The use of T-cell engagers (TCEs) to treat solid tumors is challenging, and several have been limited by narrow therapeutic windows due to substantial on-target, off-tumor toxicities due to the expression of low levels of target antigens on healthy tissues. Here, we describe TNB-928B, a fully human TCE that has a bivalent binding arm for folate receptor alpha (FRα) to selectively target FRα overexpressing tumor cells while avoiding the lysis of cells with low levels of FRα expression. The bivalent design of the FRα binding arm confers tumor selectivity due to low-affinity but high-avidity binding to high FRα antigen density cells. TNB-928B induces preferential effector T-cell activation, proliferation, and selective cytotoxic activity on high FRα expressing cells while sparing low FRα expressing cells. In addition, TNB-928B induces minimal cytokine release compared to a positive control TCE containing OKT3. Moreover, TNB-928B exhibits substantial ex vivo tumor cell lysis using endogenous T-cells and robust tumor clearance in vivo, promoting T-cell infiltration and antitumor activity in mouse models of ovarian cancer. TNB-928B exhibits pharmacokinetics similar to conventional antibodies, which are projected to enable favorable administration in humans. TNB-928B is a novel TCE with enhanced safety and specificity for the treatment of ovarian cancer.
8034 Background: T-cell redirecting therapies such as CAR-T cells and T-cell engaging bispecific antibodies (T-BsAb) targeting B Cell Maturation Antigen (BCMA) have been highly efficacious against relapsed/refractory myeloma (MM) in early phase clinical studies. However, strongly pan-T cell activating T-BsAbs have also been shown to overstimulate T cells, inducing toxicity and possibly decreasing efficacy. We have developed TNB-383B, a fully human BCMA-specific T-BsAb incorporating a low-activating αCD3 that preferentially activates effector over regulatory T cells. TNB-383B mediates T-cell killing of MM in vitro, ex vivo and in vivo but stimulates minimal cytokine release. Methods: In vitro and ex vivo efficacy studies included T-cell activation by cytokine- and tumor cell kill by calcein-release assays and/or flow cytometry. In vivo efficacy of the molecules was evaluated in NSG mice harboring myeloma cells and human PBMCs. Pharmacokinetics and tolerability were assessed in Cynomolgus. Results: TNB-383B showed T-cell activation and tumor-cell cytotoxicity in vitro and ex vivo, with markedly reduced cytokine production even at doses that showed maximum tumor cell lysis as compared to a positive control T-BsAb. In vivo, TNB-383B reduced tumor load and increased survival. TNB-383B had a T1/2 of ~13-16 days in Cyno, consistent with an IgG4 Ab. Conclusions: Our results suggest that TNB-383B may have a favorable toxicity profile with comparable or possibly improved efficacy compared to T-BsAbs that incorporate strong, pan T-cell activating anti-CD3 moieties in the treatment of MM.
The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study showed that treatment with the angiotensin II type-1 receptor antagonist losartan reduces overall stroke risk compared with conventional therapy with the beta-blocker atenolol. We conducted secondary analyses in LIFE to determine the extent to which the cerebrovascular benefits of losartan apply to different clinical subgroups and stroke subtypes and to assess the dependence of these benefits on baseline and time-varying covariates. Among 9193 hypertensive patients with electrocardiographic evidence of left ventricular hypertrophy, random allocation to losartan-based treatment lowered the risk of fatal (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.43 to 0.96; P=0.032) and atherothrombotic stroke (HR, 0.72; 95% CI, 0.59 to 0.88; P=0.001) compared with atenolol-based therapy. Although comparable risk reductions occurred for hemorrhagic and embolic stroke, these were not statistically significant. The number of neurological deficits per stroke was similar, but there were fewer strokes in the losartan group for nearly every level of stroke severity. Effects were consistent in all clinical subgroups except for those defined by age and ethnicity. The benefits of losartan on all strokes were independent of baseline and time-varying risk factors, including blood pressure. The number needed to treat for 5 years to prevent 1 stroke was 54 for the average participant, declining to 25, 24, and 9 for patients with cerebrovascular disease, isolated systolic hypertension, and atrial fibrillation, respectively. In conclusion, substantial cerebrovascular benefit could be realized with the institution of losartan-based therapy over conventional therapy among hypertensive patients with left ventricular hypertrophy across the spectrum of cardiovascular risk.
