Evaluation of the pharmacokinetics and metabolism of pembrolizumab in the treatment of melanoma

Application of newly developed and validated LC-MS/MS method for pharmacokinetic study of adagrasib and pembrolizumab simultaneously in rat plasma

Non-small cell lung cancer (NSCLC) is a significant subtype of lung cancer, and poses a dangerous global threat. One of the current approaches of NSCLC treatment is a combination therapy of adagrasib and pembrolizumab. Accurate monitoring of these drug concentrations in biological fluids is critical for treatment efficacy. Since no method was reported for simultaneous estimation of these drugs, this study focuses on the development of a validated LC-MS/MS bioanalytical method for simultaneous quantification of Adagrasib and Pembrolizumab in rat plasma. The analytes were extracted from the biological matrix through liquid-liquid extraction techniques using acetonitrile as extraction solvent. The analytes were separated on a Waters X-bridge phenyl C18 column, with a mixture of acetonitrile: 0.1 % TFA in water (50: 50 v/v) as mobile phase at an isocratic flow rate of 1.0 mL/min with a runtime of about 5 min. Adagrasib (m/z 605.12 → 201.62), Pembrolizumab (m/z 146.32 → 85.15), and Sotorasib (m/z 561.59 → 218.92) were determined by recording the mass spectra through multiple reaction monitoring in positive mode. The method was validated according to USFDA guidelines. The results demonstrate satisfactory linearity with an r2 value of 0.9998 in the ranges of 40-800 and 10-200 ng/mL, accuracy with mean percentage recovery of 95.22-98.59 % and 96.98-98.57 %, precision indicated with %RSD ranged between 0.39-1.91 % and 0.85-9.03 % for Adagrasib and Pembrolizumab respectively, and other key parameters. The developed method can determine the pharmacokinetic parameters to indicate the efficacy and safety of the drugs, and also can quantify selected drugs simultaneously in biological samples.

Dostarlimab in the treatment of mismatch repair deficient recurrent or advanced endometrial cancer

Dostarlimab, a programmed death receptor-1 (PD-1)-blocking IgG4 humanized monoclonal antibody, gained accelerated approval from the US Food and Drug Administration (FDA) in April 2021, and received a full approval in February 2023. Dostarlimab was approved for treating adult patients with mismatch repair deficient (dMMR) recurrent or advanced endometrial cancer (EC) that progressed during or after prior treatment who have no other suitable treatment options. Herein, we review the structure-based mechanism of action of dostarlimab and the results of a clinical study (GARNET; NCT02715284) to comprehensively clarify the efficacy and toxicity of the drug. The efficacy and safety of dostarlimab as monotherapy was assessed in a non-randomized, multicenter, open-label, multi-cohort trial that included 209 patients with dMMR recurrent or advanced solid tumors after receiving systemic therapy. Patients received 500 mg of dostarlimab intravenously every three weeks until they were given four doses. Then, patients received 1000 mg dostarlimab intravenously every six weeks until disease progression or unacceptable toxicity. The overall response rate, as determined by shrinkage in tumor size, was 41.6% (95% confidence interval [CI]; 34.9, 48.6), with 34.7 months as the median response duration. In conclusion, dostarlimab is an immunotherapy-based drug that has shown promising results in adult patients with recurrent or advanced dMMR EC. However, its efficacy in other cancer subtypes, the development of resistance to monotherapy, and efficacy and safety in combination with other immunotherapeutic drugs have not yet been studied.

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Comparison of clinical safety between standard versus extended interval dosing of immune checkpoint inhibitors: a real-world retrospective cohort study

BACKGROUND

Extended interval dosing (ED) for inhibitors of programmed cell death protein 1 (anti-PD-1) (nivolumab, pembrolizumab) or its ligand (anti-PD-L1) (durvalumab) were recently approved based on pharmacokinetic model results that predicted a benefit-risk profile comparable with the standard dosing (SD) regimen. However, safety data in real-world condition of use are lacking. The objective was to compare the incidence and the risk factors of serious immune-related adverse events (irAEs) and any-grade irAEs between the SD and ED regimens in patients treated with anti-PD-1 or anti-PD-L1.

MATERIALS AND METHODS

IrAEs were assessed from medical records in all new users of nivolumab, pembrolizumab, or durvalumab between 1 January 2019 and 31 December 2020 across two oncology centers in France. The incidence of irAEs was compared between both dosing regimens using Cox proportional hazards models adjusting for the main available confounders.

RESULTS

Among 686 patients included, 63% were new users of an SD regimen, 14% of ED regimen, and 23% started with SD and switched to ED regimen during follow-up. Overall, 34.6% of patients experienced at least one irAE of any grade and 11.4% presented at least one serious grade ≥3 irAE. No statistical difference was found between the SD and ED regimen on the risk of grade ≥3 irAEs [adjusted hazard ratio (HR) 1.40, 95% confidence interval (CI) 0.71-2.76] but our results suggest an increased risk of any-grade irAEs with the ED regimen (adjusted HR 1.46, 95% CI 1.00-2.12, P = 0.048). IrAEs resolved without sequelae in 46.4% of cases, and they were fatal for three patients (0.4%). Autoimmune pre-existing condition was confirmed as a risk factor for grade ≥3 irAEs (HR 2.56, 95% CI 1.53-4.27) and for all-grade irAEs (HR 1.60, 95% CI 1.17-2.20).

CONCLUSIONS

In a real-world setting, according to the regimen chosen by the oncologist based on clinical characteristics, we did not observe an increase in grade ≥3 irAE incidence between the SD and ED regimens.

Intratumoral nanofluidic system enhanced tumor biodistribution of PD-L1 antibody in triple-negative breast cancer

Immune checkpoint inhibitors (ICI), pembrolizumab and atezolizumab, were recently approved for treatment-refractory triple-negative breast cancer (TNBC), where those with Programmed death-ligand 1 (PD-L1) positive early-stage disease had improved responses. ICIs are administered systemically in the clinic, however, reaching effective therapeutic dosing is challenging due to severe off-tumor toxicities. As such, intratumoral (IT) injection is increasingly investigated as an alternative delivery approach. However, repeated administration, which sometimes is invasive, is required due to rapid drug clearance from the tumor caused by increased interstitial fluid pressure. To minimize off-target drug biodistribution, we developed the nanofluidic drug-eluting seed (NDES) platform for sustained intratumoral release of therapeutic via molecular diffusion. Here we compared drug biodistribution between the NDES, intraperitoneal (IP) and intratumoral (IT) injection using fluorescently labeled PD-L1 monoclonal antibody (αPD-L1). We used two syngeneic TNBC murine models, EMT6 and 4T1, that differ in PD-L1 expression, immunogenicity, and transport phenotype. We investigated on-target (tumor) and off-target distribution using different treatment approaches. As radiotherapy is increasingly used in combination with immunotherapy, we sought to investigate its effect on αPD-L1 tumor accumulation and systemic distribution. The NDES-treated cohort displayed sustained levels of αPD-L1 in the tumor over the study period of 14 days with significantly lower off-target organ distribution, compared to the IP or IT injection. However, we observed differences in the biodistribution of αPD-L1 across tumor models and with radiation pretreatment. Thus, we sought to extensively characterize the tumor properties via histological analysis, diffusion evaluation and nanoparticles contrast-enhanced CT. Overall, we demonstrate that ICI delivery via NDES is an effective method for sustained on-target tumor delivery across tumor models and combination treatments.

