Pomalidomide, cyclophosphamide, and dexamethasone for relapsed/refractory multiple myeloma patients in a real-life setting: a single-center retrospective study

Multiple myeloma refractory to lenalidomide: A systematic literature review of trials and real-world evidence

The growing use of frontline lenalidomide treatment in multiple myeloma (MM) is increasing the proportion of lenalidomide-refractory patients, which may limit the efficacy of subsequent lines of treatment (LOT). This systematic literature review (January 2008-October 2023) of clinical trials (CT) and real-world studies (RW) assessed treatment outcomes in adults with relapsed/refractory MM (RRMM) who were previously treated with ≥1 LOT, progressed and were lenalidomide-refractory. Medline, EMBASE and additional electronic databases were searched for articles published in English. Primary outcomes included progression-free survival (PFS), overall survival (OS) and overall/objective response rate (ORR); 24 CT and 19 RW were included. For CT, the population-weighted mean of median PFS (CT = 14) and OS (CT = 6) were shorter in the lenalidomide-refractory cohort (months: 8.8 [n = 2699] and 21.7 [n = 1066], respectively) than the intent-to-treat population (months: 13.8 [n = 5380] and 35.9 [n = 2264], respectively); the population-weighted (N = 2142) mean ORR for lenalidomide-refractory patients (CT = 18) was 56.0%. RW reported considerable variation in PFS (RW = 7), OS (RW = 8) and ORR (RW = 8); and median PFS (RW = 2; months) was lower in lenalidomide/bortezomib-refractory (5.5/5.5; n = 81/n = 25) versus lenalidomide-refractory (7.3/8.0; n = 81/n = 61) patients. These data provide evidence that clinical trials and real-world outcomes are suboptimal in lenalidomide-refractory patients with RRMM, highlighting the need to improve treatment options for this population.

Pomalidomide- and dexamethasone-based regimens in the treatment of refractory/relapsed multiple myeloma

Pomalidomide is a potent immunomodulatory agent that is currently a standard of care backbone for the treatment of multiple myeloma (MM) patients in the relapsed/refractory setting after exposure to lenalidomide and a proteasome inhibitor. The present review addresses current knowledge regarding the clinical use of pomalidomide in relapsed myeloma patients. Pomalidomide has direct myeloma cell tumoricidal effects by activating proteasomal degradation of Ikaros and Aiolos transcription factors and also indirect effects by modulation of immune responses, interaction with bone marrow stromal cells, and inhibition of angiogenesis. It is approved by regulatory authorities as doublet combination with dexamethasone but four more triplets are also approved for this setting. Many ongoing trials are evaluating the pomalidomide-dexamethasone backbone with newer anti-myeloma class agents or in quadruplet combinations. Pomalidomide-dexamethasone is currently one of the powerful tools available for use in the relapsed/refractory MM setting. Insights into the synergistic immunomodulatory effects of pomalidomide and other anti-myeloma agents and the mechanisms that overcome clonal resistance will potentially allow targeted use of triplet combinations at each relapse.

Cyclophosphamide addition to pomalidomide/dexamethasone is not necessarily associated with universal benefits in RRMM

In the backdrop of rapidly changing relapsed/refractory (RR) multiple myeloma (MM) treatment schema that mainly evolves around immunotherapies, it is easy to disregard more traditional drugs. Finding the best partner for pomalidomide, a potent third-generation immunomodulatory drug, is an important agenda we face as a community and cyclophosphamide addition has been used for outcomes augmentation. We carried out this real-world study to identify patients who will show durable response to pomalidomide and those who will benefit from cyclophosphamide addition. A total of 103 patients (57 in pomalidomide-dexamethasone [Pd] group versus 46 in pomalidomide-cyclophosphamide-dexamethasone [PCd]) were studied. They were previously treated with bortezomib (98.1%) or lenalidomide (100%) and previous lines of therapy were median 3 lines. Significantly better overall response rate (ORR) was seen in the PCd (75.6%) than Pd (41.7%) group (p = 0.001), but no differences in survival outcomes. Subgroup analysis revealed that high-risk myeloma features, poor response to lenalidomide or bortezomib had superior ORRs when cyclophosphamide was added. Also, long-term responders for pomalidomide were associated with excellent response to previous IMiD treatments. Pomalidomide-based therapy was discontinued in five patients due to intolerance or adverse events, but there was no mortality during treatment. In conclusion, we showed that pomalidomide-based treatment is still relevant and can ensure durable response in RRMM setting, especially for patients who responded well to previous lenalidomide. Addition of cyclophosphamide to Pd is associated with better ORR, and can be positively considered in fit patients with high-risk MM, extramedullary disease, and less-than-satisfactory response to previous lenalidomide treatment.

Current and Novel Alkylators in Multiple Myeloma

A large number of novel treatments for myeloma have been developed and approved; however, alkylating drugs continue to be part of standard regimens. Additionally, novel alkylators are currently being developed. We performed a non-systematized literary search for relevant papers and communications at large conferences, as well as exploiting the authors' knowledge of the field, to review the history, current use and novel concepts around the traditional alkylators cyclophosphamide, bendamustine and melphalan and current data on the newly developed pro-drug melflufen. Even in the era of targeted treatment and personalized medicine, alkylating drugs continue to be part of the standard-of-care in myeloma, and new alkylators are coming to the market.

