. There is no clear consensus regarding the best treatment sequence for RRMM. With the approval of novel proteasome inhibitors (ixazomib and carfilzomib), immunomodulatory agents (pomalidomide), monoclonal antibodies (daratumumab and elotuzumab), and other targeted therapies, multiple combination regimens utilizing these agents are being studied with the goal of enhancing disease control, prolonging progression-free survival, and improving overall survival. We, herein, describe a review of FDA-approved regimens for RRMM patients and offer a paradigm in selecting subsequent treatment regimens, focusing on patient specific morbidity, treatment toxicity, and disease-specific characteristics.

Relapsed refractory multiple myeloma: a comprehensive overview

Most patients with relapsed/refractory multiple myeloma (RRMM) have been treated with drug combinations including a proteasome inhibitor (PI) and/or an immunomodulatory drug (IMiD). The goal of therapy for such patients is therefore to achieve disease control with acceptable toxicity and patient-defined decent quality of life. Physicians face a difficult task not only deciding who to treat, but also when to treat and how to treat, utilizing knowledge of previously administered therapies, patient comorbidities, potential adverse events, and patient wishes to make such a critical decision. New drugs and combination regimens are continuously underway thus broadening the options for therapy and giving way to a more individualized approach for patients with RRMM. The integration of novel agents into the treatment paradigm has shifted the perception of multiple myeloma (MM) from an incurable, fatal disease to a manageable, chronic one. This comprehensive review addresses the results and challenges posed by many of the newer agents for the treatment of RRMM. It attempts to propose a universal strategy for optimal therapy decision-making thus answering three simple fundamental questions-when to treat, how to treat, and how long to treat for.

The first-in-human study of the pan-PIM kinase inhibitor PIM447 in patients with relapsed and/or refractory multiple myeloma

PIM447, a novel pan-PIM inhibitor, has shown preclinical activity in multiple myeloma (MM). In the multicenter, open-label, first-in-human study, patients with relapsed and/or refractory MM were enrolled to determine the maximum-tolerated dose (MTD) or recommended dose (RD), safety, pharmacokinetics, and preliminary anti-myeloma activity of PIM447. PIM447 was administered in escalating oral doses of 70-700 mg once daily (q.d.) for 28-day continuous cycles. Seventy-nine patients with a median of four prior therapies were enrolled. Seventy-seven patients (97.5%) had an adverse event (AE) suspected as treatment related, with treatment-related grade 3/4 AEs being mostly hematologic. Eleven dose-limiting toxicities occurred, and an MTD of 500 mg q.d. and an RD of 300 mg q.d. were established. The main reason for discontinuation was disease progression in 54 patients (68.4%). In the entire study population, a disease control rate of 72.2%, a clinical benefit rate of 25.3%, and an overall response rate of 8.9% were observed per modified International Myeloma Working Group criteria. Median progression-free survival at the RD was 10.9 months. PIM447 was well tolerated and demonstrated single-agent antitumor activity in relapsed/refractory MM patients, providing proof of principle for Pim (Proviral Insertions of Moloney Murine leukemia virus) kinase inhibition as a novel therapeutic approach in MM.

Treatment of patients with multiple myeloma progressing on frontline-therapy with lenalidomide

Over the last years, there has been great progress in the treatment of multiple myeloma with many new agents and combinations having been approved and being now routinely incorporated into treatment strategies. As a result, patients are experiencing benefits in terms of survival and better tolerance. However, the multitude of treatment options also presents a challenge to select the best options tailored to the specific patient situation. Lenalidomide is increasingly being used as part of frontline therapy in newly diagnosed multiple myeloma. This agent is typically administered until disease progression. It is currently unclear, how to best manage patients, who relapse while receiving lenalidomide as part of their frontline treatment. We conducted a review to summarize the available evidence in this setting. Our summary shows that there are very few data from current trials testing new combinations based on carfilzomib, pomalidomide, or daratumumab that address this specific patient population. Our review is aimed to summarize the available evidence to assist treatment decision making and to raise awareness of this lack of data to encourage further analyses and the incorporation of sequencing questions in future trial designs.

New Drugs in Multiple Myeloma

Multiple myeloma is diagnosed in over 100,000 patients each year worldwide, has an increasing incidence and prevalence in many regions, and follows a relapsing course, making it a significant and growing healthcare challenge. Recent basic, translational, and clinical studies have expanded our therapeutic armamentarium, which now consists of alkylating agents, corticosteroids, deacetylase inhibitors, immunomodulatory agents, monoclonal antibodies, and proteasome inhibitors. New drugs in these categories, and additional agents, including both small and large molecules, as well as cellular therapies, are under development that promise to further expand our capabilities and bring us closer to the cure of this plasma cell dyscrasia.

