Pre-Clinical Assessment of SAR442257, a CD38/CD3xCD28 Trispecific T Cell Engager in Treatment of Relapsed/Refractory Multiple Myeloma

Current treatment strategies for multiple myeloma (MM) are highly effective, but most patients develop relapsed/refractory disease (RRMM). The anti-CD38/CD3xCD28 trispecific antibody SAR442257 targets CD38 and CD28 on MM cells and co-stimulates CD3 and CD28 on T cells (TCs). We evaluated different key aspects such as MM cells and T cells avidity interaction, tumor killing, and biomarkers for drug potency in three distinct cohorts of RRMM patients. We found that a significantly higher proportion of RRMM patients (86%) exhibited aberrant co-expression of CD28 compared to newly diagnosed MM (NDMM) patients (19%). Furthermore, SAR442257 mediated significantly higher TC activation, resulting in enhanced MM killing compared to bispecific functional knockout controls for all relapse cohorts (Pearson's r = 0.7). Finally, patients refractory to anti-CD38 therapy had higher levels of TGF-β (up to 20-fold) compared to other cohorts. This can limit the activity of SAR442257. Vactoserib, a TGF-β inhibitor, was able to mitigate this effect and restore sensitivity to SAR442257 in these experiments. In conclusion, SAR442257 has high potential for enhancing TC cytotoxicity by co-targeting CD38 and CD28 on MM and CD3/CD28 on T cells.

Safety and efficacy of belantamab mafodotin with pembrolizumab in patients with relapsed or refractory multiple myeloma

BACKGROUND

Belantamab mafodotin (belamaf) has shown promising antimyeloma activity in relapsed or refractory multiple myeloma (RRMM) as a single agent. It was hypothesized that its multimodal activity may be enhanced by programmed cell death protein 1 pathway inhibition and activation of T cell-mediated antitumor responses. This study investigated the efficacy and safety of belamaf with pembrolizumab in patients with RRMM.

METHODS

DREAMM-4 (NCT03848845) was an open-label, single-arm, phase 1/2 study divided into dose-escalation (part 1) and dose-expansion (part 2) phases. Patients were ≥18 years old with ≥3 prior lines of therapy including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 agent. Patients received belamaf (2.5 or 3.4 mg/kg, part 1; 2.5 mg/kg, part 2) and 200 mg pembrolizumab for ≤35 cycles.

RESULTS

Of 41 enrolled patients, 34 (n = 6 part 1, n = 28 part 2) who received 2.5 mg/kg belamaf plus pembrolizumab were included in this final analysis. Sixteen patients (47%) achieved an overall response. Minimal residual disease negativity was achieved in three of 10 patients who had very good partial response or better. Five of eight patients who had prior anti-B-cell maturation antigen therapy achieved partial response or better, including two who had B-cell maturation antigen-refractory disease. Common grade ≥3 adverse events were keratopathy (38%) and thrombocytopenia (29%). Despite belamaf-related ocular events, quality-of-life measures remained stable over time. No new safety signals were observed.

CONCLUSIONS

The results of DREAMM-4 demonstrated clinical activity and a favorable safety profile of belamaf plus pembrolizumab in patients with RRMM. This trial is registered at www.

CLINICALTRIALS

gov as NCT03848845.

Selinexor for the treatment of patients with relapsed or refractory multiple myeloma

OBJECTIVE

Multiple myeloma cells resist standard therapies due to overexpression of the transport protein, exportin 1. Selinexor is a novel drug that targets the Exportin 1 protein in these cells.

DATA SOURCE

A comprehensive search was done, and data showing the efficacy and safety of selinexor in relapsed/refractory multiple myeloma was collected using PubMed, Google Scholar, and clincialtrials.gov.

