Blood Transfusion Management for Patients Treated With Anti-CD38 Monoclonal Antibodies

Antigen masking indirect antiglobulin test can mitigate the interference of Mezagitamab, a novel anti-CD38 antibody, in serological pre-transfusion testing

OBJECTIVES

Investigation of the interference of mezagitamab in serological pre-transfusion testing and the use of DaraEx to overcome it.

BACKGROUND

Administration of anti-CD38 antibodies is a state-of-the-art therapy for patients diagnosed with multiple myeloma. However, treatment with the currently approved anti-CD38 antibodies regularly results in widespread agglutination of red blood cells in serological pre-transfusion testing, making the determination of irregular antibodies and timely transfusion of compatible blood a challenge. Mezagitamab, a novel monoclonal anti-CD38 antibody, is currently under clinical investigation, not only for the treatment of multiple myeloma but also for other indications such as generalised myasthenia gravis.

METHODS/MATERIALS

Mezagitamab or daratumumab spiked plasmas, with or without irregular antibodies, were tested in column agglutination technique cards. DaraEx was used to mitigate occurring interferences.

RESULTS

Mezagitamab interferes with the indirect antiglobulin test, with comparable titers but weaker reaction strengths than daratumumab. DaraEx, a reagent containing Fab fragments of an anti-CD38 antibody, is able to completely overcome this interference in the antigen masking indirect antiglobulin test (AMIAT). DaraEx treatment does not interfere with tested irregular antibodies.

CONCLUSION

All novel anti-CD38 antibodies, such as mezagitamab, have the potential to interfere in serological pre-transfusion testing. While masking only one epitope, DaraEx has so far been an effective mitigation for all clinical anti-CD38 antibodies.

Is drug interference still an issue for pretransfusion testing of patients on anti CD38 and other monoclonal antibody therapies?

Certain therapies that target CD markers on some blood cells can affect pretransfusion testing. Key examples are anti-CD38, CD47 monoclonal antibody (mAb) therapies such as daratumumab (DARA) and magrolimab, which have presented a challenge for transfusion medicine laboratories around the globe. Scientists have been faced with not only introducing a protocol to provide safe blood to patients but also investigating the most effective method to remove the pretransfusion pan-agglutinating interference caused. A number of papers in the last 5 years have reported on various methods to remove pretransfusion interference; however, most of these studies have been conducted only in a few countries. Most recent reviews on this topic have focused on techniques and reagents to remove pretransfusion interference, and dithiothreitol is currently the gold standard for removing DARA interference. However, it was clear from this review that while many laboratories have developed processes for addressing interference in pretransfusion testing, and DARA interference may not be a major issue, there are still laboratories around the world, that may not have adequately addressed this issue. In addition, the impact of mAb interference on widely used techniques such as flow cytometry is unclear.

Naked antibodies and antibody-drug conjugates: targeted therapy for childhood acute lymphoblastic leukemia

The treatment of childhood acute lymphoblastic leukemia (ALL) has reached overall survival rates exceeding 90%. The present and future challenges are to cure the remainder of patients still dying from disease, and to reduce morbidity and mortality in those who can be cured with standard-of-care chemotherapy by replacing toxic chemotherapy elements while retaining cure rates. With the novel therapeutic options introduced in the last years, including immunotherapies and targeted antibodies, the treatment of ALL is undergoing major changes. For B-cell precursor ALL, blinatumomab, an anti-CD19 bispecific antibody, has established its role in the consolidation treatment for both high- and standard-risk first relapse of ALL, in the presence of bone marrow involvement, and may also have an impact on the outcome of high-risk subsets such as infant ALL and Philadelphia chromosome-positive ALL. Inotuzumab ozogamicin, an anti-CD22 drug conjugated antibody, has demonstrated high efficacy in inducing complete remission in relapsed ALL, even in the presence of high tumor burden, but randomized phase III trials are still ongoing. For T-ALL the role of CD38-directed treatment, such as daratumumab, is gaining interest, but randomized data are needed to assess its specific benefit. These antibodies are currently being tested in patients with newly diagnosed ALL and may lead to major changes in the present paradigm of treatment of pediatric ALL. Unlike the past, lessons may be learned from innovations in adult ALL, in which more drastic changes are piloted that may need to be translated to pediatrics.

Risk of new alloimmunization in patients on anti-CD38 treatment using tube LISS-IAT method

BACKGROUND

Daratumumab is a monoclonal antibody that targets CD38, a transmembrane protein expressed on many cells including RBCs and to a greater extent on myeloma cells. It has been used for treatment of multiple myeloma and autoimmune diseases. Transfusion management of patients on such therapy can be challenging as these drugs cross-react with RBC surface antigens and cause panreactivity.

MATERIAL AND METHODS

A retrospective study of the 68 patients treated with anti-CD38 from 2018-2023 was carried out. Data regarding transfusion history and antibody screens were analyzed. Depending whether they had immunohematological work-up before or during the treatment- DAT, antibody screen (CAT and tube), RBC pheno/genotyping and serologic cross-matches (CAT and tube) were performed for each patient. All cases with positive CAT IAT were retested in LISS-tube and cross-matches were performed with phenotypically matched units in LISS-tube.

RESULTS

Antibody screen has shown panagglutination with all panel cells with low and variable agglutination intensity (weak to 2 +). Panagglutination remained positive for 1 - 6 months after drug cessation. Positive DAT was seen in 60,6% patients, while autocontrol was negative. Ficin treated panel-cells eliminated nonspecific reactivity. LISS-tube antibody screen and cross-matches were negative for all patients, apart from 3 patients who had preexisting antibodies. No new antibodies were detected during the course of the study.

CONCLUSION

Among study group there were no newly identified alloantibodies, meaning that the policy of transfusing them with matched RBCs and performing IAT/cross-matches in tube is a safe and effective policy according to the findings of this study.

