Efficacy of retreatment with immunomodulatory drugs and proteasome inhibitors following daratumumab monotherapy in relapsed and refractory multiple myeloma patients

A Phase I Trial Evaluating the Addition of Lenalidomide to Patients with Relapsed/Refractory Multiple Myeloma Progressing on Ruxolitinib and Methylprednisolone

BACKGROUND

Ruxolitinib (RUX), an orally administered selective Janus kinase 1/2 inhibitor, has received approval for the treatment of myelofibrosis, polycythemia vera, and graft-versus-host disease. We have previously demonstrated the anti-multiple myeloma effects of RUX alone and in combination with the immunomodulatory agent lenalidomide (LEN) and glucocorticosteroids both pre-clinically and clinically.

OBJECTIVE

This study aims to evaluate whether LEN can achieve clinical activity among patients with multiple myeloma progressing on the combination of RUX and methylprednisolone (MP).

METHODS

In this part of a phase I, multicenter, open-label study, we evaluated the safety and efficacy of RUX and MP for patients with multiple myeloma with progressive disease who had previously received a proteasome inhibitor, LEN, glucocorticosteroids, and at least three prior regimens; we also determined the safety and efficacy of adding LEN at the time of disease progression from the initial doublet treatment. Initially, all subjects received oral RUX 15 mg twice daily and oral MP 40 mg every other day. Those patients who developed progressive disease according to the International Myeloma Working Group criteria then received LEN 10 mg once daily on days 1-21 within a 28-day cycle in addition to RUX and MP, which were administered at the same doses these patients were receiving at the time progressive disease developed.

RESULTS

Twenty-nine subjects (median age 64 years; 18 [62%] male) were enrolled in this part of the study and initially received the two-drug combination of RUX and MP. The median number of prior therapies was six (range 3-12). The overall response rate from this two-drug combination was 31% and the clinical benefit rate was 34%. The best responses were 1 very good partial response, 8 partial responses, 1 minor response, 12 stable disease, and 7 progressive disease. The median progression-free survival was 3.5 months (range  0.5-36.2 months). The median time to response was 3.0 months. The median duration of response was 12.5 months (range 2.8-36.2 months). Twenty (69%) patients who showed progressive disease had LEN added to RUX and MP; all patients had prior exposure to LEN and all but one patient was refractory to their last LEN-containing regimen. After the addition of LEN, the overall response rate was 30% and the clinical benefit rate was 40%. The best responses of patients following the addition of LEN were 2 very good partial responses, 4 partial responses, 2 minor responses, 8 stable disease, and 4 progressive disease. The median time to response was 2.6 months (range 0.7-15.0 months). The median duration of response was not reached. The median progression-free survival following the addition of LEN was 3.5 months (range 0.3-25.9 months).

CONCLUSIONS

For patients with multiple myeloma, treatment with RUX and MP is effective and well tolerated, and LEN can be used to extend the benefit of this RUX-based treatment.

CLINICAL TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov, NCT03110822, and is ongoing.

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.

Continuous low-dose cyclophosphamide plus prednisone in the treatment of relapsed and refractory multiple myeloma with severe complications

Background/objective

We retrospectively analyzed the effective and safety of continuous low-dose cyclophosphamide combined with prednisone (CP) in relapsed and refractory multiple myeloma (RRMM) patients with severe complications.

Methods

A total of 130 RRMM patients with severe complications were enrolled in this study, among which 41 patients were further given bortezomib, lenalidomide, thalidomide or ixazomib on the basis of CP regimen (CP+X group). The response to therapy, adverse events (AEs), overall survival (OS) and progression-free survival (PFS) were recorded.

