A therapeutic strategy to target distinct sources of IgE and durably reverse allergy

Immunoglobulin E (IgE) is a key driver of type 1 hypersensitivity reactions and allergic disorders, which are globally increasing in number and severity. Although eliminating pathogenic IgE may be a powerful way to treat allergy, no therapeutic strategy reported to date can fully ablate IgE production. Interleukin-4 receptor α (IL-4Rα) signaling is required for IgE class switching, and IL-4Rα blockade gradually reduces, but does not eliminate, IgE. The persistence of IgE after IL-4Rα blockade may be due to long-lived IgE+ plasma cells that maintain serological memory to allergens and thus may be susceptible to plasma cell-targeted therapeutics. We demonstrate that transient administration of a B cell maturation antigen x CD3 (BCMAxCD3) bispecific antibody markedly depletes IgE, as well as other immunoglobulins, by ablating long-lived plasma cells, although IgE and other immunoglobulins rapidly rebound after treatment. Concomitant IL-4Rα blockade specifically and durably prevents the reemergence of IgE by blocking IgE class switching while allowing the restoration of other immunoglobulins. Moreover, this combination treatment prevented anaphylaxis in mice. Together with additional cynomolgus monkey and human data, our studies demonstrate that allergic memory is primarily maintained by both non-IgE+ memory B cells that require class switching and long-lived IgE+ plasma cells. Our combination approach to durably eliminate pathogenic IgE has potential to benefit allergy in humans while preserving antibody-mediated immunity.

Preclinical, randomized phase 1, and compassionate use evaluation of REGN4461, a leptin receptor agonist antibody for leptin deficiency

Deficiency in the adipose-derived hormone leptin or leptin receptor signaling causes class 3 obesity in individuals with genetic loss-of-function mutations in leptin or its receptor LEPR and metabolic and liver disease in individuals with hypoleptinemia secondary to lipoatrophy such as in individuals with generalized lipodystrophy. Therapies that restore leptin-LEPR signaling may resolve these metabolic sequelae. We developed a fully human monoclonal antibody (mAb), REGN4461 (mibavademab), that activates the human LEPR in the absence or presence of leptin. In obese leptin knockout mice, REGN4461 normalized body weight, food intake, blood glucose, and insulin sensitivity. In a mouse model of generalized lipodystrophy, REGN4461 alleviated hyperphagia, hyperglycemia, insulin resistance, dyslipidemia, and hepatic steatosis. In a phase 1, randomized, double-blind, placebo-controlled two-part study, REGN4461 was well tolerated with an acceptable safety profile. Treatment of individuals with overweight or obesity with REGN4461 decreased body weight over 12 weeks in those with low circulating leptin concentrations (<8 ng/ml) but had no effect on body weight in individuals with higher baseline leptin. Furthermore, compassionate-use treatment of a single patient with atypical partial lipodystrophy and a history of undetectable leptin concentrations associated with neutralizing antibodies to metreleptin was associated with noteable improvements in circulating triglycerides and hepatic steatosis. Collectively, these translational data unveil an agonist LEPR mAb that may provide clinical benefit in disorders associated with relatively low leptin concentrations.

Patient management after primary rectal cancer diagnosis. Special focus on surgical treatment for non-metastatic disease