Immune interactions in pembrolizumab (PD-1 inhibitor) cancer therapy and cardiovascular complications

The use of immunotherapies like pembrolizumab (PEM) is increasingly common for the management of numerous cancer types. The use of PEM to bolster T-cell response against tumor growth is well documented. However, the interactions PEM has on other immune cells to facilitate tumor regression and clearance is unknown and warrants further investigation. In this review, we present literature findings that have reported the interactions of PEM in stimulating innate and adaptive immune cells, which enhance cytotoxic phenotypes. This triggers secretion of cytokines and chemokines, which have both beneficial and detrimental effects. We also describe how this leads to the development of rare but underreported occurrence of PEM-induced immune-related cardiovascular complications that arise suddenly and progress rapidly to debilitating and fatal consequences. This review encourages further research and investigation of PEM-induced cardiovascular complications and other immune cell interactions in patients with cancer. As PEM therapy in treating cancer types is expanding, we expect that this review will inform health care professionals of diverse specializations of medicine like dermatology (melanoma skin cancers), ophthalmology (eye cancers), and pathology (hematological malignancies) about PEM-induced cardiac complications.

Advantages of the Combinatorial Molecular Targeted Therapy of Head and Neck Cancer-A Step before Anakoinosis-Based Personalized Treatment

The molecular initiators of Head and Heck Squamous Cell Carcinoma (HNSCC) are complex. Human Papillomavirus (HPV) infection is linked to an increasing number of HNSCC cases, but HPV-positive tumors generally have a good prognosis. External factors that promote the development of HPV-negative HNSCC include tobacco use, excessive alcohol consumption, and proinflammatory poor oral hygiene. On a molecular level, several events, including the well-known overexpression of epidermal growth factor receptors (EGFR) and related downstream signaling pathways, contribute to the development of HNSCC. Conventional chemotherapy is insufficient for many patients. Thus, molecular-based therapy for HNSCC offers patients a better chance at a cure. The first molecular target for therapy of HNSCC was EGFR, inhibited by monoclonal antibody cetuximab, but its use in monotherapy is insufficient and induces resistance. This article describes attempts at combinatorial molecular targeted therapy of HNSCC based on several molecular targets and exemplary drugs/drug candidates. The new concept of anakoinosis-based therapy, which means treatment that targets the intercellular and intracellular communication of cancer cells, is thought to be the way to improve the clinical outcome for HNSCC patients. The identification of a link between molecular targeted therapy and anakoinosis raises the potential for further progress in HPV-negative HNSCC therapy.

A comprehensive update of hormone-related pharmacokinetic variations associated with breast cancer drugs

INTRODUCTION

Drugs available for the treatment of breast cancer are increasing, yielding improved oncological outcomes. The efficacy and safety of anticancer drugs significantly depend on pharmacokinetic profiles, which could be influenced by several factors, such as sex hormones.

AREAS COVERED

This article discusses the potential hormone-related pharmacokinetic influences on novel breast cancer pharmacotherapies.

EXPERT OPINION

Recently approved drugs for the treatment of breast cancer belong to different classes, each with unique pharmacokinetic profile. The impact of hormones, such as estrogen and progesterone, may occur at different steps of drug metabolism. Key effects of sex hormones ha ve been reported on multidrug-resistant transporters and enzymes involved in the liver metabolism of drugs, such as cytochromes. Nevertheless, no data is currently available to establish hormone-related metabolic interactions that may account for variability in drug scheduling and selection. Whereas we recognize influences may occur, we do not assume hormones alone can yield clinically significant metabolic changes. Rather, we believe that hormonal influences should be considered along with other elements that may affect drugs metabolism, such as concomitant medications, age-related pharmacokinetic changes, and genetic polymorphisms, in order to deliver treatment personalization and ensure better tolerability and safety of anticancer treatments.

Immune checkpoint inhibitors in liver transplant: a case series

BACKGROUND

Immune checkpoint inhibitors (ICIs) in the setting of liver transplant (LT) pose a risk of rejection and hold unclear benefit in both the neoadjuvant (pre-transplant) and post-transplant salvage setting. In the pre-transplant setting, neoadjuvant ICIs may serve as a bridge to LT by downstaging disease burden to fit within transplant criteria. Outcomes in this setting include patients who had successful transplants without complications to patients who suffered severe complications, including fatal hepatic necrosis and graft failure requiring re-transplant. Some authors suggest having a period of three months between checkpoint inhibition and transplant may help mitigate adverse effects. In the post-LT setting, there are few treatment options if there is a recurrence of disease, which forces treatment teams to reconsider checkpoint inhibitors. Again, a longer period of time between transplant and checkpoint inhibition may reduce risk of rejection. Case reports of patients treated with ICIs post-transplant utilized either nivolumab or pembrolizumab. As combination atezolizumab/bevacizumab is a relatively new treatment option for unresectable hepatocellular carcinoma (HCC), there are only three reported cases using this combination in the post-LT setting. While there were no cases of rejection, all three cases had progression of disease. As immunotherapy joins transplantation as a mainstay of treatment for HCC, it remains unclear how to best navigate when the treatment course involves both immune activation and immunosuppression.

CASE DESCRIPTION

Patients who had an LT and were treated with ICIs (pre or post LT) at the University of Cincinnati were included in this retrospective chart review.

CONCLUSIONS

Fatal rejection remains a significant risk even 4 years after LT. Neoadjuvant ICIs also pose a risk for acute cellular rejection; however, this may not always be clinically significant. Graft versus host disease (GVHD) may be an additional, previously unreported risk of ICIs in the setting of LT. Prospective studies are needed to understand benefits and risks of checkpoint inhibitors in the LT setting.

