Efficacy and safety of elotuzumab for the treatment of multiple myeloma

Immunotherapy of Multiple Myeloma: Promise and Challenges

Whereas the treatment of MM was dependent solely on alkylating agents and corticosteroids during the prior three decades, the landscape of therapeutic measures to treat the disease began to expand enormously early in the current century. The introduction of new classes of small-molecule drugs, such as proteasome blockers (bortezomib and carfilzomib), immunomodulators (lenalidomide and pomalidomide), nuclear export inhibitors (selinexor), and histone deacetylase blockers (panobinostat), as well as the application of autologous stem cell transplantation (ASCT), resulted in a seismic shift in how the disease is treated. The picture changed dramatically once again starting with the 2015 FDA approval of two monoclonal antibodies (mAbs) - the anti-CD38 daratumumab and the anti-SLAMF7 elotuzumab. Daratumumab, in particular, has had a great impact on MM therapy and today is often included in various regimens to treat the disease, both in newly diagnosed cases and in the relapse/refractory setting. Recently, other immunotherapies have been added to the arsenal of drugs available to fight this malignancy. These include isatuximab (also anti-CD38) and, in the past year, the antibody-drug conjugate (ADC) belantamab mafodotin and the chimeric antigen receptor (CAR) T-cell product idecabtagene vicleucel (ide-cel). While the accumulated benefits of these newer agents have resulted in a doubling of the disease's five-year survival rate to more than 5 years and improved quality of life, the disease remains incurable. Almost without exception patients experience relapse and/or become refractory to the drugs used, making the search for innovative therapies all the more essential. This review covers the current scope of anti-myeloma immunotherapeutic agents, both those in clinical use and on the horizon, including naked mAbs, ADCs, bi- and multi-targeted mAbs, and CAR T-cells. Emphasis is placed on the benefits of each along with the challenges that need to be overcome if MM is to be considered curable in the future.

NKG2D-CAR-transduced natural killer cells efficiently target multiple myeloma

CAR-T-cell therapy against MM currently shows promising results, but usually with serious toxicities. CAR-NK cells may exert less toxicity when redirected against resistant myeloma cells. CARs can be designed through the use of receptors, such as NKG2D, which recognizes a wide range of ligands to provide broad target specificity. Here, we test this approach by analyzing the antitumor activity of activated and expanded NK cells (NKAE) and CD45RA- T cells from MM patients that were engineered to express an NKG2D-based CAR. NKAE cells were cultured with irradiated Clone9.mbIL21 cells. Then, cells were transduced with an NKG2D-4-1BB-CD3z-CAR. CAR-NKAE cells exhibited no evidence of genetic abnormalities. Although memory T cells were more stably transduced, CAR-NKAE cells exhibited greater in vitro cytotoxicity against MM cells, while showing minimal activity against healthy cells. In vivo, CAR-NKAE cells mediated highly efficient abrogation of MM growth, and 25% of the treated mice remained disease free. Overall, these results demonstrate that it is feasible to modify autologous NKAE cells from MM patients to safely express a NKG2D-CAR. Additionally, autologous CAR-NKAE cells display enhanced antimyeloma activity demonstrating that they could be an effective strategy against MM supporting the development of NKG2D-CAR-NK-cell therapy for MM.

Monoclonal Antibodies and Multiple Myeloma: All in All It's Just Another Brick in the Wall?

This commentary offers insight about the recent review by the European Medicines Agency on the approval of daratumumab for the treatment of adult patients with multiple myeloma.

Antibody-based delivery of tumor necrosis factor (L19-TNFα) and interleukin-2 (L19-IL2) to tumor-associated blood vessels has potent immunological and anticancer activity in the syngeneic J558L BALB/c myeloma model

PURPOSE

To analyze the impact of TNFα or IL2 on human lymphocytes in vitro and the anti-tumor and immune-modifying effects of L19-IL2 and L19-TNFα on subcutaneously growing J558L myeloma in immunocompetent mice.

METHODS

PBMCs from three healthy volunteers were incubated with IL2, TNFα, or with IL2 plus addition of TNFα (final 20 h). BALB/c J558L mice with subcutaneous tumors were treated with intravenous L19-TNFα plus L19-IL2, or controls. Tumor growth and intra- and peri-tumoral tissues were analyzed for micro-vessel density, necrosis, immune cell composition, and PD1 or PD-L1 expressing cells.

RESULTS

Exposure of PBMC in vitro to IL2, TNFα, or to IL2 over 3 and 5 days plus TNFα for the final 20 h resulted in an approximately 50 and 75% reduction of the CD25low effector cell/CD25high Treg cell ratio, respectively, compared to medium control. IL2 or TNFα increased the proportion of CD4- CD25low effector lymphocytes while reducing the proportion of CD4+ CD25low Teff cells. In the J558L myeloma model, tumor eradication was observed in 58, 42, 25, and 0% of mice treated with L19-TNFα plus L19-IL2, L19-TNFα, L19-IL2, and PBS, respectively. L19-TNFα/L19-IL2 combination caused tumor necrosis, capillary density doubling, peri-tumoral T cell and PD1+ T cell reduction (- 50%), and an increase in PD-L1+ myeloma cells.

CONCLUSION

IL2, TNFα, or IL2 plus TNFα (final 20 h) increased the proportion of CD4- CD25low effector lymphocytes possibly indicating immune activation. L19-TNFα/L19-IL2 combination therapy eradicated tumors in J558L myeloma BALB/c mice likely via TNFα-induced tumor necrosis and L19-TNFα/L19-IL2-mediated local cellular immune reactions.