Neutropenia in Cynomolgus Monkeys With Anti-Drug Antibodies Associated With Administration of Afucosylated Humanized Monoclonal Antibodies.

Removal of the core fucose from the Fc region of humanized monoclonal antibodies (afucosylated antibodies) enhances their antibody-dependent cell cytotoxicity activities in killing cancer cells. Based on the authors' experience and literature, administrations of afucosylated antibodies have been associated with neutropenia in cynomolgus monkeys. However, in a recent general toxicology study conducted with an afucosylated antibody in cynomolgus monkeys, transient neutropenia was observed and correlated with the emergence of anti-drug antibodies (ADAs) in the affected animals. To further explore the relationship between neutropenia, afucosylated antibodies, and ADAs in cynomolgus monkeys, we performed an investigational retrospective meta-analysis of data from general toxicology studies conducted with Genentech's therapeutic antibodies administered to cynomolgus monkeys between 2005 and 2021. In this analysis, transient neutropenia strongly correlated with ADA-induced inflammation in cynomolgus monkeys administered afucosylated antibodies. This may reflect the simultaneous occurrence of two distinct processes of neutrophil elimination and utilization, thus overwhelming bone marrow reserve capacity leading to transient neutropenia. The integrated analysis of immunogenicity, and anatomic and clinical pathology results from these studies highlights the correlation of transient neutropenia in cynomolgus monkeys with ADA-related inflammation, potentially exacerbated by enhanced effector function of afucosylated antibodies.

The effect of aromatase inhibitors against possible testis toxicity in pembrolizumab treated rats.

Pembrolizumab is a monoclonal antibody. Anastrozole is an infertility inhibitor of aromatase. Resveratrol is an antioxidant polyphenol in the reproductive system. This study was planned to demonstrate the protective effects of anastrozole and resveratrol against pembrolizumab-induced reproductive damage. Forty-two Sprague-Dawley rats were used in the study. Groups: The control, Pembrolizumab (PEMB), PEMB + Anastrazol (ANAST), PEMB + Resveratrol (RES), RES, and ANAST groups. At the end of the experiment, rats were euthanased under anaesthesia. Tissue samples were taken from rats for biochemical, histological, and ELISA evaluations. Tissues were subjected to routine tissue follow-up for histological analysis. Biochemically, thiobarbituric acid reactive substance (TBARS), glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) levels were measured. Sperm motility, abnormal sperm rate, and epididymal sperm concentration were examined spermatologically. Serum testosterone and programmed cell death-1 (PD-1) levels were measured using the ELISA. TBARS levels were significantly increased and GSH, SOD, GPx, and CAT levels were mitigated in PEMB-treated rats. Histologically; Control, ANAST, and RES groups testis samples were observed with normal histological appearance. Histological damage was detected in seminiferous tubule structures in testicular tissue in the PEMB group. In treatment groups, this damage was decreased. In addition, PD-1 and testosterone levels were evaluated by the ELISA method. ANAST and RES have therapeutic effects against reproductive damage caused by PEMB.

A novel mouse strain optimized for chronic human antibody administration.

Therapeutic human IgG antibodies are routinely tested in mouse models of oncologic, infectious, and autoimmune diseases. However, assessing the efficacy and safety of long-term administration of these agents has been limited by endogenous anti-human IgG immune responses that act to clear human IgG from serum and relevant tissues, thereby reducing their efficacy and contributing to immune complex­mediated pathologies, confounding evaluation of potential toxicity. For this reason, human antibody treatment in mice is generally limited in duration and dosing, thus failing to recapitulate the potential clinical applications of these therapeutics. Here, we report the development of a mouse model that is tolerant of chronic human antibody administration. This model combines both a human IgG1 heavy chain knock-in and a full recapitulation of human Fc receptor (FcγR) expression, providing a unique platform for in vivo testing of human monoclonal antibodies with relevant receptors beyond the short term. Compared to controls, hIgG1 knock-in mice mount minimal anti-human IgG responses, allowing for the persistence of therapeutically active circulating human IgG even in the late stages of treatment in chronic models of immune thrombocytopenic purpura and metastatic melanoma.

Effect of ofatumumab on pregnancy, parturition, and lactation in cynomolgus monkeys.