Long-term clinical evidence of comparable efficacy and toxicity of nivolumab and pembrolizumab in advanced melanoma treatment

Pembrolizumab and nivolumab (anty-PD-1 antibody) are commonly used for the treatment of melanoma patients. However, their efficacy and safety have never been directly compared, leaving little guidance for clinicians to select the best therapy. The study included patients with inoperable or metastatic melanoma treated in first line with anti-PD-1 immunotherapy (nivolumab or pembrolizumab). In total 1037 patients were enrolled in the study, 455 (44%) patients were treated with pembrolizumab and 582 (56%) with nivolumab. The estimated median overall survival (OS) in the pembrolizumab and nivolumab groups was 17.4 and 20.0 months [P = 0.2323; hazard ratio (HR), 1.1; 95% confidence interval (CI), 0.94-1.28], respectively, whereas the median progression-free survival (PFS) was 5.6 and 7.5 months (P = 0.0941; HR, 1.13; 95% CI, 0.98-1.29), respectively. The estimated 2- and 3-year OS in the pembrolizumab and nivolumab groups were 42/34% and 47/37%, respectively, and the PFS was 25/21% and 29/23%, respectively. There were 391 (49%) immune-related adverse events (irAEs) of any grade during treatment, including 133 (42%) related to pembrolizumab treatment and 258 (53%) to nivolumab treatment. A total of 72 (9.6%) irAEs were in G3 or G4, including during pembrolizumab 29 (9%) and nivolumab 48 (11%). There were no differences in OS, PFS and overall response rates between nivolumab and pembrolizumab therapy in previously untreated patients with advanced/metastatic melanoma. There were no differences in the frequency of G1/G2 or G3/G4 irAEs. The choice of treatment should be based on the preferences of the patient and the clinician.

Advances in pharmacokinetics and pharmacodynamics of PD-1/PD-L1 inhibitors

Immune checkpoint inhibitors (ICIs) are a group of drugs designed to improve the therapeutic effects on various types of malignant tumors. Irrespective of monotherapy or combinational therapies as first-line and later-line therapy, ICIs have achieved benefits for various tumors. Programmed cell death protein-1 (PD-1) / ligand 1 (PD-L1) is an immune checkpoint that suppresses antitumor immunity, especially in the tumor microenvironment (TME). PD-1/PD-L1 immune checkpoint inhibitors block tumor-related downregulation of the immune system, thereby enhancing antitumor immunity. In comparison with traditional small-molecule drugs, ICIs exhibit pharmacokinetic characteristics owing to their high molecular weight. Furthermore, different types of ICIs exhibit different pharmacodynamic characteristics. Hence, ICIs have been approved for different indications by the Food and Drug Administration (FDA) and National Medical Products Administration (NMPA). This review summarizes pharmacokinetic and pharmacodynamic studies of PD-1/ PD-L1 inhibitors to provide a reference for rational clinical application.

Pharmacokinetics and pharmacodynamics of approved monoclonal antibody therapy for colorectal cancer

INTRODUCTION

The introduction of monoclonal antibodies to the chemotherapy backbone treatment has challenged the paradigm of metastatic colorectal cancer (mCRC) treatment. Their mechanism of action and pharmacokinetics are complex but important to understand in order to improve patient selection and treatment outcomes for mCRC population.

AREAS COVERED

This review examines the scientific data, pharmacodynamics, and pharmacokinetics of approved monoclonal antibodies used to treat mCRC patients, including agents targeting signaling via VEGFR (bevacizumab and ramucirumab), EGFR (cetuximab and panitumumab), HER2/3 target therapy, and immunotherapy agents such as pembrolizumab or nivolumab. Efficacy and mechanism of action of bispecific antibodies are also covered.

EXPERT OPINION

mCRC is a heterogeneous disease and the optimal selection and sequence of treatments is challenging. Monoclonal antibodies have complex pharmacokinetics and pharmacodynamics, with important interactions between them. The arrival of bioequivalent molecules to the market increases the need for the characterization of pharmacokinetics and pharmacodynamics of classic monoclonal antibodies to reach bioequivalent novel molecules.

Targeting Indoleamine Dioxygenase and Tryptophan Dioxygenase in Cancer Immunotherapy: Clinical Progress and Challenges

Indoleamine 2.3-dioxygenases (IDO1/2) and tryptophan 2.3-dioxygenase (TDO) are the initial and rate-limiting enzymes in tryptophan metabolism, which play an essential role in mediating immunosuppression in tumor microenvironment. Accumulating evidence has indicated that both IDO1 and TDO are highly expressed in many malignant tumors, and their expression is generally associated with reduced tumor-infiltrating immune cells, increased regulatory T-cell infiltration, as well as cancer progression and poor prognosis for malignancies. A large number of IDO1 and TDO inhibitors have been screened or synthesized in the last two decades. Thus far, at least 12 antagonists targeting IDO1 and TDO have advanced to clinical trials. In this account, we conducted a comprehensive review of the development of IDO1 and TDO inhibitors in cancer immunotherapy, particularly their clinical research progress, and presented the current challenges and corresponding solutions.

Pembrolizumab-Induced Myocarditis and Delayed Acute Inflammatory Demyelinating Polyradiculoneuropathy

Pembrolizumab is an immunotherapeutic agent used in various malignancies including metastatic melanoma. While immunotherapies are effective in treating several malignancies, they do come at the expense of inadvertent side effects. The numerous side effects of pembrolizumab, including, but not limited to, adrenal insufficiency, myocarditis, and pancreatitis, are well documented in clinical literature. In this case report, we describe a unique presentation of myocarditis and acute inflammatory demyelinating polyradiculoneuropathy secondary to pembrolizumab. While both side effects of pembrolizumab are well known, the delayed presentation of symptoms is of particular interest in our case report. We hope to inform the clinical community on the pharmacokinetics of pembrolizumab causing the delayed onset of symptoms.

[Application of MIDD in Clinical Research of Antitumor Drugs]

The antitumor drug has become one of the focused areas in new drug research and development. Their clinical research generally consumes a long period of time, with high cost and high risk. Model-informed drug development (MIDD) integrates and quantitatively analyzes physiological, pharmacological, and disease progression information through modeling and simulation, which can reduce the cost of drug development and improve the efficiency of clinical research. In this essay, Osimertinib and Pembrolizumab are given as examples to illustrate the specific application of MIDD in different phases of clinical research, aiming to provide references for the application of MIDD to guide the clinical research of antitumor drugs.
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Stable liver graft post anti-PD1 therapy as a bridge to transplantation in an adolescent with hepatocellular carcinoma

BACKGROUND

Immunotherapy, specifically immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 (anti-PD1), has recently received clinical approval for the treatment of adult hepatocellular carcinoma (HCC). However, the safety and efficacy of ICIs prior to solid organ transplant are unknown, especially in pediatrics. Safety reports are variable in adults, with some series describing subsequent allograft rejection and loss while others report successful transplants without allograft rejection.As ICIs stimulate the immune system by blocking the interaction between PD1 and the ligand-receptor pair programmed cell death-ligand 1 (PDL1), the downstream effects of T-cell activation increase the risk of graft rejection.