New Biological Therapies for Multiple Myeloma

Multiple myeloma is a cancer of bone marrow plasma cells that represents approximately 10% of hematologic malignancies. Though it is typically incurable, a remarkable suite of new therapies developed over the last 25 years has enabled durable disease control in most patients. This article briefly introduces the clinical features of multiple myeloma and aspects of multiple myeloma biology that modern therapies exploit. Key current and emerging treatment modalities are then reviewed, including cereblon-modulating agents, proteasome inhibitors, monoclonal antibodies, other molecularly targeted therapies (selinexor, venetoclax), chimeric antigen receptor T cells, T cell-engaging bispecific antibodies, and antibody-drug conjugates. For each modality, mechanism of action and clinical considerations are discussed. These therapies are combined and sequenced in modern treatment pathways, discussed at the conclusion of the article, which have led to substantial improvements in outcomes for multiple myeloma patients in recent years.

Long-term storage protocol of reagent red blood cells treated with 0.01M dithiothreitol (DTT) for pre-transfusion testing of patients receiving anti-CD38 therapy, daratumumab

OBJECTIVE

Use red blood cell stabilizer to store the antibody screening and antibody identification reagent red blood cells (RBCs) treated with 0.01 mol/L DTT and investigate its value in the pre-transfusion examinations of patients treated with daratumumab.

METHOD

Determined the optimal incubation time for the 0.01 mol/L DTT-treated RBCs method by evaluating the effect of treatment at different time points. Added ID-CellStab to store DTT-treated RBCs, determined the maximum shelf life of reagent RBCs by monitoring the hemolysis index, and assessed changes in the antigenicity of blood group antigens on the surface of RBCs during storage with antibody reagents.

RESULT

A protocol for long-term storage of reagent red blood cells treated with the 0.01 mol/L DTT method was established. The optimal incubation time was 40-50 min. RBCs could be stored stably for 18 days after adding ID-CellStab. The protocol was able to eliminate pan-agglutination caused by daratumumab, with no significant changes in the antigens of most blood group systems, except for some attenuation of K antigen and Duffy blood group system antigens during the storage period.

CONCLUSION

The storage protocol of reagent RBCs based on the 0.01 mol/L DTT method does not affect the detection of most blood group antibodies and retains a certain degree of detection ability for anti-K antibodies, allowing patients treated with daratumumab to quickly perform pre-transfusion examinations, making up for the shortcomings of currently commercial reagent RBCs.

Mitigation of therapeutic anti-CD38 antibody interference with fab fragments: How well does it perform?

BACKGROUND

Administration of anti-CD38 antibodies is a state-of-the-art therapy for patients diagnosed with multiple myeloma (MM). However, this treatment frequently leads to pan-agglutination of red blood cells (RBCs) in patients' serological testing making accurate blood typing and timely transfusion of compatible blood a challenging effort. The antigen masking indirect antiglobulin test (AMIAT) is an approach to address this diagnostic challenge.

STUDY DESIGN AND METHODS

A new reagent, called DaraEx plus, uses anti-CD38 Fab fragments to mitigate the anti-CD38 antibody interference in serological assays by masking CD38 on the cell surface. Its performance is extensively examined with commercial sera as well as with patient samples, and compared to the current standard method using dithiothreitol (DTT), which denatures the CD38 antigens on test panel erythrocytes.

RESULTS

In the Bio-Rad ID System, DaraEx plus effectively mitigated the interference caused by anti-CD38 antibodies in 86% of patient samples tested while DTT was successful in only 68%. Moreover, there was no negative influence on DTT-sensitive blood group systems such as KEL upon DaraEx plus treatment. The agglutination reactions of all tested anti-CD38 antibodies (Daratumumab, Felzartamab, and Isatuximab) were inhibited by DaraEx plus. The treatment was successful only if DaraEx plus was added to the test cells before the sample. Some of the other gel card systems tested showed background reactions with DaraEx plus-treated cells.

CONCLUSION

DaraEx plus treatment is straightforward and quick to perform. In the Bio-Rad ID System, it is superior to DTT treatment in the prevention of anti-CD38 antibody interference.

FTL004, an anti-CD38 mAb with negligible RBC binding and enhanced pro-apoptotic activity, is a novel candidate for treatments of multiple myeloma and non-Hodgkin lymphoma

Anti-CD38 monoclonal antibodies (mAbs), daratumumab, and isatuximab have represented a breakthrough in the treatment of multiple myeloma (MM). Recently, CD38-based mAbs were expected to achieve increasing potential beyond MM, which encouraged us to develop new anti-CD38 mAbs to meet clinical needs. In this study, we developed a novel humanized anti-CD38 antibody, FTL004, which exhibited enhanced pro-apoptotic ability and negligible binding to red blood cells (RBCs). FTL004 presented a better ability to induce direct apoptosis independent of Fc-mediated cross-linking against lymphoma and MM cell lines as well as primary myeloma cells derived from MM patients. For instance, FTL004 induced RPMI 8226 cells with 55% early apoptosis cells compared with 20% in the isatuximab-treated group. Of interest, FTL004 showed ignorable binding to CD38 on human RBCs in contrast to tumor cells, even at concentrations up to 30 μg/mL. Furthermore, with an engineered Fc domain, FTL004 displayed stronger antibody-dependent cellular cytotoxicity (ADCC) against CD38+ malignant cells. In vivo MM and non-Hodgkin lymphoma tumor xenograft models showed that FTL004 possessed an effective anti-tumor effect. Cryo-electron microscopy structure resolved two epitope centers of FTL004 on CD38: one of which was unique while the other partly overlapped with that of isatuximab. Taken together, FTL004 distinguishes it from other CD38 targeting mAbs and represents a potential candidate for the treatment of MM and non-Hodgkin lymphoma.