Results

Among the 130 patients, 128 patients received therapeutic response assessment, with a complete remission rate (CRR) and objective response rate (ORR) of 4.7% and 58.6%, respectively. The median OS and PFS time were (38.0 ± 3.6) and (22.9±5.2) months, respectively. The most common AEs were hyperglycemia (7.7%), pneumonia (6.2%) and Cushing's syndrome (5.4%). In addition, we found the pro-BNP/BNP level was obviously decreased while the LVEF (left ventricular ejection fraction) was increased in RRMM patients following CP treatment as compared with those before treatment. Furthermore, CP+X regimen further improved the CRR compared with that before receiving the CP+X regimen (24.4% vs. 2.4%, P=0.007). Also, both the OS and PFS rates were significantly elevated in patients received CP+X regimen following CP regimen as compared with the patients received CP regimen only.

Conclusion

This study demonstrates the metronomic chemotherapy regimen of CP is effective to RRMM patients with severe complications.

Predictive role of absolute lymphocyte count in daratumumab-treated patients with relapsed/ refractory multiple myeloma

BACKGROUND/AIMS

Daratumumab has shown an encouraging antitumor effect in patients with multiple myeloma (MM), and was known to alter the immune properties by off-targeting immunosuppressive cells. Here, we aimed to evaluate the change in absolute lymphocyte count (ALC) as a surrogate marker for predicting survival outcomes of patients treated with daratumumab.

METHODS

Between 2018 and 2021, the medical records of patients with relapsed/refractory MM (RRMM) treated with daratumumab monotherapy at 10 centers in South Korea were reviewed. We collected the ALC data at pre-infusion (D0), day 2 after the first infusion (D2), and prior to the third cycle of daratumumab therapy (D56).

RESULTS

Fifty patients who were administered at least two cycles of daratumumab were included. Overall response rate was 54.0% after two cycles of daratumumab treatment. On D2, almost all patients experienced a marked reduction in ALC. However, an increase in ALC on D56 (ALCD56) was observed in patients with non-progressive disease, whereas failure of ALC recovery was noted in those with progressive disease. Patients with ALCD56 > 700/μL (n = 39, 78.0%) had prolonged progression- free survival (PFS) and overall survival (OS) than those with ALCD56 ≤ 700/μL (median PFS: 5.8 months vs. 2.6 months, p = 0.025; median OS: 24.1 months vs. 6.1 months, p = 0.004). In addition, ALCD56 >700/μL was a significant favorable prognostic factor for PFS (hazard ratio [HR], 0.22; p = 0.003) and OS (HR, 0.23; p = 0.012).

CONCLUSION

Increase in ALC during daratumumab treatment was significantly associated with prolonged survival outcomes in patients with RRMM. The ALC value can predict clinical outcomes in patients treated with daratumumab.

Daratumumab Monotherapy for Heavily Pre-treated and Refractory Myeloma: Results from a UK Multicentre Real World Cohort

Daratumumab is the first anti-CD38 targeting monoclonal antibody approved as monotherapy in multiply relapsed myeloma patients who progressed following prior treatment with proteasome inhibitors (PIs) and immunomodulatory agents (IMiDs). We present real world data on the efficacy of single agent daratumumab in a cohort of 55 multiply relapsed patients treated in the UK.The median age was 72 years, the majority (96%) received ≥ 3 previous lines of treatment; 54.5% were PI-refractory, 76.4% were IMiD-refractory and 47.2% were double refractory; 20% of patients had high-risk (HR) disease.The overall response rate was 49%. After a median follow up of 9.2 months, the median progression-free survival (PFS) for the total cohort was 5.1 months. Patients who achieved a partial response or better (≥PR) demonstrated a significantly longer PFS compared to those with <PR; 9.8 versus 2.7 months, p < 0.001. Double-refractory patients had an inferior PFS compared to single-refractory patients; 2.7 versus 7.4 months, p = 0.084. High-risk disease was associated with significantly shorter PFS compared to standard-risk (SR); 2.3 versus 6.7 months, p = 0.001. The median overall survival (OS) was 15.9 months. Despite a relatively short PFS seen in the double-refractory and high-risk patients; a favourable median overall survival of 12.9 months was achieved in these groups. Patients who achieved ≥PR, those with a previous objective response to PIs or IMiDs and those with SR disease, all benefited from a significantly longer OS which was not reached. A clear benefit in survival is encouraging in this setting of unmet clinical need and limited treatment options.