METHODS

Here, we present a case of an adolescent with moderately differentiated non-fibrolamellar HCC treated with pembrolizumab, an anti-PD1 therapy, who subsequently underwent successful orthotopic liver transplantation (OLT).

RESULTS

Our patient received an OLT 138 days from the last pembrolizumab dose with graft preservation. The patient has no evidence of recurrent disease or any episode of allograft rejection 48 months post OLT. Staining of tumor and normal tissues from longitudinal specimens finds PDL1 positive Kupffer cells present in normal liver and peritumoral areas with no changes post anti-PD1 therapy. In contrast, tumor cells were negative for PDL1.

CONCLUSION

This case represents a basis for optimism in potential use of anti-PD1 therapy in liver transplant candidates and supports further investigation of immune checkpoint inhibitors use in this unique patient population.

Hypophysitis secondary to pembrolizumab: a case report and review of the literature

Pembrolizumab is a mAb against the programmed cell death protein-1 (PD-1). It has been approved for the treatment of advanced melanoma (unresectable or metastatic) in adults. Side effects associated with the use of anti-PD-1 are usually considered well tolerated; nevertheless, there are immune-related adverse events that may require treatment discontinuation. A 79-year-old man diagnosed with stage IV right scapular melanoma experienced unspecific symptoms and alterations of the hypothalamus-hypophysis axis after six cycles with pembrolizumab. The case was compatible with immune-related hypophysitis. Autoimmune thyroiditis and primary hypophysitis were excluded and toxicity due to pembrolizumab was considered the cause of hypophysitis. Pembrolizumab was discontinued and toxicity was managed with corticosteroids and hormonal replacement therapy (HRT). After 7 months of follow-up, symptoms were controlled with HRT but thyrotropin and corticotropin hormones had not recovered. It was decided not to reintroduce immunotherapy. Although endocrine disorders are common with the use of anti-PD-1, hypophysitis is very rare. However, clinical signs and symptoms can be nonspecific, therefore, it has probably been underdiagnosed. Monitoring hormones before and during the treatment is important for an early diagnosis and also to replace the alterations with HRT to control the symptoms. Hormonal function does not always recover, but it does not mean immunotherapy cannot be restarted and it should be evaluated in every case.

Current challenges of hematologic complications due to immune checkpoint blockade: a comprehensive review

Immune checkpoint blockade has demonstrated durable clinical benefits in a variety of malignancies. These immune checkpoint inhibitors (ICIs) produce unwanted autoimmune reactions due to an impaired self-tolerance. Hematologic immune-related adverse events (heme-irAEs) have been increasingly reported in the literature with a reported fatality rate of 12%. In this review, we illustrate 3 cases treated at Johns Hopkins Hospital for ICI-induced agranulocytosis, aplastic anemia, and thrombocytopenia. We then summarize the available evidence regarding the incidence and prevalence of heme-irAEs. We identified immune thrombocytopenia and hemolytic anemia as the most commonly reported heme-irAEs which are more commonly observed with nivolumab therapy. Median time to onset of heme-irAEs varies between patients but occurs earlier with CTLA-4 inhibitors than with anti-PD-L1/PD-1 agents. We also describe the current challenges regarding the recurrence of heme-irAEs despite immune checkpoint blockade termination. We provide the available evidence supporting a mixed T-cell and B-cell immune-mediated response. Finally, we review the treatment algorithm of these complications and provide treatment alternatives to steroid-refractory cases.

Preclinical characterization of dostarlimab, a therapeutic anti-PD-1 antibody with potent activity to enhance immune function in in vitro cellular assays and in vivo animal models

Inhibitors of programmed cell death protein 1 (PD-1) and its ligand (PD-L1) have dramatically changed the treatment landscape for patients with cancer. Clinical activity of anti-PD-(L)1 antibodies has resulted in increased median overall survival and durable responses in patients across selected tumor types. To date, 6 PD-1 and PD-L1, here collectively referred to as PD-(L)1, pathway inhibitors are approved by the US Food and Drug Administration for clinical use. The availability of multiple anti-PD-(L)1 antibodies provides treatment and dosing regimen choice for patients with cancer. Here, we describe the nonclinical characterization of dostarlimab (TSR-042), a humanized anti-PD-1 antibody, which binds with high affinity to human PD-1 and effectively inhibits its interaction with its ligands, PD-L1 and PD-L2. Dostarlimab enhanced effector T-cell functions, including cytokine production, in vitro. Since dostarlimab does not bind mouse PD-1, its single-agent antitumor activity was evaluated using humanized mouse models. In this model system, dostarlimab demonstrated antitumor activity as assessed by tumor growth inhibition, which was associated with increased infiltration of immune cells. Single-dose and 4-week repeat-dose toxicology studies in cynomolgus monkeys indicated that dostarlimab was well tolerated. In a clinical setting, based on data from the GARNET trial, dostarlimab (Jemperli) was approved for the treatment of adult patients with mismatch repair–deficient recurrent or advanced endometrial cancer that had progressed on or following prior treatment with a platinum-containing regimen. Taken together, these data demonstrate that dostarlimab is a potent anti-PD-1 receptor antagonist, with properties that support its continued clinical investigation in patients with cancer.

Pembrolizumab for the treatment of renal cell carcinoma

INTRODUCTION

The acquisition of resistance to VEGF-inhibiting therapies has prompted research toward immunotherapy for the treatment of metastatic renal cell carcinoma (mRCC). Among several, checkpoint inhibitors including PD-1 and PD-L1 inhibitors are the most promising approach.

AREAS COVERED

This review addresses the clinical efficacy of the anti-PD-1 monoclonal antibody pembrolizumab in first- and second-line treatment for mRCC regarding the most recent and significant published and ongoing studies. Attention is also given to its pharmacological characteristics as well as adverse events and its impact on patients' quality of life.

EXPERT OPINION

Immunotherapy has become the backbone for the treatment of advanced RCC. With the approval of several therapeutic options, research needs now to focus on defining the appropriate therapy for each patient. Axitinib plus pembrolizumab belongs to the combinations of tyrosine kinase inhibitors (TKI) plus immune checkpoint inhibitors for the first-line treatment of metastatic RCC. New combinations of pembrolizumab plus TKI for the evaluation in first- and second-line treatment of mRCC available. However, studies directly comparing the various treatment regimens using predictive biomarkers and long-term endpoints, including treatment-free survival, are lacking.

Immunotherapy for the treatment of metastatic small cell lung cancer: Focus on pembrolizumab

AREAS COVERED

The current evidence on the role of pembrolizumab for patients with extensive SCLC is reviewed in this article. Particularly, preclinical and clinical data from phase I/II and III clinical trials, which evaluate the efficacy and toxicity of pembrolizumab for these patients, are summarized based on PubMed/MEDLINE search and relevant articles. In addition, future perspectives on the emerging role of immunotherapy for SCLC are highlighted in light of potentially useful biomarkers.