Knowledge of the impacts of the anti-CD20 monoclonal antibody ofatumumab on the developing immune system is limited. This study examined the effects of intravenous ofatumumab on pregnancy, parturition, and lactation, and on pre- and postnatal survival and development in cynomolgus monkeys, an established model for developmental toxicity assessment. Pregnant cynomolgus monkeys (n = 42) were randomized to receive vehicle only (control group; n = 14), low-dose ofatumumab (n = 14), or high-dose ofatumumab (n = 14). Survival, clinical outcomes, and clinical pathology investigations were evaluated regularly until lactation day (maternal animals) and postnatal day 180±1 (infants). Anatomic pathology was investigated in euthanized infants and unscheduled terminations of maternal animals and infants. Ofatumumab treatment was not associated with maternal toxicity or embryotoxicity and had no effect on the growth and development of offspring. As expected, B-cell depletion occurred in maternal animals and their offspring, with a reduced humoral immune response in infants of mothers on high-dose ofatumumab. Both effects were reversible. In the high-dose group, perinatal deaths of 3 infants were attributed to infections, potentially secondary to pharmacologically induced immunosuppression. The no-observed adverse-effect level for initial/maintenance ofatumumab doses was 100/20 mg, and 10/3 mg/kg for pharmacological effects in infant animals, which are associated with exposures significantly higher than those following therapeutic doses in humans. In this study with cynomolgus monkeys, ofatumumab treatment was not associated with maternal toxicity or embryotoxicity and had no effect on the growth and development of offspring.

Corneal in vivo confocal microscopy to detect belantamab mafodotin-induced ocular toxicity early and adjust the dose accordingly: a case report.

BACKGROUND: New targeted antibody-drug conjugates (ADCs) against multiple myeloma are known to induce adverse effects that may lead to treatment discontinuation. Preclinical studies reported early severe ocular damage related to the use of belantamab mafodotin (belamaf), including ocular surface inflammation, severe dry eye, and a specific toxicity to the cornea, namely microcystic keratopathy. While belamaf-induced ocular changes have not been prospectively studied, a better understanding of mechanisms involved as well as kinetics may aid in anticipating dose adjustment rather than stopping the treatment once clinical ocular damage is too severe. CASE PRESENTATION: A 61-year-old woman scheduled for belamaf as a fifth-line treatment against multiple myeloma was prospectively included. Clinical examinations were performed before and every 3 weeks afterward, together with in vivo confocal microscopy (IVCM) of the cornea. Visual acuity, symptoms, slit-lamp examination, and ultrastructural changes of the cornea were recorded according to the received dose of belamaf. More precisely, kinetics, shape, density, and location of the toxic corneal lesions have been followed and analyzed using IVCM. Also, specific lesions at the sub-basal nerve plexus layer were detected and characterized for the first time. This advanced approach allowed a better understanding of the belamaf-induced toxicity, further balancing the dose to maintain good vision and eye health while continuing the treatment. CONCLUSIONS: Systematic ultrastructural analysis and follow-up of the corneal state during ADCs treatment for multiple myeloma may open new avenues in the therapeutic approach. Early preclinical detection of ocular damage may accurately contribute to finding the correct dose for each patient and not stopping the treatment due to severe ocular adverse effects.

Immune Checkpoint Inhibitor-Related Pulmonary Toxicity: A Comprehensive Review, Part II.

The development of immune checkpoint inhibitors (ICIs) has changed the treatment paradigm for cancer. The ICIs nivolumab, pembrolizumab, and cemiplimab target programmed cell death protein 1, and durvalumab, avelumab, and atezolizumab target programmed death ligand 1. Ipilimumab targets cytotoxic T lymphocyte-associated antigen-4. Used as monotherapy or in combination, they have shown remarkable efficacy in melanoma, lung cancer, and many other solid tumors, and indications continue to evolve. These checkpoint inhibitors are typically well tolerated; however, they may cause immune-mediated adverse effects, resulting in inflammation of any organ system. Pulmonary toxicity is vital to recognize, and it can be more challenging to diagnose in patients with lung cancer, given the nature of the disease course and treatment.

