Immune Reconstitution following High-Dose Chemotherapy and Autologous Stem Cell Transplantation with or without Pembrolizumab Maintenance Therapy in Patients with Lymphoma

Reconstitution of double-negative T cells after cord blood transplantation and its predictive value for acute graft-versus-host disease

BACKGROUND

With an increasing number of patients with hematological malignancies being treated with umbilical cord blood transplantation (UCBT), the correlation between immune reconstitution (IR) after UCBT and graft-versus-host disease (GVHD) has been reported successively, but reports on double-negative T (DNT) cell reconstitution and its association with acute GVHD (aGVHD) after UCBT are lacking.

METHODS

A population-based observational study was conducted among 131 patients with hematological malignancies who underwent single-unit UCBT as their first transplant at the Department of Hematology, the First Affiliated Hospital of USTC, between August 2018 and June 2021. IR differences were compared between the patients with and without aGVHD.

RESULTS

The absolute number of DNT cells in the healthy Chinese population was 109 (70-157)/μL, accounting for 5.82 (3.98-8.19)% of lymphocytes. DNT cells showed delayed recovery and could not reach their normal levels even one year after transplantation. Importantly, the absolute number and percentage of DNT cells were significantly higher in UCBT patients without aGVHD than in those with aGVHD within one year ( F = 4.684, P = 0.039 and F = 5.583, P = 0.026, respectively). In addition, the number of DNT cells in the first month after transplantation decreased significantly with the degree of aGVHD increased, and faster DNT cell reconstitution in the first month after UCBT was an independent protective factor for aGVHD (HR = 0.46, 95% confidence interval [CI]: 0.23-0.93; P = 0.031).

CONCLUSIONS

Compared to the number of DNT cells in Chinese healthy people, the reconstitution of DNT cells in adults with hematological malignancies after UCBT was slow. In addition, the faster reconstitution of DNT cells in the early stage after transplantation was associated with a lower incidence of aGVHD.

Effectiveness and Safety of Pembrolizumab in Recurrent and Relapsed Classic Hodgkin Lymphoma: A Systematic Review

Classical Hodgkin lymphoma (cHL) has achieved high cure rates as a result of recent advancements in treatment. However, recurring or relapsed illness still poses a therapeutic challenge. Immune checkpoint inhibitor pembrolizumab, which targets PD-1, is now being commonly used as part of immunotherapy for recurrent and relapsed cHL. We found eight appropriate articles through systematic search and conducted in-depth analysis to find insights into the effectiveness and safety profiles of pembrolizumab by analyzing clinical trial data in patients with recurrent and relapsed cHL. Analysis of the studies shows that response rates, progression-free survival, and patient-reported quality of life have all significantly improved. However, immune-related consequences are among the adverse outcomes. The necessity for continued study is highlighted by the variation in reported adverse events and follow-up times. Clinicians, researchers, and other healthcare professionals can use this study as a resource to provide knowledgeable and individualized patient care in cHL.

The Tumor Microenvironment in Classic Hodgkin's Lymphoma in Responder and No-Responder Patients to First Line ABVD Therapy

Although classical Hodgkin lymphoma (CHL) is typically curable, 15-25% of individuals eventually experience a relapse and pass away from their disease. In CHL, the cellular microenvironment is constituted by few percent of H/RS (Hodgkin/Reed-Sternberg) tumor cells surrounded from a heterogeneous infiltration of inflammatory cells. The interplay of H/RS cells with other immune cells in the microenvironment may provide novel strategies for targeted immunotherapies. In this paper we analyzed the microenvironment content in CHL patients with responsive disease (RESP) and patients with relapsed/refractory disease to treatment (REL). Our results indicate the increase of CD68⁺ and CD163⁺ macrophages, the increase of PDL-1⁺ cells and of CD34⁺ microvessels in REL patients respective to RESP patients. In contrast we also found the decrease of CD3⁺ and of CD8⁺ lymphocytes in REL patients respective to RESP patients. Finally, in REL patients our results show the positive correlation between CD68⁺ macrophages and PDL-1⁺ cells as well as a negative correlation between CD163⁺ and CD3⁺.