EXPERT COMMENTARY

Pembrolizumab shows an excellent toxicity profile in recent studies, and significantly prolonged progression-free survival (PFS) but not overall survival (OS) in the phase III clinical trial KN604, in contrast to atezolizumab and durvalumab. The latter two agents have already been approved and incorporated in the daily clinical practice. Further research should be conducted so that phase III clinical trials can validate the potential clinical benefit of this checkpoint inhibitor in combination with other active agents and establish its role in the metastatic setting of SCLC.

Sequential Treatment with an Immune Checkpoint Inhibitor Followed by a Small-Molecule Targeted Agent Increases Drug-Induced Pneumonitis

PURPOSE

Immune checkpoint inhibitors (ICI) and targeted small-molecule drugs are mainstay elements of lung cancer chemotherapy. However, they are associated with development of pneumonitis, a rare, but potentially life-threatening event. We analyzed lung cancer patients treated with ICI to evaluate the effect of sequential therapeutic administration on the incidence of pneumonitis.

MATERIALS AND METHODS

In this retrospective study, 242 patients were included. Serial radiologic findings taken during and immediately after ICI treatment were reviewed. Factors that increased pneumonitis and the relationship between peri-ICI chemotherapy and the development of pneumonitis were evaluated.

RESULTS

Pneumonitis developed in 23 patients (9.5%); severe pneumonitis (grade ≥ 3) occurred in 13 of 23 patients (56%); pneumonitis-related death occurred in six. High-dose thoracic radiation (≥ 6,000 cGy) revealed a tendency toward high risk of pneumonitis (odds ratio, 2.642; 95% confidence interval, 0.932 to 7.490; p=0.068). Among 149 patients followed for ≥ 8 weeks after the final ICI dose, more patients who received targeted agents within 8-weeks post-ICI experienced pneumonitis (3/16, 18.8%) compared with patients who received cytotoxic agents (4/54, 7.4%) or no chemotherapy (4/79, 5.1%) (p=0.162). Targeted therapy was associated with earlier-onset pneumonitis than treatment with cytotoxic agents (35 vs. 62 days post-ICI, p=0.007); the resulting pneumonitis was more severe (grade ≥ 3, 100% vs. 0%, p=0.031).

CONCLUSION

Sequential administration of small-molecule targeted agents immediately after ICI may increase the risk of severe pneumonitis. The sequence of chemotherapy regimens that include ICI and targeted agents should be carefully planned to reduce the risk of pneumonitis in lung cancer patients.

Cardiovascular Complications of Prostate Cancer Treatment

Treatment of prostate cancer (PC) is a rapidly evolving field of pharmacology research. In recent years, numerous novel therapeutics that improve survival and ameliorate disease control have been approved. Currently, the systemic treatment for prostate neoplasm consists of hormonal therapy, chemotherapy, immunotherapy, radiopharmaceuticals, targeted therapy, and supportive agents (e.g., related to bone health). Unfortunately, many of them carry a risk of cardiovascular complications, which occasionally pose a higher mortality threat than cancer itself. This article provides a unique and comprehensive overview of the prevalence and possible mechanisms of cardiovascular toxicities of all PC therapies, including state-of-the-art antineoplastic agents. Additionally, this article summarizes available recommendations regarding screening and prevention of the most common cardiac complications among patients with advanced cancer disease.

Progress in Research on Tumor Metastasis Inhibitors

Tumor metastasis is a significant cause of malignant cancer-related death. Therefore, inhibiting tumor metastasis is an effective means of treating malignant tumors. Increasing our understanding of the molecular mechanisms that govern tumor metastasis can reveal new anti-cancer targets. This article will discuss the breakthroughs in this area and the corresponding recent developments in anti-cancer drug discovery.

Pembrolizumab for the treatment of Hodgkin Lymphoma

INTRODUCTION

Classic Hodgkin lymphoma (cHL) is a cancer of the immune system. Combination chemotherapy and radiation therapy result in high cure rate, nevertheless, up to a quarter of patients with advanced stage cHL may relapse. One mechanism of relapse is through immune evasion; cHL can avoid immune destruction by manipulating T cell regulatory protein programmed cell death-1 (PD-1) and programmed cell death ligands 1 (PD-L1) and 2 (PD-L2) interaction. Immune checkpoint inhibitors (CPIs), such as pembrolizumab are effective in relapsed/refractory (R/R) cHL.

AREAS COVERED

We reviewed prior and ongoing investigation of pembrolizumab use in R/R cHL, maintenance after autologous stem cell transplant (ASCT) and in frontline setting. Phase I study of pembrolizumab (KEYNOTE-013) demonstrated safety in R/R cHL with subsequent phase II study (KEYNOTE-087) confirmed efficacy signal. Intriguing early data support the use of maintenance pembrolizumab after ASCT in high-risk cHL patients. Second line and frontline studies incorporating CPIs have demonstrated promising efficacy with no significant additive toxicities.

EXPERT OPINION

Immune CPIs that block PD-1/PD-L1 and PD-L2 interaction are an effective strategy in R/R cHL. Pembrolizumab demonstrated safety and efficacy in the treatment of R/R cHL. The optimal utilization of pembrolizumab in frontline therapy is under investigation.

Current Treatment Options for HCC: From Pharmacokinetics to Efficacy and Adverse Events in Liver Cirrhosis

BACKGROUND

Hepatocellular carcinoma (HCC) is among the world's most common cancers. For over ten years, the only medical treatment for it has been the multikinase inhibitor Sorafenib. Currently, however, other first or second-line therapeutic options have also shown efficacy against HCC, such as multikinase inhibitors (Regorafenib, Lenvatinib, and Cabozantinib), a monoclonal antibody against the vascular endothelial growth factor receptor 2 (Ramucirumab), and immune-checkpoint inhibitors (Nivolumab, Pembrolizumab, Ipilimumab).

AIM

The aim of this paper is to review the metabolic pathways of drugs that have been tested for the treatment of HCC and the potential influence of liver failure over those pathways.

METHODS

The Food and Drug Administration (FDA)'s and European Medicines Agency (EMA)'s datasheets, results from clinical trials and observational studies have been reviewed.

RESULTS

This review summarizes the current knowledge regarding targets, metabolic pathways, drug interactions, and adverse events of medical treatments for HCC in cirrhotic patients.

CONCLUSION

The new scenario of systemic HCC therapy includes more active drugs with different metabolic pathways and different liver adverse events. Clinical and pharmacological studies providing more data on the safety of these molecules are urgently needed.