Background: Rectal cancer is a public health priority. Primary objectives of this study were to evaluate the quality of care for non-metastatic rectal cancer using process and outcome indicators. Delay of management, length of stay and readmission rate, sphincter preservation, morbidity, number of examined lymph nodes, mortality, overall and disease-free survivals were evaluated. Secondary objectives were to estimate the relationship between possible predictive parameters for (1) anastomotic leakage (logistic regression), (2) overall or disease-free survivals (cox regression).Methods: We performed a retrospective study on 312 consecutive patients diagnosed with primary rectal cancer between 2016 and 2019. We focused on the 163 patients treated by surgery for non-metastatic cancer.Results: The treatment began within 33 days (range 0-264) after incidence, resection rate was 67%. Digestive continuity rate in lower, middle and upper rectum was 30%, 87% and 96%. Median of 14 lymph nodes (range 1-46) was analyzed. Length of stay and readmission rate were 11 days (range 3-56) and 4%, respectively. Within 90 postoperative days, clinical anastomotic leakage occurred in 9.2% of cases, major morbidity rate was 17%, mortality 1.2%. Multivariate analysis revealed that stoma decreased the risk of anastomotic leakage [hazard ratio: 0.16; 95% confidence intervals: 0.04-0.63; p = 0.008]. The 5-year overall survival after surgery was 85 ± 4%, disease-free survival 83 ± 4%. Patients with major complications, male gender and R1/R2 resection margin had a poorer prognosis.Conclusion: This work showed encouraging results in rectal cancer treatment in our institution, our results were in line with recommendations at the time.

CD22-targeted CD28 bispecific antibody enhances antitumor efficacy of odronextamab in refractory diffuse large B cell lymphoma models

Although many patients with diffuse large B cell lymphoma (DLBCL) may achieve a complete response to frontline chemoimmunotherapy, patients with relapsed/refractory disease typically have poor outcomes. Odronextamab, a CD20xCD3 bispecific antibody that provides “signal 1” through the activation of the T cell receptor/CD3 complex, has exhibited early, promising activity for patients with highly refractory DLBCL in phase 1 trials. However, not all patients achieve complete responses, and many relapse, thus representing a high unmet medical need. Here, we investigated whether adding a costimulatory “signal 2” by engaging CD28 receptors on T cells could augment odronextamab activity. We demonstrate that REGN5837, a bispecific antibody that cross-links CD22-expressing tumor cells with CD28-expressing T cells, enhances odronextamab by potentiating T cell activation and cytolytic function. In preclinical DLBCL studies using human immune system–reconstituted animals, REGN5837 promotes the antitumor activity of odronextamab and induces intratumoral expansion of reprogrammable T cells while skewing away from a dysfunctional state. Although REGN5837 monotherapy shows limited activity and no toxicity in primate studies, it augments T cell activation when dosed in combination with odronextamab. In addition, analysis of non-Hodgkin lymphoma clinical samples reveals an increase in CD28 + CD8 + T cells after odronextamab treatment, demonstrating the presence of a population that could potentially be targeted by REGN5837. Collectively, our data demonstrate that REGN5837 can markedly enhance the antitumor activity of odronextamab in preclinical NHL models, and the combination of these two bispecific antibodies may provide a chemotherapy-free approach for the treatment of DLBCL.

A class of costimulatory CD28-bispecific antibodies that enhance the antitumor activity of CD3-bispecific antibodies

T cell activation is initiated upon binding of the T cell receptor (TCR)/CD3 complex to peptide-major histocompatibility complexes ("signal 1"); activation is enhanced by engagement of a second "costimulatory" receptor, such as the CD28 receptor on T cells binding to its cognate ligand(s) on the target cell ("signal 2"). CD3-based bispecific antibodies act by replacing conventional signal 1, linking T cells to tumor cells by binding a tumor-specific antigen (TSA) with one arm of the bispecific and bridging to TCR/CD3 with the other. Although some of these so-called TSAxCD3 bispecifics have demonstrated promising antitumor efficacy in patients with cancer, their activity remains to be optimized. Here, we introduce a class of bispecific antibodies that mimic signal 2 by bridging TSA to the costimulatory CD28 receptor on T cells. We term these TSAxCD28 bispecifics and describe two such bispecific antibodies: one specific for ovarian and the other for prostate cancer antigens. Unlike CD28 superagonists, which broadly activate T cells and resulted in profound toxicity in early clinical trials, these TSAxCD28 bispecifics show limited activity and no toxicity when used alone in genetically humanized immunocompetent mouse models or in primates. However, when combined with TSAxCD3 bispecifics, they enhance the artificial synapse between a T cell and its target cell, potentiate T cell activation, and markedly improve antitumor activity of CD3 bispecifics in a variety of xenogeneic and syngeneic tumor models. Combining this class of CD28-costimulatory bispecific antibodies with the emerging class of TSAxCD3 bispecifics may provide well-tolerated, off-the-shelf antibody therapies with robust antitumor efficacy.