Treatment patterns and overall survival of patients with double-class and triple-class refractory multiple myeloma: a US electronic health record database study

Patients with relapsed/refractory multiple myeloma (RRMM) resistant to multiple drug classes remain a high unmet need population. This longitudinal retrospective cohort study assessed real-world treatment patterns and outcomes in adults with RRMM. Patients who had three or more prior lines of therapy including a proteasome inhibitor (PI) and an immunomodulatory agent (double-exposed) were further categorized as refractory to a PI and an immunomodulatory agent (double-class refractory, n = 381) or additionally to an anti-CD38 monoclonal antibody (triple-class refractory, n = 173). Treatment options are limited for patients with double-class or triple-class refractory disease. Retreatment is a part of standard of care. Bortezomib and lenalidomide had the highest retreatment rates among double-class and triple-class refractory patients. Survival outcomes remain poor among RRMM patients with median overall survival (OS) of 22.3 and 11.6 months for double-class refractory and triple-class refractory patients, respectively. This study highlights the need for novel efficacious therapies in this heavily pretreated RRMM population.

Targeting CD38 in Neoplasms and Non-Cancer Diseases

Simple Summary

CD38 remains an interesting target for anticancer therapy. Its relatively high abundance in neoplasms and crucial impact on NAD+/cADPR metabolism and the activity of T cells allows for changing the immune response in autoimmune diseases, neoplasms, and finally the induction of cell death. Antibody-dependent cell cytotoxicity is responsible for cell death induced by targeting the tumor with anti-CD38 antibodies, such as daratumumab. A wide range of laboratory experiments and clinical trials show an especially promising role of anti-CD38 therapy against multiple myeloma, NK cell lymphomas, and CD19- B-cell malignancies. More studies are required to include more diseases in the therapeutic protocols involving the modulation of CD38 activity.

Abstract

CD38 is a myeloid antigen present both on the cell membrane and in the intracellular compartment of the cell. Its occurrence is often enhanced in cancer cells, thus making it a potential target in anticancer therapy. Daratumumab and isatuximab already received FDA approval, and novel agents such as MOR202, TAK079 and TNB-738 undergo clinical trials. Also, novel therapeutics such as SAR442085 aim to outrank the older antibodies against CD38. Multiple myeloma and immunoglobulin light-chain amyloidosis may be effectively treated with anti-CD38 immunotherapy. Its role in other hematological malignancies is also important concerning both diagnostic process and potential treatment in the future. Aside from the hematological malignancies, CD38 remains a potential target in gastrointestinal, neurological and pulmonary system disorders. Due to the strong interaction of CD38 with TCR and CD16 on T cells, it may also serve as the biomarker in transplant rejection in renal transplant patients. Besides, CD38 finds its role outside oncology in systemic lupus erythematosus and collagen-induced arthritis. CD38 plays an important role in viral infections, including AIDS and COVID-19. Most of the undergoing clinical trials focus on the use of anti-CD38 antibodies in the therapy of multiple myeloma, CD19- B-cell malignancies, and NK cell lymphomas. This review focuses on targeting CD38 in cancer and non-cancerous diseases using antibodies, cell-based therapies and CD38 inhibitors. We also provide a summary of current clinical trials targeting CD38.

Efficacy and safety of daratumumab combined with all-trans retinoic acid in relapsed/refractory multiple myeloma