DATA SUMMARY

Results from the clinical trials STORM, BOSTON, and STOMP were included. Parts I and II of the STORM trial revealed a progression-free survival (PFS) of 4.7 and 3.7 months, a median duration of response of 6.2 and 4.4 months, and an overall survival of 7.3 and 8.4 months, respectively. BOSTON trial's SVd arm (selinexor, bortezomib, and dexamethasone) had a median follow-up period of 13.2 months and an mPFS of 13.93 months. The Vd arm (bortezomib and dexamethasone) had a median follow-up duration of 16.5 months and an mPFS of 9.46 months. The STOMP trial is still active and has limited data available. The SKd arm (selinexor, carfilzomib, and dexamethasone) reported an overall response rate of 66.7% in patients with triple refractory multiple myeloma, and 82% in patients with high-risk cytogenetics. The SPd arm (selinexor, pomalidomide, and dexamethasone) shows an overall response rate of 54.30% in pomalidomide naïve-nonrefractory, 35.70% in pomalidomide refractory and 60% in those dosed at RP2D. SRd arm (selinexor, lenalidomide, and dexamethasone) shows an overall response rate of 91.7% in lenalidomide naïve and 12.5% in lenalidomide refractory patients. SVd (selinexor, bortezomib, and dexamethasone) arm reported an overall response rate of 63% in all patients while the SDd arm (selinexor, daratumumab, and dexamethasone) showed an overall response rate of 73%.

CONCLUSION

To improve the outcome of patients with relapsed/refractory multiple myeloma, it is critical to develop new therapies, assess potential therapeutic synergies, and overcome drug resistance by determining the efficacy of multiple myeloma therapies across multiple disease subgroups.

Refractory multiple myeloma: Count refractory drugs, not lines of treatment!

Current approved immunotherapeutic agents such as CART cells are limited to patients with at least 3 or even 4 prior lines of treatment. However more and more patients become refractory to standard regimens in earlier lines. Mohyuddin et al. examined the inclusion criteria of current immunotherapeutic trials in myeloma and propose a change to put more emphasis on refractoriness to 3 or more agents and to omit a required number of lines of therapy in current and future protocols. Commentary on: Mohyuddin et al. Inclusion criteria of currently enrolling T-cell engaging trials in multiple myeloma: Should we be focusing on lines of prior therapy? Br J Haematol 2022 (Online ahead of print). doi: 10.1111/bjh.18755.

Carfilzomib for relapsed and refractory multiple myeloma

Although the prognosis of multiple myeloma (MM) patients has dramatically improved during recent years, virtually all patients eventually develop relapsed refractory disease. Several new therapeutics have been developed in the last few years, including carfilzomib, a second-generation proteasome inhibitor (PI) that has been approved by the US Food and Drug Administration (FDA) in the setting of relapsed and/or refractory MM, as a single agent with or without dexamethasone, and in combination with lenalidomide in 2012 and 2015, respectively. Other promising combinations with carfilzomib are being investigated. Carfilzomib has shown superiority over the first-generation PI bortezomib on both efficacy and toxicity. In particular, profoundly lower incidence in polyneuropathy compared to bortezomib has been described. However, carfilzomib has a different toxicity profile, with more cardiovascular adverse events. Therefore, caution should be taken with the use of carfilzomib for elderly and cardiovascularly compromised patients. The once-weekly administration of carfilzomib, recently approved by the FDA in combination with dexamethasone, will lead to a lower burden for the patient and caregivers compared to the twice-weekly schemes that were routinely used until recently. This review has a focus on clinical trial data that has led to drug approval, as well as new promising combination studies, and provides advice for treating physicians who are now prescribing this drug to patients.

Therapeutic monoclonal antibodies in combination with pomalidomide can overcome refractoriness to both agents in multiple myeloma: A case-based approach

In multiple myeloma (MM), the synergy between immunomodulatory drugs (IMiDs) and monoclonal antibodies (MABs) has been demonstrated in several pivotal trials. However, disease refractory to either class of compounds remains a major therapeutic challenge. We here report on 3 heavily pretreated MM patients who were refractory to pomalidomide as well as to MABs against CD38 (daratumumab) or CD20 (rituximab), respectively, but who responded to retreatment with the same agents in combination. Responses were durable with PFS of 7, 10 (ongoing), and 30 months from initiation of combination treatment. The combination of IMiDs with MABs directed against MM cell surface antigens can overcome refractoriness to both agents.