Pre-clinical study of IRDye800CW-nimotuzumab formulation, stability, pharmacokinetics, and safety.

BACKGROUND: Epidermal growth factor receptor (EGFR) is a target for cancer therapy as it is overexpressed in a wide variety of cancers. Therapeutic antibodies that bind EGFR are being evaluated in clinical trials as imaging agents for positron emission tomography and image-guided surgery. However, some of these antibodies have safety concerns such as infusion reactions, limiting their use in imaging applications. Nimotuzumab is a therapeutic monoclonal antibody that is specific for EGFR and has been used as a therapy in a number of countries. METHODS: Formulation of IRDye800CW-nimotuzumab for a clinical trial application was prepared. The physical, chemical, and pharmaceutical properties were tested to develop the specifications to determine stability of the product. The acute and delayed toxicities were tested and IRDye800CW-nimotuzumab was determined to be non-toxic. Non-compartmental pharmacokinetics analysis was used to determine the half-life of IRDye800CW-nimotuzumab. RESULTS: IRDye800CW-nimotuzumab was determined to be non-toxic from the acute and delayed toxicity study. The half-life of IRDye800CW-nimotuzumab was determined to be 38 ± 1.5 h. A bi-exponential analysis was also used which gave a t1/2 alpha of 1.5 h and t1/2 beta of 40.8 h. CONCLUSIONS: Here, we show preclinical studies demonstrating that nimotuzumab conjugated to IRDye800CW is safe and does not exhibit toxicities commonly associated with EGFR targeting antibodies.

Clinical and Histological Characterization of Toxic Keratopathy From Depatuxizumab Mafodotin (ABT-414), an Antibody-Drug Conjugate.

PURPOSE: To report the histological findings and clinical course of 2 patients with microcyst-like epithelial keratopathy (MEK) associated with antibody-drug conjugate, depatuxizumab mafodotin. METHODS: Case series. RESULTS: Two patients with glioblastoma multiforme participating in a phase 3 clinical trial of the antibody-drug conjugate, depatuxizumab mafodotin, presented with bilateral MEK. Confocal imaging showed multiple large, round, hyperreflective lesions in the epithelium. Epithelial debridement was performed for symptomatic relief in both patients. Along with aggressive lubrication, bandage contact lenses, and reduction in the chemotherapeutic dose to maintenance levels, both patients experienced symptomatic improvement. However, MEK lesions recurred after re-epithelialization. Immunohistochemistry of the diseased epithelium showed immunoglobulin (Ig)G-positive granular cytoplasmic inclusions and increased cell apoptosis. CONCLUSIONS: Depatuxizumab mafodotin accumulates in the basal corneal epithelium resulting in MEK because of increased apoptosis. Frequent lubrication and bandage contact lenses can provide symptom relief.

British Society of Gastroenterology endorsed guidance for the management of immune checkpoint inhibitor-induced enterocolitis.

Immune checkpoint inhibitors are a novel class of cancer treatment that have improved outcomes for a subset of cancer patients. They work by antagonising inhibitory immune pathways, thereby augmenting immune-mediated antitumour responses. However, immune activation is not cancer-specific and often results in the activation of immune cells in non-cancer tissues, resulting in off-target immune-mediated injury and organ dysfunction. Diarrhoea and gastrointestinal tract inflammation are common and sometimes serious side-effects of this type of therapy. Prompt recognition of gastrointestinal toxicity and, in many cases, rapid institution of anti-inflammatory or biologic therapy (or both) is required to reverse these complications. Management of organ-specific complications benefits from multidisciplinary input, including engagement with gastroenterologists for optimal management of immune checkpoint inhibitor-induced enterocolitis. In this British Society of Gastroenterology endorsed guidance document, we have developed a consensus framework for the investigation and management of immune checkpoint inhibitor-induced enterocolitis.

Phase IA/IB study of single-agent tislelizumab, an investigational anti-PD-1 antibody, in solid tumors.