The efficacy of daratumumab depends partially on CD38 expression on multiple myeloma (MM) cells. We have previously shown that all-trans retinoic acid (ATRA) upregulates CD38 expression and reverts daratumumab-resistance ex vivo. We therefore evaluated the optimal dose, efficacy, and safety of daratumumab combined with ATRA in patients with daratumumab-refractory MM in a phase 1/2 study (NCT02751255). In part A of the study, 63 patients were treated with daratumumab monotherapy. Fifty patients with daratumumab-refractory MM were subsequently enrolled in part B and treated with daratumumab (reintensified schedule) combined with ATRA until disease progression. The recommended phase 2 dose of ATRA in combination with daratumumab was defined as 45 mg/m2. At this dose, the overall response rate (ORR) was 5%, indicating that the primary endpoint (ORR ≥15%) was not met. However, most patients (66%) achieved at least stable disease. After a median follow-up of 43 months, the median progression-free survival (PFS) for all patients was 2.8 months. Patients who previously achieved at least a partial response or minimal response/stable disease with prior daratumumab monotherapy had a significantly longer PFS compared with patients who immediately progressed during daratumumab as single agent (median PFS 3.4 and 2.8 vs 1.3 months). The median overall survival was 19.1 months. The addition of ATRA did not increase the incidence of adverse events. Flow cytometric analysis revealed that ATRA temporarily increased CD38 expression on immune cell subsets. In conclusion, the addition of ATRA and reintensification of daratumumab had limited activity in patients with daratumumab-refractory MM, which may be explained by the transient upregulation of CD38 expression. This trial was registered at www.clinicaltrials.gov as #NCT02751255.

Daratumumab provides a survival benefit in relapsed and refractory Multiple Myeloma, independent of baseline clinical characteristics: A meta-analysis

Daratumumab was approved in patients with relapsed or refractory multiple myeloma (MM) who previously received proteasome inhibitors or immunomodulatory drugs. However, the efficacy and safety of the addition of daratumumab in subpopulations of patients with relapsed or refractory MM is still unknown. We systematically searched MEDLINE, EMBASE, and Cochrane for randomized controlled trials (inception to September 2020). All phase 3 randomized controlled trials (RCTs) which were conducted in patients with relapsed or refractory MM and compared the efficacy or safety with the addition of daratumumab versus control were adopted. Three studies including 1497 patients met our criteria. The addition of daratumumab increased the rates of overall response (RR 1.21, 95% CI 1.15-1.28, p < .001), complete response or better (RR 2.43, 95% CI 2.00-2.96, p < .001), very good partial response or better (RR 1.63, 95% CI 1.48-1.80, p < .001) compared with those with control. No clear evidence of heterogeneity was found in comparisons of progression-free survival obtained from subsets of studies grouped by the age of participant, ISS disease stage, type of measurable MM, the level of baseline renal function, cytogenetic profile. The results showed progression-free survival benefit was consistent between the treatment groups regarding previous clinical therapy information. Patients receiving daratumumab had higher risks of lymphopenia and infusion-related reactions of any grade and grade 3 or 4. In conclusions, this study provides a clear proof of beneficial effects of daratumumab-based therapy in patients with relapsed or refractory MM with an acceptable safety profile. The progression-free survival benefit was consistent regardless of patient's baseline characteristics or previous therapy agents.

Monoclonal Antibodies and Antibody Drug Conjugates in Multiple Myeloma

Multiple myeloma is the second most common hematologic malignancy. Current treatment strategies are mainly based on immunomodulatory drugs, proteasome inhibitors or combination of both. Novel agents added to these backbone treatments represent a promising strategy in treatment of newly diagnosed as well as relapsed and refractory multiple myeloma patients. In this respect, the incorporation of monoclonal antibodies into standard-of-care regimens markedly improved prognosis of myeloma patients during the last years. More specifically, monoclonal anti-CD38 antibodies, daratumumab and isatuximab, have been implemented into treatment strategies from first-line treatment to refractory disease. In addition, the monoclonal anti-SLAM-F7 antibody elotuzumab in combination with immunomodulatory drugs has improved the clinical outcomes of patients with relapsed/refractory disease. Belantamab mafodotin is the first approved antibody drug conjugate directed against B cell maturation antigen and is currently used as a monotherapy for patients with advanced disease. This review focuses on clinical efficacy and safety of monoclonal antibodies as well as antibody drug conjugates in multiple myeloma.

Daratumumab as Single Agent in Relapsed/Refractory Myeloma Patients: A Retrospective Real-Life Survey

Background

The anti-CD38 monoclonal antibody daratumumab is approved as a single agent for the treatment of patients with relapsed/refractory multiple myeloma (RRMM) who received at least three prior lines of therapy, including proteasome inhibitor and immunomodulatory agent. A retrospective multicentric study was designed to evaluate feasibility, tolerability, and efficacy of daratumumab in monotherapy in RRMM.