Vertebral compression fracture during stereotactic body radiotherapy for spinal metastasis: A rare case of tracking failure

Spinal metastasis are a daily challenge in clinical practice. Stereotactic body radiotherapy (SBRT) allows delivery of definitive treatment with excellent long-term control rates. Its implementation needs dedicated devices and day-to-day image-guided radiotherapy (IGRT). The XSight™ spine tracking system, integrates with the CyberKnife® (Accuray™), provides a fiducial-free tracking system for spinal SBRT. We report a rare case of tracking failure during treatment due to the occurrence of a vertebral compression fracture (VCF).

A Mucin 16 bispecific T cell–engaging antibody for the treatment of ovarian cancer

Advanced ovarian cancer is frequently treated with combination chemotherapy, but high recurrence rates show the need for therapies that can produce durable responses and extend overall survival. Bispecific antibodies that interact with tumor antigens on cancer cells and activating receptors on immune cells offer an innovative immunotherapy approach. Here, we describe a human bispecific antibody (REGN4018) that binds both Mucin 16 (MUC16), a glycoprotein that is highly expressed on ovarian cancer cells, and CD3, thus bridging MUC16-expressing cells with CD3+ T cells. REGN4018 induced T cell activation and killing of MUC16-expressing tumor cells in vitro. Binding and cytotoxicity of REGN4018 in vitro were minimally affected by high concentrations of CA-125, the shed form of MUC16, which is present in patients. In preclinical studies with human ovarian cancer cells and human T cells in immunodeficient mice, REGN4018 potently inhibited growth of intraperitoneal ovarian tumors. Moreover, in a genetically engineered immunocompetent mouse expressing human CD3 and human MUC16 [humanized target (HuT) mice], REGN4018 inhibited growth of murine tumors expressing human MUC16, and combination with an anti–PD-1 antibody enhanced this efficacy. Immuno-PET imaging demonstrated localization of REGN4018 in MUC16-expressing tumors and in T cell–rich organs such as the spleen and lymph nodes. Toxicology studies in cynomolgus monkeys showed minimal and transient increases in serum cytokines and C-reactive protein after REGN4018 administration, with no overt toxicity. Collectively, these data demonstrate potent antitumor activity and good tolerability of REGN4018, supporting clinical evaluation of REGN4018 in patients with MUC16-expressing advanced ovarian cancer.

Abstract 1777: REGN4018, a novel MUC16xCD3 bispecific T-cell engager for the treatment of ovarian cancer

Advanced ovarian cancer has a high rate of recurrence, thus there is a need for therapies that can produce durable responses and extend overall survival. Infiltrating CD3+ T cells are reported to correlate with improved clinical outcome in stage III/IV ovarian cancer. Bispecific antibodies that engage T cells via CD3 and a tumor antigen on ovarian tumor cells may be able to exploit these tumor-infiltrating T cells and have drawn interest as a novel strategy of antitumor immunotherapy.

Mucin16 (MUC16) is a well described antigen highly expressed in ovarian cancer and several other tumors. We generated a human bispecific antibody (REGN4018) that binds MUC16 on tumor cells and CD3, bridging MUC16-expressing cells with CD3+ T cells. REGN4018 demonstrates MUC16-directed T cell activation and polyclonal T cell killing of MUC16-expressing tumor cells in vitro and in vivo. Binding and cytotoxicity are minimally affected by high concentrations of CA-125, the shed form of MUC16 that is used as a biomarker for ovarian cancer.