Development of Mia Phenotyping Using Paper-Based Device

The MNS7 (Mi^a) blood group antigen is found at a different prevalence among different ethnic groups. Anti-Mi^a can cause hemolytic disease of the fetus and newborn (HDFN) and both acute- and delayed-type hemolytic transfusion reactions (HTR). Mi^a typing should be performed in donors to prevent life-threatening hemolytic transfusion reactions. The gel card and standard tube methods still need specialized equipment, centrifugation, and expertise for result interpretation. We used a novel paper-based analytical device (PAD) pre-coated with monoclonal IgM anti-Mi^a for Mi^a phenotyping. We measured grey pixel intensity in blood typing results for interpretation processing using OpenCV at the sample (SP) and elution parts (EP); furthermore, we used the SP: EP ratio and F-score as analysis criteria. We typed 214 blood EDTA samples with PAD-Mi^a and then compared with gel card results for setting an analysis criterion. We observed 100% sensitivity, specificity, and accuracy when we applied the SP: EP ratio and F-score with the optimal criterion (1.07 and 0.17 for SP: EP ratio and F-score, respectively). The validation of PAD-Mi^a typing for blood donor samples (n = 150) via F-score gave 100% sensitivity and specificity when compared with the gel card method; therefore, we argue that PAD-Mi^a typing can be used for Mi^a phenotyping without sero-centrifugation. Moreover, to study the correlation between genotype and phenotype, PCR-SSP was performed to identify GYP(B-A-B) hybrids. The results revealed that all Mi^a+ blood samples gave a positive with GP. Hut, GP. HF, GP. Mur, GP. Hop, and GP. Bun. Results of the gel card method and PCR-SSP were concordant. Hence, using PAD-Mi^a typing in blood donors would be helpful for creating a phenotype database of blood donors for reducing alloimmunization risks.

Anti-CD38 monoclonal antibody interference with blood compatibility testing: Differentiating isatuximab and daratumumab via functional epitope mapping

BACKGROUND

There are two FDA-approved anti-CD38 monoclonal antibodies for treatment of multiple myeloma: isatuximab and daratumumab. Owing to expression of CD38 on reagent red blood cells (RBCs), these antibodies interfere with indirect antiglobulin tests (IATs). We sought to understand differences in such interference by performing binding experiments.

STUDY DESIGN AND METHODS

In vitro experiments to compare the binding to RBCs of isatuximab and daratumumab alone or in the presence of a mouse anti-human CD38 antibody (HB-7 or AT13/5) or a nicotinamide adenine dinucleotide-analog CD38 inhibitor were performed and quantified by flow cytometry, imaging, mass spectrometry, surface plasmon resonance, and LigandTracer technologies. Serologic testing was performed on plasma samples spiked with isatuximab or daratumumab.

RESULTS

CD38 expressed on RBCs can be directly bound by daratumumab, whereas isatuximab requires a co-factor, such as HB-7, AT13/5, or a CD38 inhibitor, suggesting that the isatuximab epitope on RBCs is masked in vitro. Daratumumab samples more frequently showed interference and had stronger reactions than isatuximab samples. Dithiothreitol treatment was equally effective in mitigating the interference caused by either drug.

DISCUSSION

Both isatuximab and daratumumab interfere with IATs but at different magnitudes, reflecting distinct binding to CD38 on RBCs. From the binding studies, we conclude that the isatuximab epitope on RBCs is masked in vitro and binding requires a certain CD38 conformation or co-factor. This circumstance may explain why interference is seen only in a subset of patients receiving isatuximab when compared with interference seen in most patients on daratumumab therapy.

Anti-CD38 antibody therapy for patients with relapsed/refractory multiple myeloma: differential mechanisms of action and recent clinical trial outcomes

CD38 is a transmembrane glycoprotein that functions both as a receptor and an ectoenzyme, playing key roles in the regulation of calcium signaling and migration of immune cells to tumor microenvironments. High expression on multiple myeloma (MM) cells and limited expression on normal cells makes CD38 an ideal target for the treatment of MM patients. Two monoclonal antibodies directed at CD38, isatuximab and daratumumab, are available for use in patients with relapsed and/or refractory MM (RRMM); daratumumab is also approved in newly diagnosed MM and light-chain amyloidosis. Clinical experience has shown that anti-CD38 antibody therapy is transforming treatment of MM owing to its anti-myeloma efficacy and manageable safety profile. Isatuximab and daratumumab possess similarities and differences in their mechanisms of action, likely imparted by their binding to distinct, non-overlapping epitopes on the CD38 molecule. In this review, we present the mechanistic properties of these two antibodies and outline available evidence on their abilities to induce adaptive immune responses and modulate the bone marrow niche in MM. Further, we discuss differences in regulatory labeling between these two agents and analyze recent key clinical trial results, including evidence in patients with underlying renal impairment and other poor prognostic factors. Finally, we describe the limited existing evidence for the use of isatuximab or daratumumab after disease progression on prior anti-CD38 mono- or combination therapy, highlighting the need for additional clinical evaluations to define optimal anti-CD38 antibody therapy selection and sequencing in RRMM.

Effect of clinical application of anti-CD38 and anti-CD47 monoclonal antibodies on blood group detection and transfusion therapy and treatment

BACKGROUND

To investigate the effect of anti-CD38 monoclonal antibodies (mAb) (daratumumab, DARA) and anti-CD47 mAb combined with azacytidine on blood transfusion compatibility tests, transfusion effects in the treatment of multiple myeloma or acute myeloid leukemia and the corresponding management strategy.

MATERIALS AND METHODS

Among the 19 patients who were treated with DARA and anti-CD47 mAb, 4 patients with cross matching incompatibility were selected. The ABO blood group, the Rh blood group, irregular antibody screening and direct antiglobulin test (DAT) and cross matching testing were performed before and after the application of mAbs using serological methods. Then, irregular antibody screening and microcolumn gel cross matching tests were performed with donor and recipient erythrocytes and serum treated with DL-dithiothreitol (DTT) and Immucor kit, respectively. The transfusion effect was monitored.

RESULTS

21.05% (4/19) patients had mismatched cross-matching results after mAb treatment. The agglutination intensity of irregular antibody screening tests (3 + ∼ 4 +) after anti-CD47 mAb was higher than that (1 + ∼ 2 +) after DARA. In the DARA group, treating RBCs with 0.2 mol L^-1 DTT eliminated the DARA interference with antibody screening. In the anti-CD47 mAb group, the antibody screening, cross-matching test and DAT had been strongly interfered, and using Immucor kit eliminated the interference with antibody screening testing. There was no difference in the transfusion effect.