BACKGROUND: The programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) axis plays a central role in suppressing antitumor immunity; axis dysregulation can be used by cancer cells to evade the immune system. Tislelizumab, an investigational monoclonal antibody with high affinity and binding specificity for PD-1, was engineered to minimize binding to FcγR on macrophages to limit antibody-dependent phagocytosis, a potential mechanism of resistance to anti-PD-1 therapy. The aim of this phase IA/IB study was to investigate the safety/tolerability, antitumor effects and optimal dose and schedule of tislelizumab in patients with advanced solid tumors. METHODS: Patients (aged ≥18 years) enrolled in phase IA received intravenous tislelizumab 0.5, 2, 5 or 10 mg/kg every 2 weeks; 2 or 5 mg/kg administered every 2 weeks or every 3 weeks; or 200 mg every 3 weeks; patients in phase IB received 5 mg/kg every 3 weeks. Primary objectives were to assess tislelizumab's safety/tolerability profile by adverse event (AE) monitoring and antitumor activity using RECIST V.1.1. PD-L1 expression was assessed retrospectively with the VENTANA PD-L1 (SP263) Assay. RESULTS: Between May 2015 and October 2017, 451 patients (n=116, IA; n=335, IB) were enrolled. Fatigue (28%), nausea (25%) and decreased appetite (20%) were the most commonly reported AEs. Most AEs were grade 1-2 severity; anemia (4.9%) was the most common grade 3-4 AE. Treatment-related AEs led to discontinuation in 5.3% of patients. Grade 5 AEs were reported in 14 patients; 2 were considered related to tislelizumab. Pneumonitis (2%) and colitis (1%) were the most common serious tislelizumab-related AEs. As of May 2019, 18% of patients achieved a confirmed objective response in phase IA and 12% in phase IB; median follow-up duration was 13.6 and 7.6 months, respectively. Pharmacokinetics, safety and antitumor activity obtained from both phase IA and IB determined the tislelizumab recommended dose; ultimately, tislelizumab 200 mg intravenous every 3 weeks was the dose and schedule recommended to be taken into subsequent clinical trials. CONCLUSIONS: Tislelizumab monotherapy demonstrated an acceptable safety/tolerability profile. Durable responses were observed in heavily pretreated patients with advanced solid tumors, supporting the evaluation of tislelizumab 200 mg every 3 weeks, as monotherapy and in combination therapy, for the treatment of solid tumors and hematological malignancies. TRIAL REGISTRATION NUMBER: NCT02407990.

A Potent Pan-TGFß Neutralizing Monoclonal Antibody Elicits Cardiovascular Toxicity in Mice and Cynomolgus Monkeys.

Transforming growth factor ß (TGFß) signaling has been recently shown to reduce antitumor response to PD-L1 blockade, leading to a renewed enthusiasm in developing anti-TGFß therapies for potential combination with cancer immunotherapy agents. Inhibition of TGFß signaling in nonclinical toxicology species is associated with serious adverse toxicities including cardiac valvulopathies and anemia. Previously, cardiovascular toxicities have been thought to be limited to small molecule inhibitors of TGFß receptor and not considered to be a liability associated with pan-TGFß neutralizing monoclonal antibodies (mAbs). Here, we report the toxicity findings associated with a potent pan-TGFß neutralizing mAb (pan-TGFß mAb; neutralizes TGFß1, 2, and 3) after 5 weekly intravenous doses of 10, 30, and 100 mg/kg, followed by a 4-week recovery period, in mice and cynomolgus monkeys. Mortality was observed due to acute bleeding and cardiovascular toxicity in mice at ≥ 30 mg/kg and prolonged menstruation in female monkeys at 100 mg/kg. Additional findings considered to be on-target exaggerated pharmacology included generalized bleeding and cardiovascular toxicity in mice and monkeys; histopathologic changes in the teeth, tongue, and skin in mice; and abnormal wound healing and microscopic pathology in the bone in monkeys. Importantly, our data indicate that the cardiovascular toxicities associated with the inhibition of TGFß signaling are not limited to small molecule inhibitors but are also observed following administration of a potent pan-TGFß inhibiting mAb.

Cardiotoxicity and pro-inflammatory effects of the immune checkpoint inhibitor Pembrolizumab associated to Trastuzumab.

