Pomalidomide-Based Regimens for Treatment of Relapsed and Relapsed/Refractory Multiple Myeloma: Systematic Review and Meta-analysis of Phase 2 and 3 Clinical Trials

The emerging role of targeted protein degradation to treat and study cancer

The evolution of cancer treatment has provided increasingly targeted strategies both in the upfront and relapsed disease settings. Small-molecule inhibitors and immunotherapy have risen to prominence with chimeric antigen receptor T-cells, checkpoint inhibitors, kinase inhibitors, and monoclonal antibody therapies being deployed across a range of solid organ and haematological malignancies. However, novel approaches are required to target transcription factors and oncogenic fusion proteins that are central to cancer biology and have generally eluded successful drug development. Thalidomide analogues causing protein degradation have been a cornerstone of treatment in multiple myeloma, but a lack of in-depth mechanistic understanding initially limited progress in the field. When the protein cereblon (CRBN) was found to mediate thalidomide analogues' action and CRBN's neo-targets were identified, existing and novel drug development accelerated, with applications outside multiple myeloma, including non-Hodgkin's lymphoma, myelodysplastic syndrome, and acute leukaemias. Critically, transcription factors were the first canonical targets described. In addition to broadening the application of protein-degrading drugs, resistance mechanisms are being overcome and targeted protein degradation is widening the scope of druggable proteins against which existing approaches have been ineffective. Examples of targeted protein degraders include molecular glues and proteolysis targeting chimeras (PROTACs): heterobifunctional molecules that bind to proteins of interest and cause proximity-induced ubiquitination and proteasomal degradation via a linked E3 ligase. Twenty years since their inception, PROTACs have begun progressing through clinical trials, with early success in targeting the oestrogen receptor and androgen receptor in breast and prostate cancer respectively. This review explores important developments in targeted protein degradation to both treat and study cancer. It also considers the potential advantages and challenges in the translational aspects of developing new treatments. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Clinical outcomes of pomalidomide-based and daratumumab-based therapies in patients with relapsed/refractory multiple myeloma: A real-world cohort study in China

BACKGROUND

Comparative investigations evaluating the efficacy of pomalidomide-based (Pom-based) versus daratumumab-based (Dara-based) therapies in patients with relapsed/refractory multiple myeloma (RRMM) remain scarce, both in randomized controlled trials and real-world studies.

METHODS

This retrospective cohort study included 140 RRMM patients treated with Pom-based or Dara-based or a combination of pomalidomide and daratumumab (DPd) regimens in a Chinese tertiary hospital between December 2018 and July 2023.

RESULTS

The overall response rates (ORR) for Pom-based (n = 48), Dara-based (n = 68), and DPd (n = 24) groups were 57.8%, 84.6%, and 75.0%, respectively (p = 0.007). At data cutoff on August 1, 2023, the median progression-free survival (PFS) was 5.7 months (95% CI: 5.0-6.5) for the Pom-based group, 10.5 months (5.2-15.8) for the Dara-based group, and 6.7 months (4.0-9.3) for the DPd group (p = 0.056). Multivariate analysis identified treatment regimens (Dara-based vs. Pom-based, DPd vs. Pom-based) and Eastern Cooperative Oncology Group performance status (ECOG PS) as independent prognostic factors for PFS. In the subgroups of patients aged >65 years, with ECOG PS ≥2, lines of therapy ≥2, extramedullary disease or double-refractory disease (refractory to both lenalidomide and proteasome inhibitors), the superiority of Dara-based regimens over Pom-based regimens was not evident. A higher incidence of infections was observed in patients receiving Dara-based and DPd regimens (Pom-based 39.6% vs. Dara-based 64.7% vs. DPd 70.8%, p = 0.009).

CONCLUSIONS

In real-world settings, Pom-based, Dara-based, and DPd therapies exhibited favorable efficacy in patients with RRMM. Dara-based therapy yielded superior clinical response and PFS compared to Pom-based therapy.

Pomalidomide combined with dexamethasone for the treatment of relapsed/refractory multiple myeloma: a systematic review and meta-analysis

BACKGROUND

To evaluate the efficacy and safety of pomalidomide in combination treatment of relapsed/refractory multiple myeloma (RRMM).

METHODS

Published clinical trials were searched in the Cochrane Library, PubMed, EMBASE to February 2023. The literature was screened and evaluated according to the inclusion criteria, and the data were analyzed by a random effect model. Overall response rate (ORR), overall survival (OS), progression-free survival (PFS) and full grade or ≥ 3 adverse events (AEs) were the outcomes.

RESULTS

This study included 31 clinical trials, which included 4776 patients. The pooled ORR of the doublet regimens was 33.3% (95%CI: 27-39%) and the triplet regimens was 66% (95%CI: 58-74%). Among the 25 included studies, the median PFS was 8.29 months (95%CI: 7.27-9.31), and nine studies reported median OS of 19.43 months (95%CI: 14.56-24.30). In terms of safety, the most common hematologic AEs of grade ≥ 3 were neutropenia (41%) and anemia (20%); Non-hematologic AEs were pneumonia (14%) and infection/febrile neutropenia (14%).