Immune Checkpoint Inhibitors in Melanoma: A Review of Pharmacokinetics and Exposure-Response Relationships

Immune checkpoint inhibitors are a new class of monoclonal antibodies that amplify T-cell-mediated immune responses against cancer cells. The introduction of these new drugs, first anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) and then anti-programmed death-1 (anti-PD1), was a major improvement in the treatment of advanced or metastatic melanoma, a highly immunogenic tumour. The development strategy for immune checkpoint immunotherapies differed from that traditionally used for cytotoxic therapies in oncology. The choices of doses at which to conduct clinical trials, and subsequently the choice of doses at which to use these new therapies, were not based on the identification of a maximum tolerated dose from dose-escalation studies; thus, pharmacokinetic and pharmacokinetic-pharmacodynamic modelling was essential. The studies conducted have shown that the pharmacokinetics of ipilimumab were linear and not time-dependent. In addition, there was a correlation between the trough concentrations of ipilimumab and its therapeutic efficacy. On the contrary, the anti-PD1 immunotherapies nivolumab and pembrolizumab had time-dependent pharmacokinetics. Their therapeutic efficacy was not related to their trough concentration, but there was a correlation between the clearance of anti-PD1 and the survival of melanoma patients. This review highlights the complexity of interpreting the exposure-response relationships of these agents. Further studies are needed to assess the value of therapeutic drug monitoring of immune checkpoint inhibitors in the treatment of melanoma.

Extended-Interval Dosing Strategy of Immune Checkpoint Inhibitors in Lung Cancer: Will it Outlast the COVID-19 Pandemic?

Patients with lung cancer are particularly vulnerable to complications from coronavirus disease-2019 (COVID-19). Recurrent hospital visits and hospital admission are potential risk factors for acquiring infection with its causative pathogen, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). As immune checkpoint inhibitors (ICIs) constitute the therapeutic backbone for the vast majority of patients with advanced lung cancer in the absence of actionable driver oncogenes, there have been intense discussions within the oncology community regarding risk-benefit of delaying these treatments or use of alternative extended-interval treatment strategies to minimize the risk of viral transmission secondary to unintended nosocomial exposures. In the midst of the COVID-19 pandemic, the U.S. Food and Drug Administration (FDA) granted accelerated approval for extended-interval strategy of pembrolizumab at a dose of 400 mg every 6 weeks for all already approved oncologic indications. Herein, we summarize the evidence from the in silico pharmacokinetic modeling/simulation studies supporting extended-interval dosing strategies for the ICIs used in lung cancer. We further review the evolving clinical evidence behind these approaches and predict that they will continue to be used in routine practice even long after the pandemic, particularly for patients with durable disease control.

Medical Gas Plasma Jet Technology Targets Murine Melanoma in an Immunogenic Fashion

Medical technologies from physics are imperative in the diagnosis and therapy of many types of diseases. In 2013, a novel cold physical plasma treatment concept was accredited for clinical therapy. This gas plasma jet technology generates large amounts of different reactive oxygen and nitrogen species (ROS). Using a melanoma model, gas plasma technology is tested as a novel anticancer agent. Plasma technology derived ROS diminish tumor growth in vitro and in vivo. Varying the feed gas mixture modifies the composition of ROS. Conditions rich in atomic oxygen correlate with killing activity and elevate intratumoral immune-infiltrates of CD8+ cytotoxic T-cells and dendritic cells. T-cells from secondary lymphoid organs of these mice stimulated with B16 melanoma cells ex vivo show higher activation levels as well. This correlates with immunogenic cancer cell death and higher calreticulin and heat-shock protein 90 expressions induced by gas plasma treatment in melanoma cells. To test the immunogenicity of gas plasma treated melanoma cells, 50% of mice vaccinated with these cells are protected from tumor growth compared to 1/6 and 5/6 mice negative control (mitomycin C) and positive control (mitoxantrone), respectively. Gas plasma jet technology is concluded to provide immunoprotection against malignant melanoma both in vitro and in vivo.

A critical evaluation of pembrolizumab in addition to lenalidomide and dexamethasone for the treatment of multiple myeloma

Introduction: Several modalities of immunotherapy have proved successful in multiple myeloma, including immunomodulatory agents, monoclonal antibodies directed to plasma cell surface antigens and chimeric antigen receptor T cells. The PD-1 pathway is implicated in the progression of multiple myeloma. Several properties of lenalidomide are potentially synergistic with PD-1/PD-L1 blockade.Areas covered: Preclinical data related to anti-PD-1/PD-L1 antibodies and the results of early clinical trials of pembrolizumab single-agent and in combination with lenalidomide and dexamethasone are discussed. Despite promising preliminary data, the pivotal phase III trial evaluating lenalidomide and dexamethasone in combination with pembrolizumab in patients with newly diagnosed multiple myeloma presented unexpected safety findings and was discontinued. Differences with previous results and the findings of other trials involving pomalidomide as an immunomodulatory agent or nivolumab as anti-PD-1 antibody are discussed.Expert opinion: Disappointing efficacy outcomes of the combination of checkpoint blockade antibodies and immunomodulating agents in multiple myeloma along with toxicity issues make the combination unattractive in comparison with available alternatives. It is essential to critically review preclinical and clinical datha to understand the pitfalls of lenalidomide with pembrolizumab and similar combinations in multiple myeloma to gain insight on the future role of anti-PD-1 agents in emerging therapeutic scenarios.

Pharmacokinetic/pharmacodynamic relationship of therapeutic monoclonal antibodies used in oncology: Part 2, immune checkpoint inhibitor antibodies

Immune checkpoint inhibitors are monoclonal antibodies (mAbs) directed against negative immunologic regulators that are used to restore the immune response against cancer. Approved drugs include anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4), anti-programmed cell death 1 (PD-1) and anti-programmed cell death-ligand 1 (PD-L1) antibodies exhibiting pharmacokinetic (PK) characteristics typical of mAbs. Most factors such as age, sex, ethnicity, tumour burden, performance status and immunogenicity, but not body weight, do not seem to affect drug clearance clinically. However, an exposure-response relation has been described for both the efficacy and toxicity of anti-CTLA-4 and anti-PD-1 agents. The change in clearance over time is associated with overall response at least for nivolumab and pembrolizumab. Few PK/pharmacodynamic (PD) data are available for anti-PD-L1 mAbs, but time-varying clearance has been described for these drugs, and the high immunogenicity rate observed with atezolizumab may affect PK parameters and should be further studied. These data suggest the need for additional PK/PD studies. In this review, we summarise studies of the PKs of immune checkpoint inhibitors, exploring possible interactions with PD considerations.

Immune checkpoint inhibitor related myasthenia gravis: single center experience and systematic review of the literature

BACKGROUND

Myasthenia gravis (MG) is a rare but life-threatening adverse event of immune checkpoint inhibitors (ICI). Given the limited evidence, data from a large cohort of patients is needed to aid in recognition and management of this fatal complication.