BACKGROUND: The immunotherapy has revolutionized the world of oncology in the last decades with considerable advantages in terms of overall survival in cancer patients. The association of Pembrolizumab and Trastuzumab was recently proposed in clinical trials for the treatment of Trastuzumab-resistant advanced HER2-positive breast cancer. Although immunotherapies are frequently associated with a wide spectrum of immune-related adverse events, the cardiac toxicity has not been properly studied. PURPOSE: We studied, for the first time, the putative cardiotoxic and pro-inflammatory effects of Pembrolizumab associated to Trastuzumab. METHODS: Cell viability, intracellular calcium quantification and pro-inflammatory studies (analyses of the production of Interleukin 1ß, 6 and 8, the expression of NF-kB and Leukotriene B4) were performed in human fetal cardiomyocytes. Preclinical studies were also performed in C57BL6 mice by analyzing fibrosis and inflammation in heart tissues. RESULTS: The combination of Pembrolizumab and Trastuzumab leads to an increase of the intracellular calcium overload (of 3 times compared to untreated cells) and to a reduction of the cardiomyocytes viability (of 65 and 20-25%, compared to untreated and Pembrolizumab or Trastuzumab treated cells, respectively) indicating cardiotoxic effects. Notably, combination therapy increases the inflammation of cardiomyocytes by enhancing the expression of NF-kB and Interleukins. Moreover, in preclinical models, the association of Pembrolizumab and Trastuzumab increases the Interleukins expression of 40-50% compared to the single treatments; the expression of NF-kB and Leukotriene B4 was also increased. CONCLUSION: Pembrolizumab associated to Trastuzumab leads to strong cardiac pro-inflammatory effects mediated by overexpression of NF-kB and Leukotriene B4 related pathways.

Immune checkpoint blockade toxicity among patients with cancer presenting to the emergency department.

OBJECTIVES: We sought to estimate the prevalence of patients with cancer presenting to the emergency department (ED) who are undergoing treatment with immune checkpoint blockade (ICB) therapy; report their chief complaints; describe and estimate the prevalence of immune-related adverse events (IRAEs). METHODS: Four abstractors reviewed the medical records of patients with cancer treated with ICB who presented to an ED in Paris, France between January 2012 and June 2017. Chief complaints, underlying malignancy and ICB characteristics, and the final diagnoses according to the emergency physician were recorded. Abstractors noted if an emergency physician identified that a patient was receiving an ICB and if the emergency physician considered the possibility of an IRAE. The gold standard as to whether an IRAE was the cause was the patients' referring oncologist's opinion that the ED symptoms were attributed to ICB and IRAE according to post-ED medical records. Descriptive statistics were reported. RESULTS: Among the 409 patients treated with ICB at our institution, 139 presented to the ED. Chief complaints were fatigue (25.2%), fever (23%), vomiting (13.7%), diarrhoea (13.7%), dyspnoea (12.2%), abdominal pain (11.5%), confusion (8.6%) and headache (7.9%). Symptoms were due to IRAEs in 20 (14.4%) cases. The most frequent IRAEs were colitis (40%), endocrine toxicity (30%), hepatitis (25%) and pulmonary toxicity (5%). Patients with IRAEs compared with those without them more frequently had melanoma; had received more distinct courses of ICB treatment, an increased number of ICB medications and ICB cycles; and had a shorter time course since the last infusion of ICB. Emergency physicians considered the possibility of an IRAE in 24 (17.3%) of cases and diagnosed IRAE in 10 (50%) of those with later confirmed IRAE. IRAE was more likely to be missed when the referring oncologist was not contacted or when the patient had respiratory symptoms, fatigue or fever. CONCLUSIONS: ICB exposes patients to potentially severe IRAEs. Emergency physicians must identify patients treated with ICB and consider their toxicity when patients present to the ED with symptoms compatible with IRAEs.

Evaluation of a TGN1412 analogue using in vitro assays and two immune humanized mouse models.