Pomalidomide in heavily pretreated refractory multiple myeloma: a case report

We present the case of a 70-year-old man diagnosed with multiple myeloma in 2008, who after four therapy lines initiated a fifth-line treatment with pomalidomide (4 mg orally, days 1-21 of a 28-day cycle) and low-dose dexamethasone (40 mg weekly orally). The patient was treated with pomalidomide for almost 2 years achieving a complete remission after 12 cycles. Complete remission was maintained for 9 months. This case illustrates the potential of pomalidomide plus low-dose dexamethasone to overcome multiple myeloma refractoriness inducing a quick and very prolonged remission.

Management of multiple myeloma: the impact of ixazomib's approval in Canada

Donna E Reece speaks to Laura Dormer, Commissioning Editor: Dr Donna E Reece is a Professor of Medicine and Director of the Program for Multiple Myeloma and Related Diseases in the Department of Medical Oncology and Hematology at Princess Margaret Hospital/University of Toronto. She earned a Bachelor of Arts degree at the University of Texas, Austin, and graduated as valedictorian with a medical degree from Baylor College of Medicine, Houston, Texas. She completed an internship in Internal Medicine at the University of Colorado Affiliated Hospitals, a residency and Chief Residency in Internal Medicine at Jewish Hospital, St Louis, and a Fellowship in Hematology/Oncology at Barnes Hospital, Washington University, St Louis, Missouri. She was a fellow and later a leukemia/stem cell transplant staff physician at Vancouver General Hospital/University of British Columbia for over 10 years. She then served as Director of the Outpatient Leukemia/Stem Cell Transplant Program, and later interim director, of the Blood and Marrow Transplant Program of the Markey Cancer Center at the University of Kentucky, Lexington, Kentucky until her appointment to Princess Margaret Hospital in Toronto in 2001. Dr Reece received the David and Molly Bloom Chair in Myeloma Research in 2009. She is currently the co-chair of the Multiple Myeloma Clinical Trials Group of the National Cancer Institute of Canada, member of the Scientific Advisory Board of the International Myeloma Foundation, and member of the Project Review Committee of the MMRC (Multiple Myeloma Research Consortium). She is also the Chief Medical Officer of the Myeloma Canada Research Network and serves on the board of directors of Myeloma Canada. Her career focus has been in the areas of hematopoietic stem cell transplantation, lymphoid malignancies and plasma cell dyscrasias. She has published numerous articles in these areas.

Phase I-II trial of oral cyclophosphamide, prednisone and lenalidomide for the treatment of patients with relapsed and refractory multiple myeloma

This single institution, open label Phase I-II dose escalation trial evaluated the safety and efficacy of the combination of lenalidomide (Revlimid®), cyclophosphamide and prednisone (CPR) in patients with relapsed/refractory multiple myeloma. The maximal administered dose of CPR consisted of cyclophosphamide 300 mg/m(2) on day 1, 8, and 15, lenalidomide 25 mg on d 1-21 and prednisone 100 mg every other day in a 28-d cycle. Between November 2007 and June 2009, 32 patients were entered in cohorts of three at three dose levels. The median age was 64 years, 59% were male, with a median two prior regimens. Responding patients could stay on treatment until progression. The full-dose CPR regimen produced no dose-limiting toxicity and was delivered for a median of 16 months (3·5-65 months) with acceptable safety and tolerance. The overall response rate (≥ partial response) was 94% at a median follow up of 28 months. The median progression-free survival was 16·1 months [95% confidence interval (CI); 10·9-22·5 months], while the median overall survival was 27·6 months (95% CI; 16·8-36·6 months). Only the beta-2 microglobulin level at protocol entry correlated with a better survival (P = 0·047). These observations compare favourably with other 2- and 3- drug combinations for relapsed/refractory myeloma, and suggest that CPR should be evaluated further in the setting of relapsed/refractory disease, or in newly diagnosed patients.