CONCLUSION

The application of mAb drugs led to incompatibility of cross matching tests, and the transfusion effect was not affected.

Roadmap for new practitioners to navigate the multiple myeloma landscape

Multiple myeloma (MM) is a blood cancer in which monoclonal plasma cells cause end organ damage resulting in hypercalcemia, renal failure, anemia, and bone lesions. MM is considered incurable, however, recent advances in treatment have improved survival. Historically, MM has been treated with immunomodulatory drugs (IMiDs), proteosome inhibitors (PIs), and corticosteroids. While newer therapeutic approaches such as monoclonal antibodies and cellular therapies have broadened the treatment horizon, the selection and sequencing of these therapies has become more complex. This review aims to help advanced practice providers navigate through the diagnosis, staging, treatment, and supportive care considerations in the MM space.

Panagglutination on the indirect antiglobulin test... this is the challenge!

Panagglutination on the indirect antiglobulin test is one of the most challenging dilemmas of pretransfusion testing. It occurs when patient sera react with all red blood cells tested, that is, with both screening and identification panel cells. Two main questions must be answered. The first is to determine whether panagglutination results from the presence of autoantibody and/or alloantibody (single alloantibody or multiple alloantibodies or antibody to high-incidence antigen). The second problem is to detect the possible concomitant presence of clinically significant alloantibodies masked by panagglutination. The purpose of this mini-review is to describe the situations that can cause panagglutination and to develop algorithms which can resolve the problem. The two main points in the evaluation of panagglutination involve the assessment of the intensity of reactivity with the reagent red cells used and whether the autocontrol is positive or not. It is imperative to understand the laboratory results and the techniques available that guide the investigative process.

CD38 a biomarker and therapeutic target in non-hematopoietic tumors

The type II transmembrane glycoprotein CD38 has recently been implicated in regulating metabolism and the pathogenesis of multiple conditions, including aging, inflammation and cancer. CD38 is overexpressed in several tumor cells and microenvironment tumoral cells, associated to migration, angiogenesis, cell invasion and progression of the disease. Thus, CD38 has been used as a progression marker for different cancer types as well as in immunotherapy. This review focuses on describing the involvement of CD38 in various non-hematopoietic cancers.

Cancer Immunotherapies: What the Perioperative Physician Needs to Know

Purpose of Review

For patients with cancer, treatment may include combination therapy, including surgery and immunotherapy. Here, we review perioperative considerations for the patient prescribed immunotherapeutic agents.

Recent Findings

The perioperative period is a poignant moment in the journey of a patient with cancer, potentially deemed most influential compared to other moments in the care continuum. Several immunotherapeutic medications have been employed near the time of surgery to potentially increase effectiveness. Of the various drug classes, including immune checkpoint inhibitors, cytokines, toll-like receptor agonists, and oncolytic viruses, among others, several notable immune-related adverse effects were noted. They range from minor effects to more serious ones, such as renal failure, myocarditis, and tumor growth.

Summary

Surgery and immunotherapy are often employed in combination for primary treatment and prevention of cancer recurrence. Careful review and consideration of the pharmacokinetics, pharmacodynamics, and toxicities of immunotherapy benefit the perioperative physician and their patients.

Targeting plasma cells with daratumumab aids in the treatment of post-transplant autoimmune-like hepatitis

Antibody-mediated autoimmune-like hepatitis is a rare and challenging occurrence after hematopoietic cell transplant (HCT). We present the case of a 16-year-old male patient with Ph+ ALL who underwent matched sibling donor HCT and developed autoimmune-like hepatitis after receiving ponatinib for post-HCT maintenance, evidenced by marked plasma cell infiltrate on liver biopsy. He was successfully treated with steroids and daratumumab, an anti-CD38-monoclonal antibody. The dramatic response in this patient warrants expanded investigation of daratumumab for plasma cell-mediated disorders post-HCT. It further highlights that identifying mechanisms of immune-mediated injury can allow for directed therapy and limit exposure to broad immune suppression.

Antibody incidence and red blood cell transfusions in patients on daratumumab

BACKGROUND

Daratumumab (Dara), an anti-CD38 monoclonal antibody for hematologic malignancies, interferes with routine blood bank testing, specifically affecting the antibody screen and identification panels. In 2016, the AABB recommended performing a baseline phenotype or genotype before a patient (Pt) begins taking anti-CD38 to avoid this interference and potential problems with transfusion. The objective of this study was to assess red blood cell (RBC) utilization and subsequent incidence of alloimmunization to the transfused RBCs in patients receiving Dara.

METHODS AND MATERIALS

We monitored 244 patients taking Dara to determine their red blood cell transfusions and incidence of clinically significant antibody formation before and following administration of Dara. Poisson generalized estimating equations with log link were used comparing the post-Dara incidence and prevalence to those prior, with significance defined as p < .05.

RESULTS

From September 1, 2015 to December 22, 2018, 244 patients on Dara were identified, of which 145 patients (59.4%) received a red blood cell transfusion. Antibody screens were performed on 97 of the 145 patients at least 2 weeks following RBC transfusion. Four of the total transfused patients (2.8% total, 4.1% patients with follow-up antibody screen testing) formed new clinically significant alloantibodies, which was not significantly different from Asare's hematologic incidence (p = .98/p = .49).

CONCLUSIONS

This study showed our patients on Dara did not form alloantibodies following RBC transfusion at a higher incidence than similar patient populations.

