Clinical and Pharmacologic Features of Monoclonal Antibodies and Checkpoint Blockade Therapy in Multiple Myeloma

Identification of three immune molecular subtypes associated with immune profiles, immune checkpoints, and clinical outcome in multiple myeloma

Purpose

To identify the immune molecular subtype for MM to help achieve individualized and precise targeted therapy.

Methods

The GDC API was used to download the TCGA‐MM profile dataset, which contains 859 samples in total, all of which were anterior to the standard treatment after diagnosis. Moreover, 282, 298, and 258 samples were stage I, stage II, and stage III separately. We used the immune gene expression profile for consistent clustering; and used the R software package ConsensusClusterPlus to sort the immune molecular subtypes. Correlation between subtypes and clinical features, immunity, and prognosis was then analyzed.

Results

A total of 859 tumor samples were separated into these three subtypes, which were not meaningfully related to age or sex but showed a remarkable association with stage. The results suggested that obvious differences in immune metagene expression and expression of 10 immune checkpoint genes appeared among the three subtypes.

Conclusion

The three subtypes are distinctly different in terms of immune metagenes, immune checkpoint molecules, and clinical prognosis. The discovery of the immune microenvironment of MM could further reveal the strategy for immunotherapy in MM and provide a promising candidate prognostic tool for survival.

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.

Monoclonal Antibodies to Treat Multiple Myeloma: A Dream Come True

Immunotherapy is increasingly used in the treatment of multiple myeloma (MM). Monoclonal antibodies (mAbs) are safe and effective ways to elicit immunotherapeutic responses. In 2015, daratumumab has become the first mAb approved by the Food and Drug Administration for clinical use in MM and, in the last 5 years, a lot of clinical and preclinical research has been done to optimize the use of this drug class. Currently, mAbs have already become part of standard-of-care combinations for the treatment of relapsed/refractory MM and very soon they will also be used in the frontline setting. The success of simple mAbs ('naked mAbs') prompted the development of new types of molecules. Antibody-drug conjugates (ADCs) are tumor-targeting mAbs that release a cytotoxic payload into the tumor cells upon antigen binding in order to destroy them. Bispecific antibodies (BiAbs) are mAbs simultaneously targeting a tumor-associated antigen and an immune cell-associated antigen in order to redirect the immune cell cytotoxicity against the tumor cell. These different constructs produced solid preclinical data and promising clinical data in phase I/II trials. The aim of this review article is to summarize all the recent developments in the field, including data on naked mAbs, ADCs and BiAbs.

Daratumumab-225Actinium conjugate demonstrates greatly enhanced antitumor activity against experimental multiple myeloma tumors

Daratumumab is an anti-CD38 directed monoclonal antibody approved for the treatment of multiple myeloma (MM) and functions primarily via Fc-mediated effector mechanisms such as complement-dependent cytotoxicity (CDC), antibody-dependent cell cytotoxicity (ADCC), antibody-dependent cellular phagocytosis, and T-cell activation. However, not all patients respond to daratumumab therapy and management of MM remains challenging. Radioimmunotherapy with alpha particle-emitting radionuclides represents a promising approach to significantly enhance the potency of therapeutic antibodies in cancer treatment. Here we report the results of mechanistic and feasibility studies using daratumumab radiolabeled with an alpha-emitter ²²⁵Actinium for therapy of MM.

CD38-positivelymphoma Daudi cell line and MM cell lines KMS-28BM and KMS-28PE were treated in vitro with ²²⁵Ac-daratumumab. ²²⁵Ac-daratumumab Fc-functional properties were assessed with C1q binding and ADCC assays. The pharmacokinetics and tumor uptake of ¹¹¹In-daratumumab in Daudi tumor-bearing severe combined immunodeficiency (SCID) mice were measured with microSPECT/CT. The therapeutic effects of ²²⁵Ac-daratumumab on Daudi and KSM28BM tumors in mice and treatment side effects were evaluated for 50 days posttreatment. The safety of ²²⁵Ac-labeled antimurine CD38 mAb in immunocompetent mice was also evaluated.

²²⁵Ac-daratumumab efficiently and specifically killed CD38-positive tumor cells in vitro, while its complement binding and ADCC functions remained unaltered. MicroSPECT/CT imaging demonstrated fast clearance of the radiolabeled daratumumab from the circulation and tissues, but prolonged retention in the tumor up to 10 days. Therapy and safety experiments with ²²⁵Ac-daratumumab showed a significant increase in the antitumor potency in comparison to naked antibody without any significant side effects.

Our results highlight the potential of targeting alpha-emitters to tumors as a therapeutic approach and suggest that ²²⁵Ac-daratumumab may be a promising therapeutic strategy for the treatment of hematologic malignancies.

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.