METHODS

We reviewed our institutional databases to identify patients who had cancer and MG in the setting of ICI. We systematically reviewed the literature through August 2018 to identify all similar reported patients. We collected data on clinical and diagnostic features, management, and outcomes of these cases.

RESULTS

Sixty-five patients were identified. Median age was 73 years; 42 (65%) were males, 31 (48%) had metastatic melanoma, and 13 (20%) had a preexisting MG before ICI initiation. Most patients received anti-PD-1 (82%). Sixty-three patients (97%) developed ICI-related MG (new onset or disease flare) after a median of 4 weeks (1 to 16 weeks) of ICI initiation. Twenty-four patients (37%) experienced concurrent myositis, and respiratory failure occurred in 29 (45%). ICI was discontinued in 61 patients (97%). Death was reported in 24 patients (38%); 15 (23%) due to MG complication. A better outcome was observed in patients who received intravenous immunoglobulin (IVIG) or plasmapheresis (PLEX) as first-line therapy than in those who received steroids alone (95% vs 63% improvement of MG symptoms, p = 0.011).

CONCLUSIONS

MG is a life-threatening adverse event of acute onset and rapid progression after ICI initiation. Early use of IVIG or PLEX, regardless of initial symptoms severity, may lead to better outcomes than steroids alone. Our data suggest the need to reassess the current recommendations for management of ICI-related MG until prospective longitudinal studies are conducted to establish the ideal management approach for these patients.

Pharmacogenetics of the systemic treatment in advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers. To date, most patients with HCC are diagnosed at an advanced tumor stage, excluding them from potentially curative therapies (i.e., resection, liver transplantation, percutaneous ablation). Treatments with palliative intent include chemoembolization and systemic therapy. Among systemic treatments, the small-molecule multikinase inhibitor sorafenib has been the only systemic treatment available for advanced HCC over 10 years. More recently, other small-molecule multikinase inhibitors (e.g., regorafenib, lenvatinib, cabozantinib) have been approved for HCC treatment. The promising immune checkpoint inhibitors (e.g., nivolumab, pembrolizumab) are still under investigation in Europe while in the US nivolumab has already been approved by FDA in sorafenib refractory or resistant patients. Other molecules, such as the selective CDK4/6inhibitors (e.g., palbociclib, ribociclib), are in earlier stages of clinical development, and the c-MET inhibitor tivantinib did not show positive results in a phase III study. However, even if the introduction of targeted agents has led to great advances in patient response and survival with an acceptable toxicity profile, a remarkable inter-individual heterogeneity in therapy outcome persists and constitutes a significant problem in disease management. Thus, the identification of biomarkers that predict which patients will benefit from a specific intervention could significantly affect decision-making and therapy planning. Germ-line variants have been suggested to play an important role in determining outcomes of HCC systemic therapy in terms of both toxicity and treatment efficacy. Particularly, a number of studies have focused on the role of genetic polymorphisms impacting the drug metabolic pathway and membrane translocation as well as the drug mechanism of action as predictive/prognostic markers of HCC treatment. The aim of this review is to summarize and critically discuss the pharmacogenetic literature evidences, with particular attention to sorafenib and regorafenib, which have been used longer than the others in HCC treatment.

Isolated neutropenia as a rare but serious adverse event secondary to immune checkpoint inhibition

BACKGROUND

Compared to conventional chemotherapy, Immune checkpoint inhibitors (ICI) are known to have a distinct toxicity profile commonly identified as immune-related adverse events (irAEs). These irAEs that are believed to be related to immune dysregulations triggered by ICI can be serious and lead to treatment interruptions and in severe cases, precipitate permanent discontinuation. Isolated neutropenia secondary to ICI has been rarely documented in the literature and needs further description. We report a case of pembrolizumab related severe isolated neutropenia in a patient with metastatic non-small cell lung cancer. We were also able to obtain serial blood and plasma-based biomarkers for this patient during treatment and during neutropenia to understand trends that may correlate with the irAE. In addition we summarize important findings from other studies reporting on ICI related neutropenia.

CASE PRESENTATION

A 74 years old Caucasian male treated with single-agent pembrolizumab for metastatic non-small cell lung cancer presented with fevers, chills, and an isolated neutrophil count (ANC) of 0 2 weeks after the fourth dose. In addition to antibiotics, due to the strong suspicion of this neutropenia being immune-mediated, he was started on 1 mg/kg of steroids and also received filgrastim to accelerate neutrophil recovery. Serial trends in C-reactive protein and certain other inflammatory cytokines demonstrated a corresponding rise at the time of neutropenia. Post recovery, his pembrolizumab was kept on hold. Eight weeks later he had a second episode of neutropenia which was again managed similar to the first episode. Despite permanent discontinuation of ICI after the first neutropenia, his disease showed an ongoing complete metabolic response on imaging. Our literature review reveals that hematological toxicities constitute < 1% irAEs with isolated neutropenia roughly accounting for one-fourth of the hematological irAEs. Based on the handful of ICI related neutropenia cases reported to date, we identified nivolumab to be the most common offender. The median number of ICI cycles administered before presenting with neutropenia was three, and the median time to recovery was approximately two weeks. All of these neutropenic episodes were ≥ grade 3 and led to permanent ICI discontinuation. Using immunosuppressive therapies in conjunction with granulocyte-colony stimulating factor was the most common strategy described to have favorable results.

CONCLUSION

Neutropenia as an isolated irAE secondary to ICI is rare but represents a severe toxicity that needs early recognition and can often result in treatment discontinuations. Careful monitoring of these patients with the prompt initiation of immunosuppressive and supportive measures to promote rapid recovery as well as prevent and treat infectious complications should be part of the management algorithms. Serial monitoring of blood and plasma-based biomarkers from more extensive studies may help in identifying patients at risk for irAEs and thus guide patient selection for ICI.

Association of Immunotherapy With Overall Survival in Elderly Patients With Melanoma

Importance

Melanoma treatment has been revolutionized with the development of immune-based therapies that offer durable clinical responses in a subset of patients. Clinical outcomes after treatment by immunotherapy can be influenced by the host's immune system. The immune system is modified with age by age-related immune dysfunction.

Objective

To evaluate if age influences clinical outcome and immune adverse events in patients treated by immunotherapy for metastatic melanoma.

Design, Setting, and Participants

This was a single-center cohort analysis in patients treated with immunotherapy for metastatic melanoma between January 2007 and February 2016, in the Lyon Sud Hospital, France. A total of 92 patients with metastatic melanoma treated with ipilimumab, nivolumab, or pembrolizumab were retrospectively analyzed.

Main Outcomes and Measures

Overall survival, progression-free survival, and immune-related adverse events were evaluated for each treatment line according to the patients' age.

