Low-dose pembrolizumab induced remission in patients with refractory classical Hodgkin lymphoma

Dosing Regimens of Immune Checkpoint Inhibitors: Attempts at Lower Dose, Less Frequency, Shorter Course

Immune checkpoint inhibitors (ICIs) are a revolutionary breakthrough in the field of cancer by modulating patient's own immune system to exert anti-tumor effects. The clinical application of ICIs is still in its infancy, and their dosing regimens need to be continuously adjusted. Pharmacokinetic/pharmacodynamic studies showed a significant plateau in the exposure-response curve, with high receptor occupancy and plasma concentrations achieved at low dose levels. Coupled with concerns about drug toxicity and heavy economic costs, there has been an ongoing quest to reevaluate the current ICI dosing regimens while preserving maximum clinical efficacy. Many clinical data showed remarkable anticancer effects with ICIs at the doses far below the approved regimens, indicating the possibility of dose reduction. Our review attempts to summarize the clinical evidence for ICIs regimens with lower-dose, less-frequency, shorter-course, and provide clues for further ICIs regimen optimization.

Pharmacokinetic Simulation Analysis of Less Frequent Nivolumab and Pembrolizumab Dosing: Pharmacoeconomic Rationale for Dose Deescalation

Nivolumab and pembrolizumab, anti-programmed cell death protein 1 monoclonal antibodies, have revolutionized oncology but are expensive. Using an interventional pharmacoeconomic approach, these drugs can be administered less often to reduce costs and increase patient convenience while maintaining efficacy. Both drugs are good candidates for less frequent dosing because of long half-lives and no evidence of a relationship of dose to efficacy. Established population pharmacokinetic models for both nivolumab and pembrolizumab were used to simulate profiles for multiple dosing regimens on 1000 randomly generated virtual patients. Simulations were initially performed on standard dose regimens to validate these in silico predictions. Next, simulations of nivolumab 0.3 mg/kg every 3 weeks revealed that >95% of patients maintained ≥1.5 μg/mL at steady state, which was inferred as the minimum effective concentration (MEC) for both drugs. Various alternative dosing regimens were simulated for both drugs to determine which regimen(s) can maintain this MEC in >95% of patients. Extended dosing regimens of nivolumab 240 mg every 4 weeks and 480 mg every 8 weeks along with pembrolizumab 200 mg every 6 weeks were simulated, showing that >95% of patients maintained MEC or greater. These simulations demonstrate the potential to reduce drug exposure by at least 50%, thus substantially reducing patient visits (as well as costs), while maintaining equivalent efficacy. These models provide the scientific justification for an ongoing prospective randomized clinical trial comparing standard interval fixed dosing with extended interval fixed dosing, and ultimately an efficacy-driven comparative trial.

Sintilimab for relapsed/refractory extranodal NK/T cell lymphoma: a multicenter, single-arm, phase 2 trial (ORIENT-4)

This study (ORIENT-4) aimed to assess the efficacy and safety of sintilimab, a humanized anti-PD-1 antibody, in patients with relapsed/refractory extranodal NK/T cell lymphoma (r/r ENKTL). ORIENT-4 is a multicenter, single-arm, phase 2 clinical trial (NCT03228836). Patients with r/r ENKTL who failed to at least one asparaginase-based regimen were enrolled to receive sintilimab 200 mg intravenously every 3 weeks for up to 24 months. The primary endpoint was the objective response rate (ORR) based on Lugano 2014 criteria. Twenty-eight patients with r/r ENKTL were enrolled from August 31, 2017 to February 7, 2018. Twenty-one patients (75.0%, 95% CI: 55.1-89.3%) achieved an objective response. With a median follow-up of 30.4 months, the median overall survival (OS) was not reached. The 24-month OS rate was 78.6% (95% CI, 58.4-89.8%). Most treatment-related adverse events (TRAEs) were grade 1-2 (71.4%), and the most common TRAE was decreased lymphocyte count (42.9%). Serious adverse events (SAEs) occurred in 7 (25.0%) patients, and no patient died of adverse events. Sintilimab is effective and well tolerated in patients with r/r ENKTL and could be a novel therapeutic approach for the control of ENKTL in patients.