Generation of 'designer erythroblasts' lacking one or more blood group systems from CRISPR/Cas9 gene-edited human-induced pluripotent stem cells

Despite the recent advancements in transfusion medicine, red blood cell (RBC) alloimmunization remains a challenge for multiparous women and chronically transfused patients. At times, diagnostic laboratories depend on difficult-to-procure rare reagent RBCs for the identification of different alloantibodies in such subjects. We have addressed this issue by developing erythroblasts with custom phenotypes (Rh null, GPB null and Kx null/Kell low) using CRISPR/Cas9 gene-editing of a human induced pluripotent stem cell (hiPSC) parent line (OT1-1) for the blood group system genes: RHAG, GYPB and XK. Guide RNAs were cloned into Cas9-puromycin expression vector and transfected into OT1-1. Genotyping was performed to select puromycin-resistant hiPSC KOs. CRISPR/Cas9 gene-editing resulted in the successful generation of three KO lines, RHAG KO, GYPB KO and XK KO. The OT1-1 cell line, as well as the three KO hiPSC lines, were differentiated into CD34+ CD41+ CD235ab+ hematopoietic progenitor cells (HPCs) and subsequently to erythroblasts. Native OT1-1 erythroblasts were positive for the expression of Rh, MNS, Kell and H blood group systems. Differentiation of RHAG KO, GYPB KO and XK KO resulted in the formation of Rh null, GPB null and Kx null/Kell low erythroblasts, respectively. OT1-1 as well as the three KO erythroblasts remained positive for RBC markers-CD71 and BAND3. Erythroblasts were mostly at the polychromatic/ orthochromatic stage of differentiation. Up to ~400-fold increase in erythroblasts derived from HPCs was observed. The availability of custom erythroblasts generated from CRISPR/Cas9 gene-edited hiPSC should be a useful addition to the tools currently used for the detection of clinically important red cell alloantibodies.

Keeping Myeloma in Check: The Past, Present and Future of Immunotherapy in Multiple Myeloma

Multiple myeloma is an incurable disease of malignant plasma cells and an ideal target for modern immune therapy. The unique plasma cell biology maintained in multiple myeloma, coupled with its hematological nature and unique bone marrow microenvironment, provide an opportunity to design specifically targeted immunotherapies that selectively kill transformed cells with limited on-target off-tumor effects. Broadly defined, immune therapy is the utilization of the immune system and immune agents to treat a disease. In the context of multiple myeloma, immune therapy can be subdivided into four main categories: immune modulatory imide drugs, targeted antibodies, adoptive cell transfer therapies, and vaccines. In recent years, advances in all four of these categories have led to improved therapies with enhanced antitumor activity and specificity. In IMiDs, modified chemical structures have been developed that improve drug potency while reducing dose limiting side effects. Targeted antibody therapies have resulted from the development of new selectively expressed targets as well as the development of antibody drug conjugates and bispecific antibodies. Adoptive cell therapies, particularly CAR-T therapies, have been enhanced through improvements in the manufacturing process, as well as through the development of CAR constructs that enhance CAR-T activation and provide protection from a suppressive immune microenvironment. This review will first cover in-class breakthrough therapies for each of these categories, as well as therapies currently utilized in the clinic. Additionally, this review will explore up and coming therapeutics in the preclinical and clinical trial stage.

Use of an in-house trypsin-based method to resolve the interference of daratumumab

BACKGROUND

Daratumumab (DARA) is a monoclonal antibody for treatment of plasma cell myeloma targeting CD38, a surface molecule expressed on plasma cells and red blood cells (RBCs). This complicates blood bank testing, requiring dithiothreitol (DTT) to remove DARA interference. A simple in-house method of removing DARA interference without use of DTT, a potentially hazardous chemical, is desirable. We demonstrate a trypsin-based method to remove interference in antibody testing at a medical center (MC), with parallel testing at an immunohematology reference laboratory (IRL).

STUDY DESIGN AND METHODS

Pre-DARA type and screen (T&S) samples were obtained from 61 patients for antibody testing and RBC phenotyping using untreated reagent RBCs. Subsequent post-DARA T&S testing was performed with untreated reagent RBCs to demonstrate interference and repeated after trypsin treatment. Positive trypsin-treated antibody screens were reflexed to antibody identification using trypsin-treated panel cells. Parallel testing was performed on the same post-DARA samples at IRL.

RESULTS

DARA interference was detected in 61/61 (100%) samples by MC and IRL. After trypsin treatment, DARA interference was eliminated in 60/61 (98.4%) antibody screens by both institutions with an overall percent agreement of 96.7% (95% confidence interval [CI] 88.7%-99.6%). Identification of known alloantibodies was confirmed in 3/3 patients with 100% concordant results between MC and IRL. There were no false-negative results demonstrated by IRL's functionally CD38-negative controls.

CONCLUSION

Our in-house trypsin-based method enables pretransfusion testing of patients receiving DARA in an accurate and cost-effective manner without missing clinically significant alloantibodies. This presents an additional testing option where DTT use is undesirable.

2-Mercaptoethanol (2-ME)-based IATs or Polybrene method mitigates the interference of daratumumab on blood compatibility tests

OBJECTIVES

Treating red blood cells (RBCs) with dithiothreitol (DTT) is a wildly-recommended to overcome the interference of the daratumumab (DARA) with blood compatibility testing. Nevertheless, DTT can be hard to obtain in the clinical laboratory, while its use in routine practice may be time-consuming. In the following study, we explored the feasibility of using a commercial 2-mercaptoethanol (2-ME) working solution or the time-saving Polybrene method to mitigate DARA interference.

METHODS

Antibody screening and cross-matching were performed using 2-ME or DTT-based indirect antiglobulin tests (IATs) and Polybrene method (with human IgG anti-E same IATs titer as DARA as positive control) on 37 samples. Most clinically important blood group antigens on RBCs were detected after treatment with 2-ME or DTT.

RESULTS

Treating RBCs with 2-ME eliminates the DARA interference with the antibody screening or cross-matching; yet, K antigen is denatured during treatment. DARA does not interfere with antibody screening and cross-matching via Polybrene method, while 2+ agglutinations of anti-E antibody with the same titer (IATs method) as DARA could be observed in the positive controls via this method.

CONCLUSION

2-ME-based IATs or Polybrene method could replace DTT-based IATs to mitigate DARA interference.