Methods

This study included 44 consecutive RRMM patients that underwent daratumumab monotherapy after a median number of four prior therapies (range 2–9). Patients were treated in seven Sicilian centers, as part of Sicilian Myeloma Network and three Calabrian centers outside of controlled clinical trials from August 2016 through July 2020.

Results

The regimen was well tolerated with few grade 3–4 haematological and rare non-haematological adverse events, such as pneumonia. Definitive discontinuation was due to disease progression in 25 (57%) patients. Since three patients did not complete at least one full cycle, a total of 41 patients was evaluated for response. Overall response rate was 37%, and the disease control rate (stable disease or better) was high (73%). The best achieved responses within 6 months were very good partial remission or better (27%), partial remission (10%), minimal response (14%) and stable disease (22%). After a median follow up of 7.8 months, median progression free survival (PFS) was 7.2 months and overall survival (OS) 7.8 months. Univariate analysis showed that patients with PR or better after 6 months of therapy had longer median PFS and OS (respectively 29.5 vs 3.6 months, p=0.0001 and 30.6 vs 3.9 months p=0.0001), confirmed by multivariate analysis. Furthermore, standard cytogenetic risk and biochemical relapse type had prolonged median PFS, but not OS (respectively unreached vs 2.6, p=0.03 and 23.9 vs 6.2, p=0.05) in both univariate and multivariate analysis. Additionally, univariate analysis showed that patients treated with carfilzomib-lenalidomide-dexamethasone prior to daratumumab had significantly shorter PFS compared to pomalidomide-dexamethasone (3.4 months vs 9.3 months, p=0.03), that multivariate analysis failed to confirm.

Conclusions

Our findings indicate that daratumumab as single agent is safe and well-tolerated regimen in real-life, associated to prolonged PFS and OS in responding patients. No new safety signals were identified.

Real-World Outcome in the pre-CAR-T Era of Myeloma Patients Qualifying for CAR-T Cell Therapy

Background

CAR-T cell therapy is likely to be introduced starting from 2021 in patients with relapsed/refractory myeloma (r/r MM) in Europe. In order to qualify for commercial CAR-T treatment, it is assumed that r/r MM patients will have to be exposed to at least three lines of previous treatments including lenalidomide, bortezomib and anti-CD38 treatment. However, the outcome of this particular subgroup of r/r MM patients is largely unknown whereas this knowledge is crucial to estimate the possible benefit of eventual CAR-T treatment.

Methods

In this non-interventional, retrospective single-center study, we analyzed all subsequent r/r MM patients treated between 01/2016 (when anti-CD38 treatment was commercially introduced in Switzerland) and 04/2020 at the University Hospital of Bern. Patients were eligible for the study if they had received at least three lines of treatment including one proteasome inhibitor (PI), one immunomodulatory drug (IMID) and one anti-CD38 antibody, and if they were in need of subsequent treatment and effectively received further lines of treatment.

Results

Among 56 patients fulfilling the criteria of at least three lines of treatment including PI, IMID and anti-CD38 treatment, only 34 (60%) effectively received subsequent further therapy. This suggests that 40% of r/r MM patients never receive additional treatment after at least three lines of treatment including PI, IMID and anti-CD38 treatment. For patients receiving further treatment, the median number of previous lines of treatment was 4.5 (range 2–12), including autologous stem cell transplantation in 31 (91%) patients. 13 (37%) patients were penta-refractory. The most frequently used treatment options were IMID/dexamethasone treatment in 11 (32%) patients, followed by PI/dexamethasone in 10 (29%) patients. 21 (62%) patients received two or more additional lines of therapy. The median PFS was 6.6 months (range 0–36.6 months), the median TTNT was 7.5 months (range 1.4–24.5 months) and the median OS was 13.5 months, (range 0.1–38 months) for the first subsequent treatment. The overall response rate (ORR) to the first subsequent treatment was 41%, with a median duration of the response of 5 months (range 1–37 months). 12% of the patients achieved VGPR or better, with a median duration of response of 8 months (range 3–37 months).