Cytokine release syndrome (CRS) is a serious and potentially life-threatening complication typically associated with biological drug products. Pre-clinical testing in vitro and in vivo studies using non-human primates had failed to reliably predict CRS. To determine if bone marrow-thymus-liver (BLT) humanized mice with a fully engrafted human immune system or a CD34-humanized mouse model could predict CRS, we tested an anti-CD28 monoclonal antibody (mAb) similar to TGN1412. This TGN1412 analogue (TGN1412A) was initially tested in vitro and found to produce significant dose-dependent increases in cytokine production. For in vivo studies, adalimumab, an anti-tumor necrosis factor-alpha antibody known not to cause CRS, served as a negative control. We evaluated immune cell activation and cytokine expression in three independent experiments. In BLT humanized mice, significant increases in levels of human cytokines were identified in animals treated with anti-CD28 mAb. As expected, CD28+ cell detection was strongly reduced in the anti-CD28 treated group. Increased T cell activation was also observed. The control group did not show reductions in CD28+ T-cells and did not experience increased cytokine levels. Responses by CD34-humanized mice showed no significant differences between adalimumab and anti-CD28 treatment at doses used to test BLT-humanized mice. These results suggest that the TGN1412A produces similar results in vitro to the original TGN1412 monoclonal antibody. The BLT immune humanized mice but not the CD34 humanized mice produce both robust and specific cytokine responses and may represent a pre-clinical model to identify CRS.

SHR-A1403, a novel c-Met antibody-drug conjugate, exerts encouraging anti-tumor activity in c-Met-overexpressing models.

Emerging evidence demonstrates that a c-Met antibody-drug conjugate (ADC) has superior efficacy and safety profiles compared with those of currently available small molecules or antibody inhibitors for the treatment of c-Met-overexpressing cancers. Here we described both the in vitro and in vivo efficacies of SHR-A1403, a novel c-Met ADC composed of a humanized IgG2 monoclonal antibody against c-Met conjugated to a novel cytotoxic microtubule inhibitor. SHR-A1403 showed high affinity to c-Met proteins derived from human or monkey and potent inhibitory effects in cancer cell lines with high c-Met protein expression. In mice bearing tumors derived from cancer cell lines or patient HCC tissues with confirmed c-Met overexpression, SHR-A1403 showed excellent anti-tumor efficacy. Antibody binding with c-Met contributed to SHR-A1403 endocytosis; the subsequent translocation to lysosomes and cytotoxicity of the released toxin are speculated to be predominant mechanisms underlying the anti-tumor activity of SHR-A1403. In conclusion, SHR-A1403 showed significant anti-tumor activity in cancer cell lines, xenograft mouse models and an HCC PDX model, which all have high c-Met levels. These data provide references for SHR-A1403 as a potential therapy for the treatment of cancers with c-Met overexpression.

Organ-on-Chip Recapitulates Thrombosis Induced by an anti-CD154 Monoclonal Antibody: Translational Potential of Advanced Microengineered Systems.

Clinical development of Hu5c8, a monoclonal antibody against CD40L intended for treatment of autoimmune disorders, was terminated due to unexpected thrombotic complications. These life-threatening side effects were not discovered during preclinical testing due to the lack of predictive models. In the present study, we describe the development of a microengineered system lined by human endothelium perfused with human whole blood, a "Vessel-Chip." The Vessel-Chip allowed us to evaluate key parameters in thrombosis, such as endothelial activation, platelet adhesion, platelet aggregation, fibrin clot formation, and thrombin anti-thrombin complexes in the Chip-effluent in response to Hu5c8 in the presence of soluble CD40L. Importantly, the observed prothrombotic effects were not observed with Hu5c8-IgG2σ designed with an Fc domain that does not bind the FcγRIIa receptor, suggesting that this approach may have a low potential risk for thrombosis. Our results demonstrate the translational potential of Organs-on-Chips, as advanced microengineered systems to better predict human response.

Immune Checkpoint Inhibitors and Cardiac Toxicity: An Emerging Issue.