Triplet therapies - the new standard of care for multiple myeloma: how to manage common toxicities

Introduction: Multiple three drug combination regimens have been approved for the treatment of multiple myeloma in the last few years. Triplets have become the new standard of care for transplant eligible and ineligible patients with newly diagnosed as well as relapsed multiple myeloma. Novel agents have a unique profile of side effects. The management of toxicities is important to maintain quality of life and maximize treatment duration and benefit. Areas covered: This article reviews efficacy data, incidence of key adverse events and provide recommendations and expert opinion regarding how to manage common toxicities in triplet therapies. Relevant publications and abstracts were searched in PubMed, ASH, ASCO and EHA meetings. Guidelines from IMWG, NCCN, ESMO and ASCO, published trial protocols and prescribing information were used to formulate recommendations for the management of toxicities. Expert commentary: Side effects are a critical factor guiding the selection of optimal chemotherapy regimens for multiple myeloma. The majority of toxicities encountered with triplet therapies are reversible and can be readily managed with supportive care and dose modifications.

Approach to the treatment of the older, unfit patient with myeloma from diagnosis to relapse: perspectives of a US hematologist and a geriatric hematologist

Mrs. A. is a 73-year-old woman who has developed increasing fatigue and lower back pain over the past year. The pain limits her exercise tolerance such that she can now walk only 1 block. She is a retired schoolteacher who does volunteer efforts in her community but has limited her activities due to fatigue. Karnofsky performance status is 70%. She has a history of chronic hypertension treated with a diuretic, adult-onset diabetes mellitus treated with metformin, and hypothyroidism treated with levothyroxine. Initial evaluation reveals anemia, renal dysfunction, an elevated total protein, and an L2 compression fracture on lumbosacral radiographs. Results of initial and subsequent evaluation are shown below, and she is referred to a hematologist for further evaluation, which revealed the following: calcium 9.0 mg/dL, creatinine 3.2 mg/dL with estimated creatinine clearance using the Modification of Diet in Renal Disease equation of 15 mL/min, hemoglobin 9.6 g/dL, total protein 11 g/dL, albumin 3.2 g/dL, immunoglobulin A (IgA) λ M protein 6.8 g/dL, total IgA 7.2 g/dL, IgG 0.4g/dL, IgM 0.03 g/dL, free κ <0.01 mg/L, free λ 1000 mg/L, serum free light chain ratio <0.01, β-2-microglobulin 4.2, viscosity 3.0, lactate dehydrogenase 200 U/L, urine protein electrophoresis: 125 mg/dL with 30% M protein, and urine immunofixation: λ light chain. Skeletal bone survey showed lytic lesions in femurs and humeri and diffusely in ribs bilaterally as well as compression fractures at T4, T6, and L2. Bone marrow biopsy revealed λ-restricted plasma cells comprising 50% of the bone marrow core. Fluorescence in situ hybridization testing on marrow showed that del 17p was present in 80% of the plasma cells. Mrs. A. is informed of the diagnosis of multiple myeloma and the need for therapy. She requests consultation with 2 of the leading world experts. However, she wants to be treated near her home and does not want treatment on a clinical trial.

The power of proteasome inhibition in multiple myeloma

INTRODUCTION

Proteasome inhibitors (PIs) are therapeutic backbones of multiple myeloma treatment, with PI-based therapies being standards of care throughout the treatment algorithm. Proteasome inhibition affects multiple critical signaling pathways in myeloma cells and interacts synergistically with mechanisms of action of other conventional and novel agents, resulting in substantial anti-myeloma activity and at least additive effects. Areas covered: This review summarizes the biologic effects of proteasome inhibition in myeloma and provides an overview of the importance of proteasome inhibition to the current treatment algorithm. It reviews key clinical data on three PIs, specifically bortezomib, carfilzomib, and ixazomib; assesses ongoing phase 3 trials with these agents; and looks ahead to the increasingly broad role of both approved PIs and PIs under investigation in the frontline and relapsed settings. Expert commentary: Progress to date with PIs in multiple myeloma has been impressive, but there remain unmet needs and challenges, as well as increasing opportunities to optimize the use of these agents. Understanding discrepancies between PIs in terms of efficacy and safety profile is a key goal of ongoing research, along with proteomics-based efforts to identify potential biomarkers of sensitivity and resistance, thereby enabling increasingly personalized treatment approaches in the future.

Therapy for relapsed multiple myeloma

Despite significant progress in our understanding and the development of novel therapies, most patients with multiple myeloma will experience relapse of their disease. Therapy of relapsed myeloma has improved due to the availability of novel agents that are highly active against the disease. However, the selection of therapy can be challenging due to the emergence of toxicities, comorbidities and frailty. In the following we discuss our approach to the treatment of the patient with relapsed myeloma.