CONCLUSIONS

Pomalidomide combined treatment regimens have shown good clinical efficacy, especially in pomalidomide + dexamethasone combined with other drugs. In terms of safety, it's important to pay attention to the likelihood of hematological adverse events when used clinically.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO: CRD42023420644.

Daratumumab-lenalidomide and daratumumab-pomalidomide in relapsed lenalidomide-exposed or refractory multiple myeloma

Daratumumab is an anti-CD38 mAb, used frequently in combination with lenalidomide and pomalidomide. No studies compared daratumumab plus lenalidomide and dexamethasone (DRd) to daratumumab plus pomalidomide and dexamethasone (DPd) in lenalidomide-exposed multiple myeloma. We identified 504 consecutive multiple myeloma patients who received daratumumab at Mayo Clinic between January 2015 and April 2019. We excluded patients who received daratumumab in the first line, received more than four lines of therapy prior to daratumumab use, did not receive lenalidomide prior to daratumumab, or had an unknown status of lenalidomide exposure, and patients who received daratumumab combinations other than DRd or DPd. We examined the impact of using DRd compared to DPd on progression-free survival (PFS) and overall survival (OS) in patients with relapsed/refractory multiple myeloma. Out of 504 patients, 162 received DRd or DPd and were included; 67 were lenalidomide-exposed and 95 were lenalidomide-refractory. DRd was used in 76 (47%) and DPd in 86 (53%) patients. In lenalidomide-exposed multiple myeloma, there was no difference in median PFS; 34.2 months [95% confidence interval (CI), 22.8-44.6] for DRd compared to 25.2 months (95% CI, 4.9-35.3) for DPd, P  = 0.2. In lenalidomide-refractory multiple myeloma, there was no difference in median PFS; 18.6 months (95% CI, 13-32) for DRd compared to 9 months (95% CI, 5.2-14.6) for DPd, P  = 0.09. No difference in median OS was observed in DRd compared to DPd. Our study shows combining daratumumab with lenalidomide in patients with prior lenalidomide use is a viable and effective treatment option.

Pomalidomide-induced lung injury: A case report

RATIONALE

Pomalidomide is an immunomodulatory imide drug used in multiple myeloma and in Kaposi sarcoma.

PATIENT CONCERNS

A 72-years-old male, treated for multiple myeloma with dexamethasone, pomalidomide and daratumumab, presented dyspnea, hypoxemia, biological inflammatory syndrome, ground glass opacities on computed tomography scan (CT-scan) and lymphocytic and eosinophilic alveolitis, with no specific cytologic or microbiological findings, 2 months after pomalidomide initiation.

INTERVENTION AND OUTCOME

Antibiotics were started after bronchoscopy. No improvement was noted in dyspnea and biological inflammatory syndrome after 5 days of treatment. Pomalidomide was then discontinued, with continuation of Daratumumab-Dexamethasone, resulting in a rapid recovery of symptoms and CT-scan anomalies. No recurrence of dyspnea was observed during the 15 months of follow-up.

DIAGNOSES

Pomalidomide-induced lung injury.

LESSONS

Pomalidomide-induced lung injury is a rare and serious adverse event that can occur early after Pomalidomide introduction. As pomalidomide use is increasing, the identification of drug toxicity as a possible cause of lung injury appears important. We report a rapid recovery of symptoms and CT-scan anomalies after pomalidomide discontinuation.

The changing landscape of relapsed and/or refractory multiple myeloma (MM): fundamentals and controversies

The increase in the number of therapeutic alternatives for both newly diagnosed and relapsed/refractory multiple myeloma (RRMM) patients has widened the clinical scenario, leading to a level of complexity that no algorithm has been able to cover up to date. At present, this complexity increases due to the wide variety of clinical situations found in MM patients before they reach the status of relapsed/refractory disease. These different backgrounds may include primary refractoriness, early relapse after completion of first-line therapy with latest-generation agents, or very late relapse after chemotherapy or autologous transplantation. It is also important to bear in mind that many patient profiles are not fully represented in the main randomized clinical trials (RCT), and this further complicates treatment decision-making. In RRMM patients, the choice of previously unused drugs and the number and duration of previous therapeutic regimens until progression has a greater impact on treatment efficacy than the adverse biological characteristics of MM itself. In addition to proteasome inhibitors, immunomodulatory drugs, anti-CD38 antibodies and corticosteroids, a new generation of drugs such as XPO inhibitors, BCL-2 inhibitors, new alkylators and, above all, immunotherapy based on conjugated anti-BCMA antibodies and CAR-T cells, have been developed to fight RRMM. This comprehensive review addresses the fundamentals and controversies regarding RRMM, and discusses the main aspects of management and treatment. The basis for the clinical management of RRMM (complexity of clinical scenarios, key factors to consider before choosing an appropriate treatment, or when to treat), the arsenal of new drugs with no cross resistance with previously administered standard first line regimens (main phase 3 clinical trials), the future outlook including the usefulness of abandoned resources, together with the controversies surrounding the clinical management of RRMM patients will be reviewed in detail.