Immunotherapy for Hodgkin lymphoma: From monoclonal antibodies to chimeric antigen receptor T-cell therapy

Although up to 80 % of Hodgkin lymphoma (HL) patients are cured with first-line therapy, relapsed/refractory HL remains a major clinical obstacle and is fatal for patients who are not candidates for autologous stem cell transplantation (ASCT) or relapse after treatment. Several immune-based approaches have been investigated in recent years with the aim of exerting a possible antitumor effect through the immune system response to cancer cells. Clinical studies on novel agents, including brentuximab vedotin (BV) and PD-1 inhibitors, have successfully demonstrated their effectiveness in relapsed disease after ASCT. Additionally, studies examining combination strategies with the goal of reducing the risk of relapse and chemotherapy-related toxicity have showed encouraging results, mainly in untreated early unfavorable or advanced stage classical HL (cHL). Other non-approved immunotherapies such as camidanlumab tesirine, bispecific CD30/CD16A antibody, and CD30 chimeric antigen receptor (CAR) T-cell therapy are promising approaches that may reinforce the therapeutic arsenal available to patients.

Reactivation of natural killer cells with monoclonal antibodies in the microenvironment of malignant neoplasms

Natural killer cells are critical players in the antitumor immune response due to their ability to destroy target cells through cytotoxic activity and other means. However, this response is inhibited in the tumor microenvironment, where a crippling hypoxic environment and several inhibitory molecules bind to NK cells to trigger an anergic state. Inhibitory receptors such as PD-1, NK2GA, KIR, TIGIT, and LAG-3 have been associated with inhibition of NK cells in multiple cancer types. Binding to these receptors leads to loss of cytotoxicity, lower proliferation and metabolic rates, and even apoptosis. While these receptors are important for avoiding auto-immunity, in a pathological setting like malignant neoplasms they are disadvantageous for the individual's immune system to combat cancer cells. The use of monoclonal antibodies to block these receptors contributes to cancer therapy by preventing the inhibition of NK cells. In this review, the impact of NK cell inhibition and activation on cancer therapy was summarized and an overview of the blockade of inhibitory pathways by monoclonal antibodies was provided.

Anti-PD1 Consolidation in Patients with Hodgkin Lymphoma at High Risk of Relapse after Autologous Stem Cell Transplantation: A Multicenter Real-Life Study

(1) Background: Consolidation therapy is an emerging strategy for patients with relapsed/refractory (RR) Hodgkin Lymphoma (HL) at high risk of failing salvage autologous stem cell transplantation (ASCT). (2) Objectives: To assess the safety and effectiveness of PD1-blockade consolidation for these high-risk patients. (3) Design: Multi-center retrospective analysis. (4) Methods: We identified 26 patients given anti-PD1 consolidation, from June 2016 to May 2020. (5) Results: Patients displayed the following risk factors: refractory disease (69%), relapse < 12 months from upfront therapy (15%), ≥2 lines of salvage therapy (73%), extranodal disease (65%). Nineteen patients (73%) had ≥3 of these factors. In addition, 16 patients (61%) also displayed PET-positive (Deauville ≥ 4) disease before ASCT. Treatment-related adverse events (TRAEs), never graded > 3, occurred in 12 patients (46.15%) and mainly included skin rashes (41.7%), transaminitis (33.3%), and thyroid hypofunction (25%). Patients completed a median of 13 courses (range 6−30). At a median follow-up of 25.8 months post-ASCT, the median progression-free (PFS) was 42.6 months, with a 2-year PFS and overall survival rates of 79% and 87%, respectively. (6) Conclusions: Post-ASCT consolidation with anti-PD1 is feasible and effective. Further studies are warranted to define the optimal treatment length and patients’ subsets more likely to benefit from this approach.

Updates in the Role of Checkpoint Inhibitor Immunotherapy in Classical Hodgkin's Lymphoma

Classical Hodgkin's lymphoma is a highly curable disease, but 10-25% of patients with higher-risk disease relapse. The introduction of checkpoint inhibitors (CPIs) targeting PD-1 have changed the landscape of treatment for patients with relapsed/refractory disease to multiple lines of therapy. The depth of response to CPI as a monotherapy is highest in the first relapse as salvage therapy based on outcomes reported in several phase II studies. With earlier use of CPI and brentuximab vedotin, the optimal sequencing of therapy is evolving. In this review, we will summarize clinical investigation of anti-PD-1 mAb in earlier line settings to provide insights on utilizing these agents as chemotherapy- and radiation-sparing approaches, increasing depth of response, and as part of combination regimens.