Conclusions

Myeloma patients refractory after at least three lines of anti-CD38/PI/IMID treatment have a poor prognosis with a PFS of 6.6 months and OS of 13.5 months. These data may serve as reference to compare the potential benefit of CAR-T treatment in this group of myeloma patients when available in the near future.

DNA methylation inhibition in myeloma: Experience from a phase 1b study of low-dose continuous azacitidine in combination with lenalidomide and low-dose dexamethasone in relapsed or refractory multiple myeloma

The DNA methyltransferase inhibitor azacytidine (aza) may reactivate pathways associated with plasma cell differentiation, cell cycle control, apoptosis, and immune recognition and thereby restore sensitivity to lenalidomide (len) and dexamethasone (dex) in relapsed and/or refractory multiple myeloma (RRMM). We aimed to develop an aza regimen that reaches epigenetically active levels 8 times in 28 days with less bone marrow toxicity than the myeloid malignancy standard of 7 consecutive doses to enable safe combination with len. Aza was escalated from 30 mg/m² once a week up to a predefined maximum of 50 mg/m² twice a week in combination with GFR-adjusted len (≥ 60 mL/min: 25 mg, 3059 mL/min: 10 mg) day 1 to 21 every 28 days and dex 40 mg once a week followed by a limited expansion study to a total N of 23 at the highest tolerated dose. Fifty-one patients (pts) with RRMM were screened, 42 were treated and 41 were evaluable for response based on at least 1 response assessment or progression after treatment start. The median number of prior lines of therapy was 5 (1-11) and 81% (34) were refractory to len and/or pomalidomide (pom). Two DLTs occurred in different cohorts, 1 neutropenic fever in 1/6 pts on the aza 40 mg/m² twice a week GFR ≥ 60 mL/min cohort and 1 GGT elevation in 1/6 pts on the aza 50 mg/m² GFR 30-59 mL/min cohort. An MTD was not reached and aza 50 mg/m² SC twice a week was chosen for the expansion study. At least possibly related Grade 3/4 AEs occurred in 28 pts (67%) with the following in > 1 pt: neutropenia (N = 16, 38%), anemia (N = 6, 14%), lymphopenia (N = 5, 12%), thrombocytopenia (N = 4, 10%), leukopenia (N = 4, 10%), febrile neutropenia (N = 4, 10%), fatigue (N = 3, 7%), fever (N = 2, 5%), and infection (N = 2, 5%). At a median follow up time for alive pts of 60.2 months (range: 36.1-82.5 months), the overall response rate (≥ partial response) and clinical benefit response rate (≥ minor response) was 22 and 32%, respectively, with 4 very good partial responses (10%), 5 partial responses (12%), and 4 minor responses (10%). The median PFS was 3.1 months (95% confidence interval [CI]: 2.1-5.1 months), median TTP 2.7 months (95% CI: 2.1-7.5 months), and median OS 18.6 months (95% CI: 12.9-33.0 months). Achieving at least minor response and reaching TTP > 6 months was associated with approximately 35% lower median plasma levels of the enzyme that inactivates aza, plasma cytidine deaminase (CDA, P< .0001). Two of the len refractory pts achieved longer disease control than with any prior regimen and 1 responded immediately after progression on len, bortezomib, and prednisone. Analyses of the methylation state of over 480,000 CpG sites in purified myeloma cells at screening were possible in 11 pts and on day 28 in 8 of them. As in other studies, the majority of differentially methylated CpGs compared to normal plasma cells were hypomethylated in myeloma. Treatment decreased the number of CpGs that were differentially methylated in normal plasma cells by > 0.5% in 6 and by > 5% in 3 of the 8 pts, most pronounced in 2 pts with clinically convincing aza contribution who achieved a reduction in overall differentially methylated CpGs by 23 and 68%, respectively, associated with increased expression of immunoglobulin genes. The study demonstrated tolerability of twice a week SC aza at 50 mg/m² with len and dex in RRMM and suggested aza may help overcome the len/pom refractory state, possibly by activating differentiation pathways. Relatively low response rates and association of clinical benefit with low plasma levels of the aza inactivating enzyme CDA suggest the aza regimen will need to be optimized further and pt selection may be required to maximize benefit.