Although survival of patients with different types of cancer has improved, cardiotoxicity induced by anti-neoplastic drugs remains a critical issue. Cardiac dysfunction after treatment with anthracyclines has historically been a major problem. However, also targeted therapies and biological molecules can induce reversible and irreversible cardiac dysfunction. Over the last years, cancer immunotherapies haverevolutionized the clinical management of a wide spectrum of solid and hematopoietic malignancies previously endowed with poor prognosis. Immune checkpoint inhibitors are at the forefront of immunotherapy: the two most prominent are the targeting of cytotoxic-T-lymphocyte-associated antigen 4 (CTLA- 4) and of programmed cell death 1 (PD-1) and its ligand PD-L1. Ipilimumab (anti-CTLA-4) is the godfather of checkpoint inhibitors, whereas several blocking monoclonal antibodies targeting PD-1 (nivolumab and pembrolizumab) and PD-L1 (atezolizumab, durvalumab, avelumab, and BMS-946559) have been developed. Inhibitors of CTLA-4 and PD-1/PD-L1 pathway can unleash anti-tumor immunity and mediate cancer regressions. Although CTLA-4 inhibitors and PD-1 and PD-L1 blocking agents are frequently associated with a wide spectrum of immune-related adverse events, cardiac toxicity has been underestimated. However, early animal studies have demonstrated that after CTLA-4 inhibition and PD-1 deletion autoimmune myocarditis can occur. Moreover, PD-1 and PD-L1 can be expressed in rodent and human cardiomyocytes. During the last years several cases of fatal heart failure have been documented in melanoma patients treated with checkpoint inhibitors. The recent experience with cardiovascular toxic effects associated with checkpoint inhibitors introduces important concepts biologically and clinically relevant for future oncology trials and clinical practice.

Risk of sinusoidal obstruction syndrome in allogeneic stem cell transplantation after prior gemtuzumab ozogamicin treatment: a retrospective study from the Acute Leukemia Working Party of the EBMT.

Gemtuzumab ozogamicin (GO) may increase the risk of sinusoidal obstruction syndrome (SOS) when used prior to allogeneic stem cell transplantation (HSCT). We assessed SOS incidence and outcomes after HSCT of 146 adults, with a median age of 50 years, previously receiving GO. SOS prophylaxis was used in 69 patients (heparin n=57, ursodeoxycholic acid n=8, defibrotide n=4). Cumulative incidence (CI) of SOS was 8% (n=11), with death in 3 patients. Median interval between last GO dose and HSCT was 130 days. Overall survival (OS) and SOS incidence did not differ for patients receiving GO ⩽3.5 months before HSCT and the others. CI of acute and chronic GVHD was 31% and 25%, respectively. Probability of OS and leukemia-free survival (LFS) at 5 years was 40% and 37%, respectively. Relapse incidence and non-relapse mortality were 42% and 21%, respectively. In multivariate analysis, active disease at HSCT was associated with relapse and worse LFS and OS (P<0.03). Liver abnormalities before HSCT correlated with worse OS (P<0.03). Use of low-dose GO prior to HSCT is associated with an acceptable SOS incidence. Prospective studies investigating the role and the utility of SOS prophylaxis are warranted.

Nerve growth factor inhibition with tanezumab influences weight-bearing and subsequent cartilage damage in the rat medial meniscal tear model.

OBJECTIVE: To investigate whether the effects of nerve growth factor (NGF) inhibition with tanezumab on rats with medial meniscal tear (MMT) effectively model rapidly progressive osteoarthritis (RPOA) observed in clinical trials. METHODS: Male Lewis rats underwent MMT surgery and were treated weekly with tanezumab (0.1, 1 or 10 mg/kg), isotype control or vehicle for 7, 14 or 28 days. Gait deficiency was measured to assess weight-bearing on the operated limb. Joint damage was assessed via histopathology. A second arm, delayed onset of treatment (starting 3-8 weeks after MMT surgery) was used to control for analgesia early in the disease process. A third arm, mid-tibial amputation, evaluated the dependency of the model on weight-bearing. RESULTS: Gait deficiency in untreated rats was present 3-7 days after MMT surgery, with a return to normal weight-bearing by days 14-28. Prophylactic treatment with tanezumab prevented gait deficiency and resulted in more severe cartilage damage. When onset of treatment with tanezumab was delayed to 3-8 weeks after MMT surgery, there was no increase in cartilage damage. Mid-tibial amputation completely prevented cartilage damage in untreated MMT rats. CONCLUSIONS: These data suggest that analgesia due to NGF inhibition during the acute injury phase is responsible for increased voluntary weight-bearing and subsequent cartilage damage in the rat MMT model. This model failed to replicate the hypotrophic bone response observed in tanezumab-treated patients with RPOA.