Results

A total of 92 patients were eligible and included in this study for a total of 120 lines of treatment. Fifty-four patients were included in the cohort that was 65 years or younger (24 [44%] were female; mean [SD] age, 48.1 [12.5] years), and 38 patients were included in the cohort that was older than 65 years (12 [34%] were female; mean [SD] age, 74.8 [6.9] years). Mean follow-up duration starting at treatment initiation was 12.5 months. Patients older than 65 years treated with immunotherapy had a better mean progression-free survival (4.8 vs 3.4 months; P = .04) and overall survival (not reached vs 10.1 months; P = .009) than younger patients in univariate analysis, and after adjusting on prognosis covariates. This was particularly true with patients treated with anti-programmed cell death protein 1. Common immune-related adverse effects were similar in both cohorts.

Conclusions and Relevance

Age might be associated with a better clinical outcome after treatment with immunotherapy in the real-life setting. In our cohort, older patients did not have more immune-related adverse events. Further studies are warranted to confirm our results and describe the underlying mechanisms involved.

Clinical utility of pembrolizumab in the management of advanced solid tumors: an evidence-based review on the emerging new data

Pembrolizumab is a full-length human immunoglobulin G4 (IgG4) monoclonal antibody directed against the immune checkpoint PD-1 to remove its binding with PD-L1 and thus to restore an anti-tumor immune response of T cells. Pembrolizumab is one of the most advanced immune checkpoint inhibitors for cancer care. Apart from rare and serious adverse effects, its favorable tolerance profile enables to treat fragile patients who have often no other choice than best supportive care. The effective retained dose of pembrolizumab is a venous administration of 200 mg every 3 weeks until disease progression, intolerance or up to 24 months. Pembrolizumab has already proven its efficacy and thus obtained marketing authorization in so-called hot or hypermutated tumors or tumors expressing PD-L1 such as melanomas, non-small cell lung cancers, urothelial carcinomas, cervical cancer, etc. Pembrolizumab is also authorized in the United States in the treatment of mismatch repair-deficient tumors or with microsatellite instability. The current challenge is to expand its use in tumor types that are supposed to be less immunogenic, for example, by attempting to warm up the tumor microenvironment, or by combining pembrolizumab with other molecules. An acceptable toxicity profile of such combinations remains to explore. We review here the current indications of this drug, the main prognostic and predictive factors of its efficacy as well as the potential forthcoming indications.

Pembrolizumab for the treatment of gastric cancer

INTRODUCTION

Gastric cancer is one of a few gastrointestinal malignancies in which immunotherapy has shown meaningful activity. Pembrolizumab is the first and only immune checkpoint inhibitor to be FDA-approved in gastric cancer. Areas Covered: This review summarizes the current and emerging clinical evidence for immune checkpoint inhibitors in advanced and metastatic gastric cancer, with a focus on pembrolizumab. Expert Commentary: Pembrolizumab has shown impressive activity in the third-line treatment of locally advanced and metastatic gastric cancer. It is currently being studied as upfront therapy in combination with chemotherapy. The emerging understanding of the molecular alterations and tumor immune microenvironment as predictors of immunotherapy response in gastric cancer are discussed. The impact of gastric mucosal dysbiosis on gastric carcinogenesis and the modulation of immunotherapy response by the gut microbiome are also reviewed.

Pembrolizumab and its use in the treatment of recurrent or metastatic head and neck cancer

Until recently, palliative options for the treatment of platinum-refractory recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) have been cytotoxic chemotherapy and EGFR inhibitors. These agents offer limited efficacy with substantial toxicity. The development of novel immune checkpoint inhibitors has challenged the standard treatment. Pembrolizumab is a potent and highly selective humanized monoclonal antibody that blocks the interaction between PD-1, an immune checkpoint receptor and its ligands PD-L1 and -2. In August 2016, the US FDA approved the use of pembrolizumab in R/M HNSCC following disease progression on or after platinum-containing chemotherapy. This review highlights the pharmacology, therapeutic efficacy and tolerability data relevant to the use of pembrolizumab for the treatment of R/M HNSCC. Readers will gain greater insight into the HNSCC tumor microenvironment, available biomarkers, and learn about important clinical considerations associated with the use of pembrolizumab and similar immune checkpoint inhibitors.

Pembrolizumab for the treatment of bladder cancer

INTRODUCTION

Until recently, patients with locally advanced or metastatic urothelial carcinoma after progression on cisplatin-containing chemotherapy had limited systemic treatment options with no significant survival benefit and poor tolerability. Advances in the field of immunotherapy with the introduction of checkpoint inhibitors have led to paradigm shifts in the treatment of various malignancies. Areas covered: The current review will summarize the clinical evidence of checkpoint inhibitors in bladder cancer, with a focus on pembrolizumab. Expert commentary: Category 1 evidence indicates that the checkpoint inhibitor pembrolizumab improves overall survival in patients with locally advanced or metastatic urothelial carcinoma who progressed after or during cisplatin-containing therapy as compared to current standard of care chemotherapy. Phase 1 and 2 evidence also indicates that checkpoint inhibitors are active in first line in patients who are ineligible for cisplatin-containing chemotherapy.

New Strategies Using Antibody Combinations to Increase Cancer Treatment Effectiveness

Antibodies have proven their high value in antitumor therapy over the last two decades. They are currently being used as the first-choice to treat some of the most frequent metastatic cancers, like HER2⁺ breast cancers or colorectal cancers, currently treated with trastuzumab (Herceptin) and bevacizumab (Avastin), respectively. The impressive therapeutic success of antibodies inhibiting immune checkpoints has extended the use of therapeutic antibodies to previously unanticipated tumor types. These anti-immune checkpoint antibodies allowed the cure of patients devoid of other therapeutic options, through the recovery of the patient’s own immune response against the tumor. In this review, we describe how the antibody-based therapies will evolve, including the use of antibodies in combinations, their main characteristics, advantages, and how they could contribute to significantly increase the chances of success in cancer therapy. Indeed, novel combinations will consist of mixtures of antibodies against either different epitopes of the same molecule or different targets on the same tumor cell; bispecific or multispecific antibodies able of simultaneously binding tumor cells, immune cells or extracellular molecules; immunomodulatory antibodies; antibody-based molecules, including fusion proteins between a ligand or a receptor domain and the IgG Fab or Fc fragments; autologous or heterologous cells; and different formats of vaccines. Through complementary mechanisms of action, these combinations could contribute to elude the current limitations of a single antibody which recognizes only one particular epitope. These combinations may allow the simultaneous attack of the cancer cells by using the help of the own immune cells and exerting wider therapeutic effects, based on a more specific, fast, and robust response, trying to mimic the action of the immune system.