Daratumumab monotherapy for relapsed/refractory multiple myeloma, focussed on clinical trial-unfit patients and subsequent therapy

Real-world outcomes of daratumumab monotherapy (DM) for relapsed/refractory multiple myeloma (RRMM) have remained unclear. We conducted a multicentre retrospective study of 107 patients receiving DM for RRMM. The cohort included 64 trial-unfit patients whose characteristics could not meet inclusion criteria in two previous clinical trials (GEN501 and SIRIUS). The overall response rate (ORR), and median first and second progression-free survival (PFS1 and PFS2) and overall survival were 42·1%, and 3·6, 8·1 and 11·9 months, respectively. Refractoriness to carfilzomib and/or lenalidomide, and neutropenia (<1.0 × 10⁹ /l) resulted in poorer ORRs. An Eastern Cooperative Oncology Group Performance Status of ≥3, neutropenia (<1.0 × 10⁹ /l), thrombocytopenia (<75 × 10⁹ /l), and renal failure (glomerular filtration rate of <20 ml/min/1·73 m² ) were associated with poor PFS1 and PFS2 in respective univariate analysis. The modified trial-unfit group, based on the above factors, showed significantly negative impacts on PFS1 and PFS2 (hazard ratio 2·823 and 3·677, all P < 0·001) in multivariate analysis despite having a 34% ORR. Fatal infections occurred more often in the modified trial-unfit group than in the others (16·1% vs. 4·3%; P = 0·099). Despite failure of DM, subsequent therapy with pomalidomide-based therapy or carfilzomib-dexamethasone provided a 66·6% ORR. Real-world DM showed favourable efficacies for RRMM and, potentially, additional benefits with subsequent therapies. However, characteristics corresponding with trial-unfitness might offset the efficacy of DM.

Sequencing multiple myeloma therapies with and after antibody therapies

In multiple myeloma (MM), treatment selection and sequencing become increasingly complex with the increasing number of therapeutic options, including antibodies. Choice of treatment is dependent on various factors including patient- and tumor-related features. In addition, treatment-related factors, such as type and response to prior therapy, are also critical in terms of the selection of a new treatment regimen. Furthermore, approval status and reimbursement policies influence treatment choice. At the time of first relapse, patients who received a bortezomib-based regimen can switch to lenalidomide-based treatment, whereas patients who received lenalidomide until progression can switch to a proteasome inhibitor-based therapy. Alternatively, there is increasing evidence that pomalidomide-based triplets are also effective following the development of lenalidomide-refractory disease both in early and later relapse settings. Patients who become refractory to immunomodulatory drugs, proteasome inhibitors, and CD38 antibodies have a poor prognosis. These triple-class refractory patients may benefit from novel, recently approved agents such as XPO1 inhibitors or from participation in a clinical trial. Furthermore, retreatment with agents that were received in previous lines of therapy can also be considered in heavily pretreated patients, for example, in combination with classic cytotoxic drugs. Importantly, with the increasing use of CD38 antibodies in newly diagnosed and early relapsed/refractory MM, more information is needed on the potential value of retreatment with CD38 antibodies. With the introduction of new immunotherapies with novel modes of action, we also need a better understanding of sequencing of immunotherapeutic agents by taking into account the effect of prior therapy on immune function.

