Anti-CD20 antibodies and bendamustine attenuate humoral immunity to COVID-19 vaccination in patients with B-cell non-Hodgkin lymphoma

Serologic responses of COVID-19 vaccine are impaired in patients with B-cell lymphoma, especially those who had recently been treated with anti-CD20 monoclonal antibodies. However, it is still unclear whether those patients develop an immune response following vaccination. We investigated the efficacy of vaccination against SARS-CoV-2 in 171 patients with B-cell non-Hodgkin lymphoma (B-NHL) who received two doses of an mRNA-based COVID-19 vaccine and we compared the efficacy of vaccination to that in 166 healthy controls. Antibody titers were measured 3 months after administration of the second vaccine dose. Patients with B-NHL showed a significantly lower seroconversion rate and a lower median antibody titer than those in healthy controls. The antibody titers showed correlations with the period from the last anti-CD20 antibody treatment to vaccination, the period from the last bendamustine treatment to vaccination and serum IgM level. The serologic response rates and median antibody titers were significantly different between diffuse large B-cell lymphoma (DLBCL) patients in whom anti-CD20 antibody treatment was completed within 9 months before vaccination and follicular lymphoma (FL) patients in whom anti-CD20 antibody treatment was completed within 15 months before vaccination. Moreover, the serologic response rates and median antibody titers were significantly different among FL patients in whom bendamustine treatment was completed within 33 months before vaccination. We demonstrated that B-NHL patients who were recently treated with anti-CD20 antibodies and bendamustine had a diminished humoral response to COVID-19 vaccination. UMIN 000,045,267.

Regulation of B-Cell Receptor Signaling and Its Therapeutic Relevance in Aggressive B-Cell Lymphomas

The proliferation and survival signals emanating from the B-cell receptor (BCR) constitute a crucial aspect of mature lymphocyte's life. Dysregulated BCR signaling is considered a potent contributor to tumor survival in different subtypes of B-cell non-Hodgkin lymphomas (B-NHLs). In the last decade, the emergence of BCR-associated kinases as rational therapeutic targets has led to the development and approval of several small molecule inhibitors targeting either Bruton's tyrosine kinase (BTK), spleen tyrosine kinase (SYK), or phosphatidylinositol 3 kinase (PI3K), offering alternative treatment options to standard chemoimmunotherapy, and making some of these drugs valuable assets in the anti-lymphoma armamentarium. Despite their initial effectiveness, these precision medicine strategies are limited by primary resistance in aggressive B-cell lymphoma such as diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL), especially in the case of first generation BTK inhibitors. In these patients, BCR-targeting drugs often fail to produce durable responses, and nearly all cases eventually progress with a dismal outcome, due to secondary resistance. This review will discuss our current understanding of the role of antigen-dependent and antigen-independent BCR signaling in DLBCL and MCL and will cover both approved inhibitors and investigational molecules being evaluated in early preclinical studies. We will discuss how the mechanisms of action of these molecules, and their off/on-target effects can influence their effectiveness and lead to toxicity, and how our actual knowledge supports the development of more specific inhibitors and new, rationally based, combination therapies, for the management of MCL and DLBCL patients.

Anti-CD19 Chimeric Antigen Receptor T Cells in Combination With Nivolumab Are Safe and Effective Against Relapsed/Refractory B-Cell Non-hodgkin Lymphoma

Chimeric antigen receptor (CAR) T cells are emerging as a novel treatment for patients with refractory/relapsed B-cell non-Hodgkin lymphoma (B-NHL), and combination with PD1 inhibitors may further improve the efficacy of anti-CD19 CAR (CD19 CAR)-T cells in the treatment of lymphomas. In a single-center study, we evaluated the safety and efficacy of a combination therapy with CD19 CAR-T cells and an anti-PD-1 antibody (nivolumab) in patients with relapsed/refractory B-NHL. A total of 11 patients with refractory/relapsed B-NHL were recruited and subsequently received CD19 CAR-T cells and nivolumab. The primary end points were safety and feasibility. The infusions were safe, and no dose-limiting toxicities occurred. Grade 1 or 2 cytokine release syndrome (CRS) was observed in 25% (3/11) and 50% (6/11) of the patients, respectively, and only one patient (1/11) experienced neurotoxicity. The objective response rate (ORR) and complete response (CR) rate were 81.81% (9/11) and 45.45% (5/11), respectively. The median follow-up time was 6 (1~15) months. The median progression-free survival (PFS) time was 6 months (1~14 months), and 3 patients continued to have a response at the time of this writing. Our study demonstrated that the combination of CD19 CAR-T cells and nivolumab was feasible and safe and mediated potent anti-lymphoma activity, which should be examined further in prospective clinical trials in refractory/relapsed B-NHL.