Several murine tumor models were developed to determine the in vivo anti-tumor effects of REGN4018. As a xenogenic tumor model, human OVCAR-3 cells were grown as ascites in immunodeficient mice [NOD-SCID-IL2Rgamma deficient (NSG)] pre-implanted with human PBMC. Significant tumor inhibition by REGN4018 was observed at doses of ≥ 0.1 mg/kg. To enable investigation of clinical bispecific antibodies in tumor-bearing immune competent mice, mice were genetically engineered to humanize both CD3 and a part of MUC16 covering the antibody binding region. ImmunoPET imaging demonstrated localization of REGN4018 in both T cell-rich organs such as the spleen and lymph nodes as well as in MUC16-expressing tumors. REGN4018 inhibited growth of murine tumors transfected with human MUC16 in syngeneic tumor models at doses ≥ 0.05 mg/kg.

The safety and tolerability of REGN4018 were evaluated in cynomolgous monkey studies. REGN4018 administration resulted in a minimal and transient increase in serum cytokines and C-reactive protein with no overt toxicity. Collectively, these data show the potent anti-tumor activity and tolerability of REGN4018 and provide strong support for the clinical testing of REGN4018 in patients with MUC16-expressing ovarian cancers.

Citation Format: Alison Crawford, Lauric Haber, Kristin Vazzana, Lauren Canova, Priyanka Ram, Jennifer Principio, Arpita Pawashe, Curtis Colleton, Marcus Kelly, Sosina Makkonen, Carlos Hickey, Paurene Duramad, Stephen Godin, John Lin, Eric Smith, Gavin Thurston, Jessica R. Kirshner. REGN4018, a novel MUC16xCD3 bispecific T-cell engager for the treatment of ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1777.

Population level analysis of evolved mutations underlying improvements in plant hemicellulose and cellulose fermentation by Clostridium phytofermentans

Background

The complexity of plant cell walls creates many challenges for microbial decomposition. Clostridium phytofermentans, an anaerobic bacterium isolated from forest soil, directly breaks down and utilizes many plant cell wall carbohydrates. The objective of this research is to understand constraints on rates of plant decomposition by Clostridium phytofermentans and identify molecular mechanisms that may overcome these limitations.

Results

Experimental evolution via repeated serial transfers during exponential growth was used to select for C. phytofermentans genotypes that grow more rapidly on cellobiose, cellulose and xylan. To identify the underlying mutations an average of 13,600,000 paired-end reads were generated per population resulting in ∼300 fold coverage of each site in the genome. Mutations with allele frequencies of 5% or greater could be identified with statistical confidence. Many mutations are in carbohydrate-related genes including the promoter regions of glycoside hydrolases and amino acid substitutions in ABC transport proteins involved in carbohydrate uptake, signal transduction sensors that detect specific carbohydrates, proteins that affect the export of extracellular enzymes, and regulators of unknown specificity. Structural modeling of the ABC transporter complex proteins suggests that mutations in these genes may alter the recognition of carbohydrates by substrate-binding proteins and communication between the intercellular face of the transmembrane and the ATPase binding proteins.

Conclusions

Experimental evolution was effective in identifying molecular constraints on the rate of hemicellulose and cellulose fermentation and selected for putative gain of function mutations that do not typically appear in traditional molecular genetic screens. The results reveal new strategies for evolving and engineering microorganisms for faster growth on plant carbohydrates.