Overcoming Drug Interference in Transfusion Testing: A Spotlight on Daratumumab

Daratumumab, a monoclonal antibody therapeutic, is highly efficacious and widely used in all stages of multiple myeloma and amyloidosis and has promising activity in other hematologic disorders. Daratumumab interacts with red blood cells, interfering with pre-transfusion testing. This interference can lead to compromising transfusion safety, extensive blood bank work ups and delays in provision of compatible units. Several methods have been developed to negate daratumumab interference with indirect antiglobulin testing. They are based on i) standard blood bank techniques including dithiothreitol and enzymatic treatment of reagent cells, using reagent red blood cells negative for CD38, ii) blocking CD38 antigens on reagent or donor cells, iii) neutralization of anti-CD38 antibody in patient plasma prior to testing, and iv) extended antigen typing of patient red blood cells in conjunction with provision of phenotypically matched units for transfusion. Implementation of those methods by the blood bank should be a planned effort coordinated with the patient’s clinical team. Timely involvement of blood bank and transfusion services and educational efforts by both blood banks and clinical providers can improve the overall daratumumab safety profile in regard to blood transfusion.

Radix Astragali polysaccharide RAP directly protects hematopoietic stem cells from chemotherapy-induced myelosuppression by increasing FOS expression

Radix Astragali polysaccharide RAP has been reported to play a crucial role in hematopoiesis without a clear mechanism. In this study, RAP's effects to enhance the recovery of cyclophosphamide (Cy)-suppressed bone marrow and blood cells is confirmed in vivo first. Confocal micrographs demonstrated the interesting direct binding of FITC-RAP to hematopoietic stem cells (HSC) in bone marrow. RAP protects both mice and human HSC in terms of cell morphology, proliferation, and apoptosis. RNA-sequencing and shRNA approaches revealed FOS to be a key regulator in RAP's protection. These evidences provide an unreported mechanism that RAP directly protects hematopoietic stem cells from chemotherapy-induced myelosuppression by increasing FOS expression.

Optimizing transfusion management of multiple myeloma patients receiving daratumumab-based regimens

BACKGROUND

Daratumumab, a human anti-CD38 monoclonal antibody used to treat multiple myeloma, interferes with pretransfusion testing and can mask alloantibodies. Incidence of alloimmunization in patients on daratumumab has not been well characterized, and optimal transfusion guidelines regarding prophylactic antigen matching, accounting for both patient safety and efficiency, have not been well established for these patients.

METHODS

Records of patients who received daratumumab between January 1, 2014 and July 2, 2019 were reviewed. Daratumumab interference with pretransfusion testing was managed by testing with reagent red blood cells (RBCs) treated with 0.2 M dithiothreitol. When daratumumab was present during antibody testing, patients were transfused with RBC units prophylactically matched for D, C, c, E, e, and K antigens per hospital policy.

RESULTS

Out of 90 patients identified, 52 received a total of 638 RBC transfusions (average of 12.3 units per patient, SD 17.2, range 1-105, median 5 among those transfused). Alloantibodies existing before daratumumab initiation were identified in seven patients. No new alloantibodies were detected in any patients after starting daratumumab treatment.

CONCLUSIONS

The incidence of alloimmunization in patients receiving daratumumab is low. Whether this is due to the effect of daratumumab, underlying pathophysiology, or other factors, is unknown. Because these patients require a large number of RBC transfusions overall and have little observed alloimmunization, phenotype matching (beyond RhD) may be unnecessary. Since the use of dithiothreitol cannot rule out the presence of anti-K, we recommend transfusion of ABO-compatible units, prophylactically matched for the D and K antigens only.

Assessment of Healthcare Professionals' Knowledge and Understanding of the Risk of Blood Typing Interference with Daratumumab: A Survey of 12 European Countries

INTRODUCTION

Daratumumab, a monoclonal antibody targeting CD38, is approved to treat multiple myeloma. Red blood cells express low levels of CD38, which can result in a false-positive antibody screen in daratumumab-treated patients. Educational materials were developed to inform healthcare professionals (HCPs) and blood transfusion management department personnel (BTMDP) about this risk and recommended measures to mitigate that risk. Materials were distributed in European countries where daratumumab was commercially available. This post-authorization safety study was designed to evaluate whether HCPs and BTMDP understood the materials.

METHODS

An anonymous, cross-sectional, non-interventional, web-based survey was distributed in 12 European countries. Four key questions were identified, for which a correct answer from at least 80% of respondents was considered indicative of satisfactory effectiveness.

RESULTS

A total of 408 participants completed the questionnaires (62.3% (n = 254) HCPs and 37.7% (n = 154) BTMDP). Responses were consistent between groups. All respondents were aware of the educational materials (the first key question) and at least 80% correctly answered three of the four key questions. A key question regarding which blood typing test(s) daratumumab interferes with did not achieve satisfactory effectiveness (60% correct responses). In a weighted analysis, 79% of respondents correctly identified the recommended measures for daratumumab-treated patients requiring transfusion. This was attributed to an error in the survey's German translation; in a sensitivity analysis, 90% of participants correctly responded to this question.

CONCLUSIONS

Results suggest that participants were aware of the educational materials, the risk of daratumumab interference with blood testing, and recommended measures to mitigate that risk.

Impact of new myeloma agents on the transfusion laboratory

Monoclonal antibody (mAb) therapy targeting CD38 and CD47 antigens expressed on cancer cells has transformed therapy options for patients with multiple myeloma as well as other haematological and non-haematological malignancies. While the on target effects of these new drugs highlight the promise of precision cancer therapeutics, the unintended, off target binding of drugs to red blood cells (RBCs) and platelets has required transfusion service laboratories (TSL) and immunohaematology reference laboratories (IRL) to innovate and rapidly set up processes and testing protocols to overcome the significant interference in routine pre-transfusion tests caused by these agents. Binding of anti-CD38 and anti-CD47 drugs to reagent RBCs leads to false positive pan-agglutination during the antihuman globulin phase of testing, making it difficult to rule out underlying alloantibodies, and leading to delays in setting up compatible units for RBC transfusion. Anti-CD47 agents can also interfere with ABO/Rh typing studies. Several methods to successfully mitigate interference have been described, such as treatment of reagent RBCs with reducing agents or enzymes, allogeneic RBC adsorption studies and drug specific neutralisation assays; all methods have limitations. TSLs should select an approach that best fits their workflow and expertise and takes into consideration their level of access to specialised outside testing, local blood supplier capabilities, and the type of patient population served. For platelet refractory patients, samples should be tested by platelet antibody assays that are known to be unaffected by drug therapy. RBC transfusion support for multiple myeloma patients receiving anti-CD38 or anti-CD47 drugs can be optimised by establishing good communication between the clinical teams and TSLs, building electronic notification processes, and ensuring timely completion of baseline pre-transfusion testing and RBC phenotype/genotype prior to starting therapy. Staff education, standardisation of laboratory mitigation measures, and implementation of testing algorithms that consider mAb-induced interference when working up a pan-agglutinin help to significantly decrease delays that would otherwise result if standard methods were employed to complete antibody identification studies.