Biology and Molecular Pathogenesis of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) constitute a highly heterogeneous group of hematological diseases with complex clinical and molecular features consistent with the diversity of the T-cell type from which they originate. In the past several years, the systematic implementation of high-throughput genomic technologies for the analysis of T-cell malignancies has supported an exponential progress in our understanding of the genetic drivers of oncogenesis and unraveled the molecular complexity of these diseases. Recent findings have helped redefine the classification of T-cell malignancies and provided novel biomarkers to improve diagnosis accuracy and analyze the response to therapy. In addition, multiple novel targeted therapies including small-molecule inhibitors, antibody-based approaches, and immunotherapy have shown promising results in early clinical analysis and have the potential to completely change the way T-cell malignancies have been treated traditionally.

Combined immune checkpoint blockade and radiotherapy induces durable remission in relapsed natural killer/T-cell lymphoma: a case report and review of the literature

BACKGROUND

Extranodal natural killer/T-cell lymphoma is a rare, aggressive non-Hodgkin lymphoma that is treated upfront mostly with L-asparaginase containing regimens. Relapsed extranodal natural killer/T-cell lymphoma is associated with a poor prognosis, and there is no established standard of care.

CASE PRESENTATION

We report the case of a 72 year-old white male with a distant extranasal relapse of extranodal natural killer/T-cell lymphoma that has been managed successfully with a combination of radiation and immune checkpoint blockade with pembrolizumab. Pseudoprogression with new skin and bone lesions on positron emission tomography imaging was encountered during this Caucasian patient's immunotherapy and was successfully managed with supportive care and continuation of immune checkpoint blockade.

CONCLUSIONS

The patient has been in complete clinical, radiologic, and molecular remission for close to 3 years and has not had any immune-related adverse effects. Pseudoprogression is a clinical challenge that can be encountered while patients are treated with immunotherapy, and astute clinical acumen is needed for accurate management. We believe this is the longest duration of response to immune checkpoint blockade in relapsed extranodal natural killer/T-cell lymphoma reported to date in literature. There is a strong biologic rationale in combining radiation with immunotherapy. The optimal timing, dose, and duration of radiation combined with immunotherapy in extranodal natural killer/T-cell lymphoma need to be prospectively evaluated.

The Right Dose: From Phase I to Clinical Practice

To realize the full potential of promising new anticancer drugs, it is of paramount importance to administer them at the right dose. The aim of this educational article is to provide several opportunities to optimize anticancer drug dosing, focusing on oral targeted therapies. First, therapeutic drug monitoring can optimize exposure in individual patients, if the optimal concentration is known. This approach is of particular interest in regard to oral kinase inhibitors with high interindividual pharmacokinetic variability. If exposure is related to response, then therapeutic drug monitoring is potentially feasible, although the clinical utility of this approach has not yet been established. Other approaches to reduce variability include administration of more frequent, smaller doses and administration under optimal prandial conditions. However, for many drugs, the labeled dose has not been demonstrated to be the optimal dose; for such agents, the vast majority of patients may be receiving excessive doses, which results in excessive toxicity. Furthermore, administration of lower off-label doses may reduce both medical and financial toxicity. These strategies should be applied from registration studies to clinical practice, with the goal of better optimizing anticancer treatment.

Low-dose pembrolizumab and nivolumab were efficacious and safe in relapsed and refractory classical Hodgkin lymphoma: Experience in a resource-constrained setting

The efficacy and safety of low-dose anti-PD1 antibodies in relapsed/refractory classical Hodgkin lymphoma (cHL) require confirmation. Pembrolizumab (100 mg every 3 weeks, Q3W) or nivolumab (40 mg Q2W) were administered to patients with relapsed/refractory cHL. In the pembrolizumab cohort (N = 11), who had failed a median of three (1-6) therapies (brentuximab vedotin [BV]: 91%; autologous hematopoietic stem cell transplantation [auto-HSCT]: 18%), the overall response rate (ORR) by positron emission tomography-computed tomography was 100% (metabolic complete response [mCR]: 73%; partial response [PR]: 27%). Median cumulative dose for achieving best response was 400 (300-800) mg. Median progression-free survival (PFS) was 35 months. Median overall survival (OS) was not reached. Adverse events (AEs) of grade 1-2 were observed in three patients. In the nivolumab cohort (N = 6), who had failed a median of three (2-6) therapies (BV: 50%; auto-HSCT: 17%; allogeneic HSCT: 34%), the ORR was 100% (mCR: 67%; PR: 17%; indeterminate response: 17%). Median cumulative dose for achieving best response was 160 (160-360) mg. Median PFS was 33 months. Median OS was not reached. AEs of grade 1-2 were observed in four patients, two of whom had pre-existing autoimmune conditions. Five patients with Epstein-Barr virus (EBV) positive Reed-Sternberg cells underwent monitoring of plasma EBV DNA, which became negative in four mCR patients but remained positive in one PR patient who died ultimately from refractory lymphoma. Low-dose pembrolizumab and nivolumab were highly efficacious and safe in relapsed/refractory cHL. These observations have significant financial implications in resource-constrained settings.