The Shu complex interacts with Rad51 through the Rad51 paralogues Rad55-Rad57 to mediate error-free recombination

The Saccharomyces cerevisiae Shu complex, consisting of Shu1, Shu2, Csm2 and Psy3, promotes error-free homologous recombination (HR) by an unknown mechanism. Recent structural analysis of two Shu proteins, Csm2 and Psy3, has revealed that these proteins are Rad51 paralogues and mediate DNA binding of this complex. We show in vitro that the Csm2–Psy3 heterodimer preferentially binds synthetic forked DNA or 3′-DNA overhang substrates resembling structures used during HR in vivo. We find that Csm2 interacts with Rad51 and the Rad51 paralogues, the Rad55–Rad57 heterodimer and that the Shu complex functions in the same epistasis group as Rad55–Rad57. Importantly, Csm2’s interaction with Rad51 is dependent on Rad55, whereas Csm2’s interaction with Rad55 occurs independently of Rad51. Consistent with the Shu complex containing Rad51 paralogues, the methyl methanesulphonate sensitivity of Csm2 is exacerbated at colder temperatures. Furthermore, Csm2 and Psy3 are needed for efficient recruitment of Rad55 to DNA repair foci after DNA damage. Finally, we observe that the Shu complex preferentially promotes Rad51-dependent homologous recombination over Rad51-independent repair. Our data suggest a model in which Csm2–Psy3 recruit the Shu complex to HR substrates, where it interacts with Rad51 through Rad55–Rad57 to stimulate Rad51 filament assembly and stability, promoting error-free repair.

[Ocular redness in general medicine]

Ocular redness is analysed within the framework of the practice in general medicine. The stress of this work is laid on the development of clinical and anamnestic criteria (pain and diminution of visual acuity) which allow to suspect a serious pathology of the eye. The systematic examination of each entity is described under field conditions, using a simple light and fluorescein. The attitude of the general practitioner is detailed according to the degree of severity of the affection, while insisting on the clinical situations to refer to a specialist.

Ozone differential absorption lidar algorithm intercomparison

An intercomparison of ozone differential absorption lidar algorithms was performed in 1996 within the framework of the Network for the Detection of Stratospheric Changes (NDSC) lidar working group. The objective of this research was mainly to test the differentiating techniques used by the various lidar teams involved in the NDSC for the calculation of the ozone number density from the lidar signals. The exercise consisted of processing synthetic lidar signals computed from simple Rayleigh scattering and three initial ozone profiles. Two of these profiles contained perturbations in the low and the high stratosphere to test the vertical resolution of the various algorithms. For the unperturbed profiles the results of the simulations show the correct behavior of the lidar processing methods in the low and the middle stratosphere with biases of less than 1% with respect to the initial profile to as high as 30 km in most cases. In the upper stratosphere, significant biases reaching 10% at 45 km for most of the algorithms are obtained. This bias is due to the decrease in the signal-to-noise ratio with altitude, which makes it necessary to increase the number of points of the derivative low-pass filter used for data processing. As a consequence the response of the various retrieval algorithms to perturbations in the ozone profile is much better in the lower stratosphere than in the higher range. These results show the necessity of limiting the vertical smoothing in the ozone lidar retrieval algorithm and questions the ability of current lidar systems to detect long-term ozone trends above 40 km. Otherwise the simulations show in general a correct estimation of the ozone profile random error and, as shown by the tests involving the perturbed ozone profiles, some inconsistency in the estimation of the vertical resolution among the lidar teams involved in this experiment.

Project LEAP of New Jersey: lower extremity amputation prevention in persons with type 2 diabetes

OBJECTIVE

To reduce type 2 diabetes-related lower extremity amputations (LEAs) in New Jersey through a statewide training program for primary care providers at healthcare agencies in high-risk areas.

STUDY DESIGN

Project LEAP provided 27 1-day training workshops to 560 healthcare professionals representing 85 organizations. The effect of training was evaluated based on a multiple-choice knowledge test, self-reported practice behaviors, and a medical records audit of practice behaviors, and pre- and postprogram LEA rates.

PATIENTS AND METHODS

We evaluated statistically significant differences in pre- and postprogram knowledge scores using Student's t-tests. We also evaluated providers' intentions to change clinical foot-care practices and compared them with actual practices documented in medical records. We used analysis of variance to determine any statistically significant differences in pre- and postprogram LEA rates at various types of institutions. In addition, we assisted facilities in the development of self-education programs containing specific foot-care modules.

