Single-agent MOR208 salvage and maintenance therapy in a patient with refractory/relapsing diffuse large B-cell lymphoma: a case report

Anti-CD19 monoclonal antibodies for the treatment of relapsed or refractory B-cell malignancies: a narrative review with focus on diffuse large B-cell lymphoma

PURPOSE

CD19 is a cell surface protein that is found on both healthy and malignant B cells. Accordingly, it has become an important target for novel treatments for non-Hodgkin lymphomas and B-cell leukaemia. Three anti-CD19 monoclonal antibodies with distinct mechanisms of action have been developed for the treatment of B-cell malignancies.

METHODS

We reviewed the preclinical and clinical data on the development of the newly approved anti-CD19 monoclonal antibodies blinatumomab, tafasitamab and loncastuximab tesirine, and consider their place in the treatment of relapsed or refractory B-cell malignancies.

RESULTS

Blinatumomab is a bispecific T-cell engager that binds to both CD19 on B cells and CD3 on T cells, facilitating antibody-dependent cytotoxicity. Blinatumomab significantly prolongs overall survival in patients with relapsed or refractory B-cell acute lymphoblastic leukaemia, although cytokine release syndrome and severe neurotoxicity may necessitate discontinuation. Tafasitamab, which has modified anti-CD19 Fab and Fc regions, has significantly enhanced affinity for both CD19 and effector cell receptors compared with unmodified anti-CD19. In L-MIND, tafasitamab plus lenalidomide provided an overall response rate (ORR) of 57.5% in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) in patients non-transplant eligible. Loncastuximab tesirine is an antibody-drug conjugate that has been studied as monotherapy and in combination with ibrutinib in 3L + relapsed or refractory DLBCL. The ORR was 48.3% in a phase II trial of loncastuximab tesirine. The optimal place of anti-CD19 monoclonal antibodies in therapy has yet to be determined, but the prospect of improved outcomes for at least some patients with treatment-resistant B-cell malignancies appears likely, particularly in those with limited therapeutic options and poor prognosis.

Safety of the Anti-CD19 antibody Tafasitamab in Long Term Responders from A Phase II Trial for Relapsed Lymphoma

BACKGROUND

Information about the long-term tolerability of tafasitamab is still limited.

METHODS

5 of 92 patients treated within a phase IIa study of single-agent tafasitamab in relapsed or refractory B NHL were followed for up to five years or longer for long-term tolerability.

RESULTS

Treatment was very well tolerated in an outpatient setting with no hospitalizations needed and mild and tolerable adverse events that occurred mostly within the first two years of treatment.

CONCLUSIONS

Given the excellent tolerability and efficacy of tafasitamab this agent can be used to induce remission in relapsed or refractory lymphoma either alone or in combination with chemotherapy.

Tafasitamab: First Approval

Tafasitamab (tafasitamab-cxix; MONJUVI^®) is an Fc-modified (i.e. two amino acid substitutions within the Fc region, resulting in increased Fcγ receptor affinity), humanized, anti-CD19 monoclonal antibody. Developed by MorphoSys AG, under a license from Xencor, it received accelerated approval (in July 2020) for use in combination with lenalidomide as a treatment for adults with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) not otherwise specified, including DLBCL arising from low grade lymphoma, and who are not eligible for autologous stem cell transplantation (ASCT). It is the first therapy to be approved as a second-line treatment for this patient population in the USA. The recommended dose of tafasitamab is 12 mg per kg of bodyweight, administered via an intravenous infusion. A regulatory assessment for tafasitamab plus lenalidomide for the treatment of adults with relapsed or refractory DLBCL is currently underway in the EU. Tafasitamab is also being clinically investigated as a therapeutic option in various other B-cell malignancies, including follicular lymphoma and other indolent non-Hodgkin's lymphoma. This article summarizes the milestones in the development of tafasitamab leading to this first approval for its use in combination with lenalidomide in adults with relapsed or refractory DLBCL.

Complement System: a Neglected Pathway in Immunotherapy

Approved for the treatment of autoimmune diseases, hematological malignancies, and solid cancers, several monoclonal antibodies (mAb) make use of complement in their mechanism of action. Such an assessment is based on comprehensive investigations that used mouse models, in vitro studies, and analyses from patients at initiation (basal level to highlight deficiencies) and after treatment initiation (mAb impact on complement), which have further provided key insights into the importance of the complement activation and/or complement deficiencies in mAb activity. Accordingly, new approaches can now be developed with the final objective of increasing the clinical efficacy of mAb. These improvements include (i) the concurrent administration of fresh frozen plasma during mAb therapy; (ii) mAb modifications such as immunoglobulin G subclass switching, Fc mutation, or IgG hexamerization to improve the fixation and activation of C1q; (iii) optimization of the target recognition to induce a higher complement-dependent cytotoxicity (CDC) and/or complement-dependant cellular cytotoxicity (CDCC); and (iv) the control of soluble and cellular complement inhibitors.