Monoclonal antibodies in relapsed/refractory myeloma: updated evidence from clinical trials, real-life studies, and meta-analyses

Introduction: In the last few years, monoclonal antibodies have rapidly modified the therapeutic strategies for treating patients with multiple myeloma.Areas covered: In this review, the most recent literature data regarding indications for which monoclonal antibodies are currently or will be shortly approved as salvage therapies in relapsed/refractory myeloma are discussed. In particular, updated results until March 22, 2020 of antibodies directed against CD38 (daratumumab and isatuximab), SLAMF7 (elotuzumab), BCMA (GSK2857916/belantamab mafodotin), and PD-1/PD-1 L axis (nivolumab and pembrolizumab) will be analyzed in detail.Expert opinion: Monoclonal antibodies represent a new, very effective approach that will open novel and dynamic treatment scenarios for myeloma patients in the coming years. Optimal positioning and selection of different antibodies that are or will be soon available, appropriate combinations and careful evaluation of possible new toxicities should be considered in the future management of these patients.

Anti-body building: The exercise of advancing immune based myeloma therapies

The last decade has seen a marked improvement in the outcomes of patients with multiple myeloma. Much of this has been due to not only the advent of new therapies, but their inherent ability to be combined into 3 and 4 drug regimens without resulting in unacceptable toxicity. The general gestalt has been to combine agents of varied mechanisms of action. With the primary classes of agents such as proteasome inhibitors and immunomodulatory drugs as bases, the advent of antibody-based therapy in myeloma has allowed us to easily augment these therapies; much in the same way rituximab impacted the lymphoma world. With the approvals of daratumumab, elotuzumab and isatuximab; the myeloma world was ushered into the next wave of targeted agents. Here, we take a look at the current landscape of "off-the-shelf" antibody-based therapies in myeloma and peer into the next wave of multi-functional targeted agents.

Understanding the demand for phenotyped red blood cell units and requests to perform molecular red blood cell typing for Australian patients

BACKGROUND

Australian Red Cross Lifeblood has seen a 50 % increase in demand for phenotyped red blood cell (RBC) units between 2016-2018 and a 30 % increase in demand in 2018 to perform molecular RBC typing on patient samples. Lifeblood conducted a survey to understand transfusion laboratory practices for requesting patient phenotyping and/or molecular RBC typing and for selecting phenotyped RBC units in various patient groups.

STUDY DESIGN AND METHODS

An electronic Qualtrics survey form was sent to 296 transfusion laboratories with questions designed to understand the practice of selecting phenotyped RBC units and reasons for requesting extended serology or molecular RBC typing.

RESULTS

49 (16.6 %) transfusion laboratories provided data. Reasons to request extended phenotyping and/or molecular RBC typing for patients included; chronic transfusion (n = 31 laboratories), sickle cell disease (n = 25), Thalassemia (n = 23), requirement for anti-CD38 or other MAB therapy (n = 23) or Myelodysplasia (n = 22). Forty-seven transfusion laboratories provided responses with reasons for requesting molecular RBC typing which included: predicting phenotype in patients with multiple antibodies (n = 31), prior to administering anti-CD38 or other MAB therapies (n = 29), for pregnancy related transfusions (n = 28) or for confirming the phenotype of recently transfused patients (n = 18).

CONCLUSION

Transfusion laboratory practices indicated that phenotyped RBC units were selected for patients requiring chronic transfusion support and/or undergoing MAB therapy. Requests for molecular RBC typing occurred for more complex patient requirements where serological investigations were not suitable or possible due to reagent restrictions.

New Insights in Autoimmune Hemolytic Anemia: From Pathogenesis to Therapy Stage 1

Autoimmune hemolytic anemia (AIHA) is a highly heterogeneous disease due to increased destruction of autologous erythrocytes by autoantibodies with or without complement involvement. Other pathogenic mechanisms include hyper-activation of cellular immune effectors, cytokine dysregulation, and ineffective marrow compensation. AIHAs may be primary or associated with lymphoproliferative and autoimmune diseases, infections, immunodeficiencies, solid tumors, transplants, and drugs. The direct antiglobulin test is the cornerstone of diagnosis, allowing the distinction into warm forms (wAIHA), cold agglutinin disease (CAD), and other more rare forms. The immunologic mechanisms responsible for erythrocyte destruction in the various AIHAs are different and therefore therapy is quite dissimilar. In wAIHA, steroids represent first line therapy, followed by rituximab and splenectomy. Conventional immunosuppressive drugs (azathioprine, cyclophosphamide, cyclosporine) are now considered the third line. In CAD, steroids are useful only at high/unacceptable doses and splenectomy is uneffective. Rituximab is advised in first line therapy, followed by rituximab plus bendamustine and bortezomib. Several new drugs are under development including B-cell directed therapies (ibrutinib, venetoclax, parsaclisib) and inhibitors of complement (sutimlimab, pegcetacoplan), spleen tyrosine kinases (fostamatinib), or neonatal Fc receptor. Here, a comprehensive review of the main clinical characteristics, diagnosis, and pathogenic mechanisms of AIHA are provided, along with classic and new therapeutic approaches.

The Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of multiple myeloma

Outcomes in multiple myeloma (MM) have improved dramatically in the last two decades with the advent of novel therapies including immunomodulatory agents (IMiDs), proteasome inhibitors and monoclonal antibodies. In recent years, immunotherapy for the treatment of MM has advanced rapidly, with the approval of new targeted agents and monoclonal antibodies directed against myeloma cell-surface antigens, as well as maturing data from late stage trials of chimeric antigen receptor CAR T cells. Therapies that engage the immune system to treat myeloma offer significant clinical benefits with durable responses and manageable toxicity profiles, however, the appropriate use of these immunotherapy agents can present unique challenges for practicing physicians. Therefore, the Society for Immunotherapy of Cancer convened an expert panel, which met to consider the current role of approved and emerging immunotherapy agents in MM and provide guidance to the oncology community by developing consensus recommendations. As immunotherapy evolves as a therapeutic option for the treatment of MM, these guidelines will be updated.

The Changing Landscape of Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) is a greatly heterogeneous disease due to autoantibodies directed against erythrocytes, with or without complement activation. The clinical picture ranges from mild/compensated to life-threatening anemia, depending on the antibody's thermal amplitude, isotype and ability to fix complement, as well as on bone marrow compensation. Since few years ago, steroids, immunesuppressants and splenectomy have been the mainstay of treatment. More recently, several target therapies are increasingly used in the clinical practice or are under development in clinical trials. This has led to the accumulation of refractory/relapsed cases that often represent a clinical challenge. Moreover, the availability of several drugs acting on the different pathophysiologic mechanisms of the disease pinpoints the need to harness therapy. In particular, it is advisable to define the best choice, sequence and/or combination of drugs during the different phases of the disease. In particular relapsed/refractory cases may resemble pre-myelodysplastic or bone marrow failure syndromes, suggesting a careful use of immunosuppressants, and vice versa advising bone marrow immunomodulating/stimulating agents. A peculiar setting is AIHA after autologous and allogeneic hematopoietic stem cell transplantation, which is increasingly reported. These cases are generally severe and refractory to standard therapy, and have high mortality. AIHAs may be primary/idiopathic or secondary to infections, autoimmune diseases, malignancies, particularly lymphoproliferative disorders, and drugs, further complicating their clinical picture and management. Regarding new drugs, the false positivity of the Coombs test (direct antiglobulin test, DAT) following daratumumab adds to the list of difficult diagnosis, together with the passenger lymphocyte syndrome after solid organ transplants. Diagnosis of DAT-negative AIHAs and evaluation of disease-related risk factors for relapse and mortality, notwithstanding improvement in diagnostic approach, are still an unmet need. Finally, AIHA is increasingly described following therapy of solid cancers with inhibitors of immune checkpoint molecules. On the whole, the double-edged sword of new pathogenetic insights and therapies has changed the landscape of AIHA, both providing enthusiastic knowledge and complicating the clinical management of this disease.

Risk of RBC alloimmunization in multiple myeloma patients treated by Daratumumab

BACKGROUND

Daratumumab (DARA) is a human monoclonal antibody for the treatment of multiple myeloma (MM). DARA binds to CD38 on RBCs and interferes with detection of RBC alloantibodies. The objective of this study was to evaluate the risk of RBC alloimmunization in MM patients treated with DARA.

MATERIALS AND METHODS

A retrospective study of the complete serological profile and transfusion history of 45 MM patients received transfusion and treated with DARA from July 2015 to December 2018 was undertaken. All cases with positive Ab screens were treated with DTT to identify RBC alloantibodies. RBC transfusion history was monitored between the first DARA dose to the last or extending to the first negative Ab screen after the last DARA dose if the Ab screen was ever positive. Forty-six MM patients received transfusion but not DARA were studied as control group.

RESULTS

Totally 184 Ab screens were done on 45 patients transfused with ABO-Rh compatible RBCs, phenotypically matched units or both. None of them showed detectable alloantibodies after DTT treatment. The duration of Ab screening positivity varied markedly, ranging from 25 days to 5 months after the last dose. Two of 46 patients in the control group had preexisting alloantibodies but no new alloantibodies were detected during study period.

CONCLUSIONS

Our results indicate that the risk of forming new RBC alloantibodies after transfusion in MM patients treated with current regimens is very low and no DARA-associated difference in the alloimmunization risk. No significant difference in alloimmunization is detected between ABO-Rh compatible and phenotypically matched transfusion.

Review of current transfusion therapy and blood banking practices

Transfusion Medicine is a dynamically evolving field. Recent high-quality research has reshaped the paradigms guiding blood transfusion. As increasing evidence supports the benefit of limiting transfusion, guidelines have been developed and disseminated into clinical practice governing optimal transfusion of red cells, platelets, plasma and cryoprecipitate. Concepts ranging from transfusion thresholds to prophylactic use to maximal storage time are addressed in guidelines. Patient blood management programs have developed to implement principles of patient safety through limiting transfusion in clinical practice. Data from National Hemovigilance Surveys showing dramatic declines in blood utilization over the past decade demonstrate the practical uptake of current principles guiding patient safety. In parallel with decreasing use of traditional blood products, the development of new technologies for blood transfusion such as freeze drying and cold storage has accelerated. Approaches to policy decision making to augment blood safety have also changed. Drivers of these changes include a deeper understanding of emerging threats and adverse events based on hemovigilance, and an increasing healthcare system expectation to align blood safety decision making with approaches used in other healthcare disciplines.

Impact of Novel Monoclonal Antibody Therapeutics on Blood Bank Pretransfusion Testing

Novel monoclonal antibody therapies are increasing in number and clinical significance as their role in oncologic formularies expands. Anti-CD38 and anti-CD47/SIRPα agents commonly interfere with pretransfusion compatibility testing. Anti-CD38 interference is mitigated by dithiothreitol, which disrupts CD38 antigen on reagent red cells; however, this modification limits rule-out of all clinically significant antibodies. Several anti-CD47 agents are in clinical trials and demonstrate wide variability in pretransfusion testing interference. Modifications to pretransfusion testing can limit interference by anti-CD47 agents. Rapid dissemination of knowledge of these monoclonal antibody agents to the broader transfusion medicine community is paramount for continued patient transfusion safety.