Antibody therapies for multiple myeloma

Introduction: Multiple myeloma (MM) is characterized by the uncontrollable proliferation of plasma cells and the excessive production of a specific type of immunoglobulin. Immune system is deregulated in MM and, thus, immunotherapy is a promising therapeutic strategy.Areas covered: The first approach is to use monoclonal antibodies that recognize specific antigens on the surface of myeloma cells, such as CD38 and B-cell maturation antigen. Upon binding to their target, monoclonal antibodies activate the immune cells to destroy the malignant cell. Anti-CD38 molecules as part of highly effective combination regimens have been approved in both newly diagnosed and relapsed/refractory patients and have significantly changed the myeloma treatment landscape in the recent years. Another strategy is to use antibodies that bind both to a molecule on the surface of the myeloma cell and another molecule on the surface of a T-cell (bispecific antibodies). Consecutively, the T-cell comes close to and recognizes the myeloma cell. These have shown promising results in heavily pre-treated patients.Expert opinion: Antibody therapy has significantly enhanced the armamentarium against MM. Further research should focus on tailoring the combination regimens based on disease and patient characteristics in order to optimize the efficacy and safety.

CD38 Expression by Myeloma Cells and Its Role in the Context of Bone Marrow Microenvironment: Modulation by Therapeutic Agents

In the last decades CD38 has emerged as an attractive target for multiple myeloma (MM). CD38 is a novel multifunctional glycoprotein that acts as a receptor, adhesion molecule interacting with CD31 and as an ectoenzyme. As an ectoenzyme, CD38 functions as a metabolic sensor catalyzing the extracellular conversion of NAD+ to the immunosuppressive factor adenosine (ADO). Other ectoenzymes, CD73 and CD203a, together with CD38, are also involved in the alternative axis of extracellular production of ADO, bypassing the canonical pathway mediated by CD39. CD38 is ubiquitously expressed in the bone marrow microenvironment; however, only MM cells display a very high surface density, which lead to the development of several anti-CD38 monoclonal antibodies (mAbs). The efficacy of anti-CD38 mAbs depends from the presence of CD38 on the surface of MM and immune-microenvironment cells. Interestingly, it has been reported that several drugs like lenalidomide, panobinostat, the all-trans retinoic acid and the DNA methyltransferase inhibitors may increase the expression of CD38. Hence, the possibility to modulate CD38 by increasing its expression on MM cells is the pre-requisite to potentiate the clinical efficacy of the anti-CD38 mAbs and to design clinical trials with the combination of anti-CD38 mAbs and these drugs.

Efficacy of daratumumab monotherapy in real-world heavily pretreated patients with relapsed or refractory multiple myeloma

PURPOSE

Daratumumab is a promising new agent for relapsed/refractory multiple myeloma (RRMM). However, there are limited data on its clinical activity and tolerability in the real-world patients. The purpose of this study is to determine the efficacy and toxicity profile of daratumumab monotherapy in the real-life setting.

PATIENTS AND METHODS

Thirty RRMM patients treated with daratumumab who had previously received at least three treatment lines including a proteasome inhibitor and an immunomodulatory drug or had been double refractory (DRMM) were included to the Polish Myeloma Group observational study.

RESULTS

The objective response rate to daratumumab was 42.8%. Median progression-free survival (PFS) and overall survival reached 9.5 and 13.8 months, respectively. Importantly, patients with DR-MM had a significantly shorter PFS than other patients (median PFS of 4.1 vs. 12.1 months). Daratumumab was generally well tolerated, however two patients had their therapy interrupted due to adverse events.

CONCLUSION

Daratumumab monotherapy has significant activity and good tolerance in heavily pretreated RRMM patients.

Contemporary patient-tailored treatment strategies against high risk and relapsed or refractory multiple myeloma

Recurrence of disease due to chemotherapy drug resistance remains a major obstacle to a more successful survival outcome of multiple myeloma (MM). Overcoming drug resistance and salvaging patients with relapsed and/or refractory (R/R) MM is an urgent and unmet medical need. Several new personalized treatment strategies have been developed against molecular targets to overcome this drug resistance. There are several targeted therapeutics with anti-MM activity in clinical pipeline, including inhibitors of anti-apoptotic proteins, monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, fusion proteins, and various cell therapy platforms. For example, B-cell maturation antigen (BCMA)-specific CAR-T cell platforms showed promising activity in heavily pretreated R/R MM patients. Therefore, there is renewed hope for high-risk as well as R/R MM patients in the era of personalized medicine.