RESULTS

Participating providers were: 70.6% nurses, 7.8% physicians, 4.5% podiatrists, 4.2% dietitians, and 12.9% all others. Pre- and postprogram knowledge scores increased by 12% (T = 13.29; P < 0.0001) and were maintained for 9 months (T = 7.58; P < 0.05). Provider intentions to change clinical practice behaviors correlated with self-reported practice changes 9 months postprogram (r = .51; P < 0.001). Medical record audits 1 year before and 9 months after training demonstrated marked improvement in foot-care practices in the following areas: (1) foot-care education given to patients by primary care providers; 2) documentation of peripheral vascular disease; 3) documentation of patient preventive care practices; and 4) referrals to diabetes educators, orthopedists, podiatrists, and diabetologists. Education programs with specific foot-care components increased 10%. The overall incidence of pre- and posttraining LEAs did not change significantly but differed depending on institution type. Hospitals and community healthcare centers were more likely to show postprogram reductions in LEAs than nursing homes and rehabilitation centers.

CONCLUSION

Institutionalization of a LEAP program resulted in improved provider knowledge and certain clinical practice behaviors. There was a trend toward an overall reduction in the number of LEAs at participating institutions.

Effect of lenograstim on the cost of autologous bone marrow transplantation. A preliminary communication

High dose chemotherapy and autologous bone marrow transplantation (BMT) can produce prolonged remission in patients with malignant lymphoma or solid tumours. However, neutropenia is a serious complication of treatment in patients with these diseases. In this study, we investigated the costs and effects of using lenograstim, a recombinant human granulocyte colony-stimulating factor, to treat neutropenia in 16 patients with lymphoma or solid tumours. The cost of lenograstim was not included in the calculations. The duration of neutropenia and hospitalisation were both lower in patients who received lenograstim compared with no treatment. The mean cost of autologous BMT was FF142,000 in patients who received lenograstim, compared with FF166,000 in patients who did not. Savings were largely attributable to decreased expenditure on hospitalisation in the lenograstim-treated group. The cost of 14 days' treatment with lenograstim was estimated at FF10,500, based on a daily dosage of 150 micrograms/m2/day.

[Influence of the granulocyte growth factor on the cost of bone marrow autografts in oncologic hematology]

OBJECTIVE

It is now possible to achieve prolonged remission of malignant lymphoma and certain cancers with high-dose chemotherapy followed by autograft with haematopoietic stem cells. We tested such a protocol, evaluating haematologic recovery, in order to determine the total cost of hospitalization.

METHODS

Sixteen patients were included in the study, 7 had severe or relapsing lymphoma, 7 had breast cancer or cancer of the ovary and 2 had cancer of the testicule. Mean age was 34 years, 14 patients reached complete remission and relapse occurred in 2. Ten patients were given granulocyte growth factor and 6 were given a placebo.

RESULTS

The duration of aplasia (number of days with a white cell count below 1 x 10(9)1) ranged from 10 to 32 days. In patients treated with granulocyte growth factor, it was shorter (16 vs 22 days) as was hospitalization time (27 vs 33 days). The cost of the autograft ranged from 100,000 FF to 250,000 FF and the average cost for the 16 patients was 149,500 FF including: 83,600 FF (56.4%) for hospitalization itself, 33,200 FF (22%) for drugs, mostly antibiotics, and 19,000 FF (13%) for laboratory examinations and 14,000 FF (9%) for blood transfusions. Total cost was lower in patients given granulocyte growth factor, 142,000 FF vs 166,000 FF for those given placebo.

CONCLUSION

In order to shorten the duration of the aplasia period, haematopoietic growth factors are widely used in autograft protocols. Our findings give an evaluation of the cost in 16 patients and show that cost decreases in patients given granulocyte growth factor. This reduction is cost is related to a lower hospitalization cost and not a reduction in the number of drugs and transfusions required.