Immune Checkpoint Inhibitors to Treat Malignant Lymphomas

Genetic and/or epigenetic changes provide antigen-derived diversity in neoplastic cells. Beside, these cells do not initiate immune response of host organisms. A variety of factors are responsible for the resistant to treatment, including individual variations in patients and somatic cell genetic differences in tumors, even those from the same tissue of origin. Immune system is controlled by several controlling mechanisms. Recently, a significant progress in hematologic treatment has been made; however, majority of diseases still remain incurable. Immunotherapy with checkpoint inhibitors has emerged as promising modality of antitumor treatment, showing marked response to several antigens, including cytotoxic T lymphocyte-associate protein-4 (CTLA-4) or programmed cell death 1 receptor (PD-1). In this review, we demonstrate actual knowledge on immune checkpoint function and its impact on development of new modality of antineoplastic treatment, using, for example, anti-CTLA-4 or PD-1/PD1 ligand (PD-L1) monoclonal antibodies in malignant lymphomas.

Pembrolizumab for recurrent/metastatic head and neck squamous cell carcinoma in an Asian population

Head and neck squamous cell carcinoma (HNSCC) has a high prevalence and is a major cause of cancer deaths in Taiwan. However, there is still no effective salvage therapy that prolongs the life expectancy of patients with recurrent/metastatic (R/M) HNSCC. Immune checkpoint therapy that targets the programmed cell death protein 1 (PD-1) may provide clinical benefit for these patients. We analyzed 22 R/M HNSCC patients who received pembrolizumab, a monoclonal antibody against PD-1, as salvage therapy. Intravenous pembrolizumab was given at a fixed dosage of 100 or 200 mg every 3 weeks. Three patients also received local palliative radiotherapy, but no patients received chemotherapy or targeted drugs. Seventeen patients (77.3%) received at least 3 cycles of pembrolizumab. Based on Response Evaluation Criteria in Solid Tumors criteria (ver. 1.1), 2 patients (9.1%) had complete response, 5 (22.7%) had partial response, and 6 (27.3%) had stable disease, corresponding to a disease control rate of 59.1%. Four patients had confirmed disease progression, 2 of whom had continuous progression over the target lesion after shrinkage of other metastases. One patient developed immune-related pneumonitis that resolved quickly after steroid treatment. Another patient developed itchy skin rashes immediately after administration of pembrolizumab, and this was controlled by an antihistamine. There were no other severe adverse effects. Pembrolizumab is beneficial and well-tolerated for some patients with refractory R/M HNSCC. However, it is important to identify biomarkers to identify the most responsive patients when designing future trials.

PD1 blockade with pembrolizumab is highly effective in relapsed or refractory NK/T-cell lymphoma failing l-asparaginase

Natural killer (NK)/T-cell lymphomas failing L-asparaginse regimens have no known salvage and are almost invariably fatal. Seven male patients with NK/T-cell lymphoma (median age, 49 years; range, 31-68 years) for whom a median of 2 (range, 1-5) regimens (including l-asparaginase regimens and allogeneic hematopoietic stem-cell transplantation [HSCT] in 2 cases) failed were treated with the anti-programmed death 1 (PD1) antibody pembrolizumab. All patients responded, according to various clinical, radiologic (positron emission tomography), morphologic, and molecular (circulating Epstein-Barr virus [EBV] DNA) criteria. Two patients achieved complete response (CR) in all parameters. Three patients achieved clinical and radiologic CRs, with two having molecular remission (undetectable EBV DNA) but minimal EBV-encoded RNA-positive cells in lesions comprising predominantly CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells (which ultimately disappeared, suggesting they represented pseudoprogression) and one having detectable EBV DNA despite morphologic CR. Two patients achieved partial response (PR). After a median of 7 (range, 2-13) cycles of pembrolizumab and a follow-up of a median of 6 (range, 2-10) months, all five CR patients were still in remission. The only adverse event was grade 2 skin graft-versus-host disease in one patient with previous allogeneic HSCT. Expression of the PD1 ligand was strong in 4 patients (3 achieving CR) and weak in 1 (achieving PR). PD1 blockade with pembrolizumab was a potent strategy for NK/T-cell lymphomas failing l-asparaginase regimens.