Electrocardiographic left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular (CV) morbidity and mortality. However, the predictive value of changes in the magnitude of electrocardiographic LVH criteria during antihypertensive therapy remains unclear.To test the hypothesis that lesser severity of electrocardiographic LVH during antihypertensive treatment is associated with decreased CV morbidity and mortality, independent of blood pressure levels and reduction and treatment modality.Double-blind, randomized, parallel-group study conducted in 1995-2001 among 9193 men and women with hypertension aged 55 through 80 years (mean, 67 years), with electrocardiographic LVH by Cornell voltage-duration product or Sokolow-Lyon voltage criteria and enrolled in the Losartan Intervention For Endpoint Reduction in Hypertension (LIFE) study.Losartan- or atenolol-based treatment regimens, with follow-up assessments for at least 4 (mean, 4.8 [SD, 0.9]) years.Composite end point of CV death, myocardial infarction (MI), or stroke in relation to severity of electrocardiographic LVH determined at baseline and on subsequent electrocardiograms obtained at 1 or more annual revisits.Cardiovascular death, nonfatal MI, or stroke occurred in 1096 patients (11.9%). In Cox regression models controlling for treatment type, baseline Framingham risk score, baseline and in-treatment blood pressure, and severity of baseline electrocardiographic LVH by Cornell product and Sokolow-Lyon voltage, less-severe in-treatment LVH by Cornell product and Sokolow-Lyon voltage were associated with 14% and 17% lower rates, respectively, of the composite CV end point (adjusted hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.82-0.90; P<.001 for every 1050-mm x ms [1-SD] decrease in Cornell product; and HR, 0.83; 95% CI, 0.78-0.88; P<.001 for every 10.5-mm [1-SD] decrease in Sokolow-Lyon voltage). In parallel analyses, lower Cornell product and Sokolow-Lyon voltage were each independently associated with lower risks of CV mortality (HR, 0.78; 95% CI, 0.73-0.83; P<.001; and HR, 0.80; 95% CI, 0.73-0.87; P<.001, respectively), MI (HR, 0.90; 95% CI, 0.82-0.98; P=.01; and HR, 0.90; 95% CI, 0.81-1.00; P = .04), and stroke (HR, 0.90; 95% CI, 0.84-0.96; P=.002; and HR, 0.81; 95% CI, 0.75-0.89; P<.001).Less-severe electrocardiographic LVH by Cornell product and Sokolow-Lyon voltage criteria during antihypertensive therapy is associated with lower likelihoods of CV morbidity and mortality, independent of blood pressure lowering and treatment modality in persons with essential hypertension. Antihypertensive therapy targeted at regression or prevention of electrocardiographic LVH may improve prognosis.
Malignant perivascular epithelioid cell tumor (PEComa) is a rare aggressive sarcoma, with no approved treatment. To our knowledge, this phase II, single-arm, registration trial is the first prospective clinical trial in this disease, investigating the safety and efficacy of the mammalian target of rapamycin inhibitor
8017 Background: Although BCMA is a plasma cell specific surface molecule attractive as an antibody target in multiple myeloma, its scarcity on the cell surface may limit the efficacy of a conventional antibody. T-cell engaging bispecific antibody approaches are highly efficacious and are particularly well suited for a membrane target with limited expression, such as BCMA. Teneobio has developed a multivalent antibody platform based on modular human VH domains, which allowed us to build T cell engaging bispecific antibodies with low and high T cell agonistic activities. Methods: UniRats were immunized with either CD3 or BCMA antigens and antigen-specific UniAbs were identified by antibody repertoire sequencing and high-throughput gene assembly, expression, and screening. High affinity binding VH sequences were selected using recombinant proteins and cells. In vitro efficacy studies included T-cell activation by cytokine- and tumor cell kill by calcein-release assays. In vivo efficacy of the molecules was evaluated in NSG mice harboring myeloma cells and human PBMCs. Results: BCMA-specific UniAbs bound plasma cells with high affinities (100-700pM) and cross-reacted with cynomolgus plasma cells. Strong and weak T cell agonists were identified that bound human T cells with high and low affinities respectively and cross-reacted with cynomolgus T cells. T cell engaging bispecifics with a strong (H929 cytotoxicity:EC 50 =27pM) and a weak T cell activating arm (H929 cytotoxicity: EC 50 =1170pM) demonstrated T-cell activation and tumor-cell cytotoxicity in vitro; bispecifics with a weak CD3 engaging arm showed markedly reduced cytokine production even at doses saturating for cytotoxicity. In viv o, BCMAxCD3 bispecific antibodies reduced tumor load and increased survival when co-administered with human PBMCs as compared to controls. Conclusions: Our results suggest that T cell engaging bispecifics with low-affinity anti-CD3 arms could be preferred for the treatment of Multiple Myeloma.
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