Pomalidomide Plus Low-Dose Dexamethasone in Relapsed/Refractory Multiple Myeloma Patients: Results of the Real-World "POWERFUL" Study

The “POWERFUL” multicenter, retrospective, and prospective study investigated the effectiveness of pomalidomide plus low-dose dexamethasone (POM/LoDex) therapy in relapsed/refractory multiple myeloma in routine care in Greece. Ninety-nine eligible adult patients treated with POM/LoDex according to the approved label after having received ≥2 prior therapies, including lenalidomide and bortezomib, were consecutively enrolled between 16 November 2017 and 21 February 2019 in 18 hematology departments. Fifty patients (50.5%) started POM/LoDex as third-line treatment. During the treatment period (median: 8.3 months; range: 0.3–47.6 months), the median POM dose was 4 mg/day, and 31.3% of the patients received additional antimyeloma agents. The overall response rate was 32.3%. During a median follow-up period of 13.8 months (Kaplan–Meier estimate), the median progression-free survival (PFS) was 10.5 months (95% CI: 7.4–14.4). The PFS was not significantly different between patients receiving POM/LoDex in the third versus later line of therapy, nor between patients receiving concomitant antimyeloma therapy versus POM/LoDEx doublet. During the prospective safety data collection period (median: 7.6 months) among patients with prospective follow-up (N = 75), POM-related adverse event incidence rate was 42.7% (serious: 18.7%; grade  ≥  3 hematological POM-related adverse events: 8.0%). Only neutropenia (13.3%) was reported at a frequency ≥10%. In conclusion, in this real-world study, POM/LoDex displayed a long PFS with no new safety signals emerging.

Pomalidomide and dexamethasone in myelomatous pleural effusion

Myelomatous pleural effusion (MPE) is an uncommon clinical entity and occurs in less than 1% of all patients with multiple myeloma. MPE indicates a progression of disease, therefore is associated with a poor prognosis and estimated median survival of <3 months. Treatment of MPE is challenging, and the data regarding the role of novel agents lack in the literature. Herein, we report a relapsed IgA myeloma case of a patient presenting with MPE, who was treated with pomalidomide with a very good partial response.

Current developments in the combination therapy of relapsed/refractory multiple myeloma

INTRODUCTION

Therapy for patients with multiple myeloma has improved dramatically over the past decade following the introduction of novel agents and combinations across the disease spectrum. When relapse or refractory disease develops, non-cross-resistant drugs, most often used in multidrug regimens, have provided significant improvements in patient outcomes. Despite these advances, myeloma remains incurable and additional therapeutic approaches, based on emerging molecular and cellular biology, are moving rapidly through development phases. Approaches new to myeloma, including antibody-drug conjugates, T-cell-directed therapies, and novel small molecules, are poised to bring in the next wave of treatment.

AREAS COVERED

This review addresses recent data for the management of relapsed/refractory disease, rationale for agent and regimen selection and combinations, and options showing early promise in trials. Literature and abstracts pertaining to trial data published or presented up to 2019 are included.

EXPERT OPINION

Therapeutic strategies continue to evolve in myeloma, with the application of existing platforms (e.g., antibody-drug conjugates) to target relevant biology (e.g., B cell maturation antigen). Within the next year, there will be additional agents approved for those with advanced disease, and combinations as well as placement in sequencing will deepen responses and improve outcomes for patients.

Pomalidomide, bortezomib, and dexamethasone for multiple myeloma previously treated with lenalidomide (OPTIMISMM): outcomes by prior treatment at first relapse

In the phase 3 OPTIMISMM trial, pomalidomide, bortezomib, and dexamethasone (PVd) demonstrated superior efficacy vs bortezomib and dexamethasone (Vd) in patients with relapsed or refractory multiple myeloma previously treated with lenalidomide, including those refractory to lenalidomide. This analysis evaluated outcomes in patients at first relapse (N = 226) by lenalidomide-refractory status, prior bortezomib exposure, and prior stem cell transplant (SCT). Second-line PVd significantly improved PFS vs Vd in lenalidomide-refractory (17.8 vs 9.5 months; P = 0.0276) and lenalidomide-nonrefractory patients (22.0 vs 12.0 months; P = 0.0491), patients with prior bortezomib (17.8 vs 12.0 months; P = 0.0068), and patients with (22.0 vs 13.8 months; P = 0.0241) or without (16.5 vs 9.5 months; P = 0.0454) prior SCT. In patients without prior bortezomib, median PFS was 20.7 vs 9.5 months (P = 0.1055). Significant improvement in overall response rate was also observed with PVd vs Vd in lenalidomide-refractory (85.9% vs 50.8%; P < 0.001) and lenalidomide-nonrefractory (95.7% vs 60.0%; P < 0.001) patients, with similar results regardless of prior bortezomib or SCT. No new safety signals were observed. These data demonstrate the benefit of PVd at first relapse, including immediately after upfront lenalidomide treatment failure and other common first-line treatments.