Pembrolizumab (Keytruda)

The programmed cell death protein 1 (PD1) is one of the checkpoints that regulates the immune response. Ligation of PD1 with its ligands PDL1 and PDL2 results in transduction of negative signals to T-cells. PD1 expression is an important mechanism contributing to the exhausted effector T-cell phenotype. The expression of PD1 on effector T-cells and PDL1 on neoplastic cells enables tumor cells to evade anti-tumor immunity. Blockade of PD1 is an important immunotherapeutic strategy for cancers. Pembrolizumab (Keytruda) is a humanized monoclonal anti-PD1 antibody that has been extensively investigated in numerous malignancies. In melanoma refractory to targeted therapy, pembrolizumab induced overall response rates (ORRs) of 21-34%. It was superior to another immune checkpoint inhibitor ipilimumab (Yervoy) in stage III/IV unresectable melanoma. In refractory non-small cell lung cancer (NSCLC), pembrolizumab induced ORRs of 19-25%. Based on these results, pembrolizumab was approved by the USA FDA for the treatment of advanced melanoma and NSCLC. Tumor cell PDL1 expression may be a valid response predictor. Molecular analysis also showed that tumors with high gene mutation burdens, which might result in the formation of more tumor-related neo-antigens, had better responses to pembrolizumab. In malignancies including lymphomas and other solid tumors, preliminary data showed that ORRs of around 20-50 % could be achieved. Adverse events occurred in up to 60% of patients, but grade 3/4 toxicities were observed in <10% of cases. Immune-related adverse events including thyroid dysfunction, hepatitis and pneumonitis are more serious and may lead to cessation of treatment.

A case report and literature review of primary resistant Hodgkin lymphoma: a response to anti-PD-1 after failure of autologous stem cell transplantation and brentuximab vedotin

Hodgkin lymphoma (HL) is a highly curable hematologic malignancy, and ~70% of cases can be cured with combination chemotherapy with or without radiation. However, patients with primary resistant disease have a cure rate of <30%. For such patients, high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is considered to be the standard treatment. If patients fail to respond to ASCT or relapse soon thereafter, they usually receive another ASCT, allogeneic stem cell transplantation or treatment with novel agents. This case report presents the case of a 54-year-old patient with primary resistant HL who received single-agent treatment, brentuximab vedotin, after ASCT relapse. Despite treatment with brentuximab vedotin, the disease continued to progress. In patients with such highly resistant disease, the treatment options are limited. Depending on the physical condition and the willingness of the patient, pembrolizumab, a programmed cell death protein-1 inhibitor, can be given as salvage therapy. But, out of our expectation, the patient achieved a very good partial response after four cycles of pembrolizumab. No serious adverse events were observed with pembrolizumab treatment. This case provides support for a new and effective strategy for treating primary resistant Hodgkin lymphoma.

Pembrolizumab in classical Hodgkin's lymphoma

Pembrolizumab is a humanized monoclonal antibody directed against programmed cell death protein 1 (PD-1), a key immune-inhibitory molecule expressed on T cells and implicated in CD4+ T-cell exhaustion and tumor immune-escape mechanisms. Classical Hodgkin's lymphoma (cHL) is a unique B-cell malignancy in the sense that malignant Reed-Sternberg (RS) cells represent a small percentage of cells within an extensive immune cell infiltrate. PD-1 ligands are upregulated on RS cells as a consequence of both chromosome 9p24.1 amplification and Epstein-Barr virus infection and by interacting with PD-1 promote an immune-suppressive effect. By augmenting antitumor immune response, pembrolizumab and nivolumab, another monoclonal antibody against PD-1, have shown significant activity in patients with relapsed/refractory cHL as well as an acceptable toxicity profile with immune-related adverse events that are generally manageable. In this review, we explore the rationale for targeting PD-1 in cHL, review the clinical trial results supporting the use of checkpoint inhibitors in this disease, and present future directions for investigation in which this approach may be used.