Beyond DNA Damage: Exploring the Immunomodulatory Effects of Cyclophosphamide in Multiple Myeloma

The alkylating agent cyclophosphamide has been used in the treatment of multiple myeloma for over 60 years. At low doses, cyclophosphamide also has significant immunomodulatory activity, which can be used to modify the immunosuppressive tumor microenvironment in order to augment responses to existing therapies. Immune-mediated therapies are becoming more widespread in modern approaches to myeloma treatment. In this review, we discuss the effects cyclophosphamide has on the immune system, and how it can be used synergistically with other treatment modalities including the immunomodulatory agents, monoclonal antibodies and cellular therapies.

Pomalidomide, cyclophosphamide, and dexamethasone for elderly patients with relapsed and refractory multiple myeloma: A study of the Korean Multiple Myeloma Working Party (KMMWP-164 study)

Patients with transplant‐ineligible relapsed and refractory multiple myeloma (RRMM) have a short life expectancy, especially when they have failed both the proteasome inhibitor and immunomodulator therapies. This study aimed to assess the efficacy and safety of pomalidomide, cyclophosphamide, and dexamethasone (PCd) in elderly patients with RRMM. This phase 2 clinical trial recruited 55 elderly patients with RRMM. The patients underwent a 28‐day treatment cycle: pomalidomide (4 mg/day on days 1‐21, administered orally) and cyclophosphamide (400 mg/day on days 1, 8, and 15; administered orally) plus dexamethasone. The median (range) age of the patients was 73.3 (64‐86) years, and 8 (14.5%) patients who were ≥ 80 years old. Eight (14.5%) and 31 (56.4%) patients exhibited stage III (revised international staging system) and frail status (simplified frailty scale), respectively. The overall response rate (ORR) and clinical benefit rate (CBR) of PCd therapy were 58.2% and 72.7%, respectively. The median PFS and median overall survival (OS) were 6.90 months (95% CI, 4.7‐9.0) and 18.48 months (95% CI, 9.4‐27.6), respectively. The incidence rate of grade ≥ 3 non‐hematological toxicities was 70.8%. In particular, the incidence rate of primary infection was 45.4%, including 21.8% for pneumonia, 9.0% for sepsis, and 14.6% for febrile neutropenia. In conclusion, PCd is an effective regimen for elderly patients with RRMM who had failed both bortezomib and lenalidomide treatments, but in whom the treatment‐associated infection is the main cause of morbidity and mortality.

Clinical Benefit of Long-Term Disease Control with Pomalidomide and Dexamethasone in Relapsed/Refractory Multiple Myeloma Patients

Background: We retrospectively analysed relapsed/refractory MM (RRMM) patients treated with pomalidomide and dexamethasone (PomaD) either in real life, or previously enrolled in an interventional (STRATUS, MM-010) or currently enrolled in an observational study (MM-015) to provide further insights on safety and tolerability and clinical efficacy. Methods: Between July 2013 and July 2018, 76 RRMM patients (including 33 double refractory MM) received pomalidomide 4 mg daily given orally on days 1–21 of each 28-day cycle, and dexamethasone 40 mg weekly (≤75 years) or 20 mg weekly for patients aged > 75 years. In nine patients a third agent was added to increase the response: Cyclophosphamide (in two fit patients) or clarithromycin (in seven frail patients). Patients received subcutaneous filgrastim as part of the prophylaxis regimen for neutropenia. Results: A median number of six (range 2–21) PomaD cycles were given. The regimen was well tolerated with grade 3–4 haematological and non-haematological adverse events in 39 (51%) and 25 (33%) patients, respectively. In patients who developed serious AE, pomalidomide dose reduction (11%, 14%) or definitive discontinuation (18%, 23%) were applied. All patients have been evaluated for response within the first two cycles. The disease control rate (DCR), i.e., those patients that had a response equal or better than stable disease (≥ SD), was high (89%), with 44% overall response rate (ORR) after six cycles. The achieved best responses were complete remission (CR, 5%), very good partial remission (VGPR, 4%), partial remission (PR, 35%), minimal response (MR, 7%), and stable disease (SD, 38%). After a median follow up of 19.6 months, median progression free survival was 9.4 months, and overall survival (OS) was 19.02 months. Univariate analysis showed that double refractory patients, or who received more than three previous lines had shorter PFS. At 18 months, regardless of the depth of response, patients with a disease control of at least six months, defined as maintenance of a best clinical and/or biochemical response to treatment for almost six months, had prolonged PFS (35.3% versus 20.6%, p = 0.0003) and OS (81.2% versus 15.9%, p < 0.0001) Conclusions: Our findings indicate that PomaD is a safe and well-tolerated regimen in real-life, associated with prolonged PFS and OS with acceptable toxicity. Moreover, Pd induced disease control in most intensively pre-treated patients and some of them achieved longer PFS than that obtained with the previous treatment.

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.

Update on elotuzumab for the treatment of relapsed/refractory multiple myeloma: patients' selection and perspective

Monoclonal antibodies (mAbs) targeting antigens expressed by plasma cells demonstrated major clinical activity in multiple myeloma patients and therefore became a new major class of drug for these patients. Elotuzumab is a humanized mAb targeting the cell surface signaling lymphocytic activation molecule family member 7, a glycoprotein highly expressed on plasma cells, that is the second mAb approved for the treatment of myeloma patients. The mechanism of action of elotuzumab includes natural killer cell (NK) mediated antibody-dependent cellular cytotoxicity and direct activation of NK-cells. Elotuzumab has been approved in combination with lenalidomide and dexamethasone (Elo-Rd) and pomalidomide and dexamethasone (Elo-Pd) for the treatment of relapsed myeloma patients. The present review will focus on elotuzumab, providing a summary of the mechanism of action, efficacy and safety and taking into consideration patients’ selection.