IL-7 coupled with IL-12 increases intratumoral T cell clonality, leading to complete regression of non-immunogenic tumors.

Immune checkpoint inhibitors against PD-1, PD-L1 and CTLA-4 have altered the treatment paradigm for various types of cancers in the past decade. However, they offer clinical benefits to only a subset of patients. Evaluation and identification of an appropriate therapeutic approach to improve intratumoral immune status are needed for better treatment outcomes. We previously demonstrated that intratumoral expression of IL-7 and IL-12 increased tumor-infiltrating lymphocytes in poorly immunogenic tumors, resulting in a higher tumor regression rate than IL-12 alone. However, the mechanism underlying the difference in efficacy with and without IL-7 remains unclear. Here, we identified a previously unknown effect of IL-7 on the T cell receptor (TCR) repertoire of intratumoral CD8+ T cells, which is induced in the presence of IL-12. While IL-7 alone increased the diversity of intratumoral CD8+ T cells, IL-7 with IL-12 increased a limited number of high-frequency clones, conversely augmenting IL-12 function to increase the clonality. The proportion of mice with multiple high-frequency clones in tumors correlated with that achieving complete tumor regression in efficacy studies. These findings provide a scientific rationale for combining IL-7 and IL-12 in anticancer immunotherapy and unveil a novel IL-7 function on intratumoral TCR repertoire.

Oncolytic vaccinia virus induces a novel phenotype of CD8+ effector T cells characterized by high ICOS expression.

Characterization of the intratumoral immune status is important for developing immunotherapies and evaluating their antitumor effectiveness. CD8+ T cells are one of the most important cell types that directly and indirectly contribute to antitumor efficacy by releasing cytolytic molecules and inflammatory cytokines in the tumor microenvironment. Previously, we engineered a tumor-selective oncolytic vaccinia virus that encodes interleukin-7 (IL-7) and IL-12 and demonstrated its usefulness as an agent for in situ vaccination against tumors, with data showing that antitumor efficacy was reliant upon CD8+ T cells recruited by viral treatment. Here, we investigated the phenotypic changes in intratumoral CD8+ T cells caused by this oncolytic virus and found increased expression of inducible co-stimulator (ICOS) in PD-1-CD8+ T cells. Unlike previously reported ICOS+CD8+ T cells, a subset of ICOS+PD-1-CD8+ T cells showed effector function characterized by granzyme B expression. ICOS expression was induced by the backbone virus, which did not encode any immune transgenes and was independent of upregulation of the type I interferon pathway. Not only did we identify a novel effector cell subset characterized by ICOS expression, but our findings also shed light on a potential unknown aspect of the mechanism of oncolytic vaccinia virotherapy.

Intratumoral expression of IL-7 and IL-12 using an oncolytic virus increases systemic sensitivity to immune checkpoint blockade.

The immune status of the tumor microenvironment is a key indicator in determining the antitumor effectiveness of immunotherapies. Data support the role of activation and expansion of tumor-infiltrating lymphocytes (TILs) in increasing the benefit of immunotherapies in patients with solid tumors. We found that intratumoral injection of a tumor-selective oncolytic vaccinia virus encoding interleukin-7 (IL-7) and IL-12 into tumor-bearing immunocompetent mice activated the inflammatory immune status of previously poorly immunogenic tumors and resulted in complete tumor regression, even in distant tumor deposits. Mice achieving complete tumor regression resisted rechallenge with the same tumor cells, suggesting establishment of long-term tumor-specific immune memory. Combining this virotherapy with anti-programmed cell death-1 (PD-1) or anti-cytotoxic T lymphocyte antigen 4 (CTLA4) antibody further increased the antitumor activity as compared to virotherapy alone, in tumor models unresponsive to either of the checkpoint inhibitor monotherapies. These findings suggest that administration of an oncolytic vaccinia virus carrying genes encoding for IL-7 and IL-12 has antitumor activity in both directly injected and distant noninjected tumors through immune status changes rendering tumors sensitive to immune checkpoint blockade. The benefit of intratumoral IL-7 and IL-12 expression was also observed in humanized mice bearing human cancer cells. These data support further investigation in patients with non-inflamed solid tumors.

Vasopressin receptor antagonists: potential indications and clinical results.

Hyponatremia is a common electrolyte disorder with the potential to cause serious neurological complications. Conventional therapies for hyponatremia have been found to be inconsistently effective. Arginine vasopressin (AVP) is etiologically critical for hyponatremia, and it has been proven that AVP receptor (AVP-R) antagonists normalize serum sodium levels in hyponatremic patients. Additionally, one of these drugs showed potential for reducing mortality in patients with decompensated heart failure and for suppressing the progression of genetic renal disease in animals. The first non-peptide AVP-R antagonist has recently been approved in the United States. It is expected that this approval will accelerate the development of future clinical applications of AVP-R antagonists and open the door to a new era in the treatment of these intractable diseases.

ASP9853, an inhibitor of inducible nitric oxide synthase dimerization, in combination with docetaxel: preclinical investigation and a Phase I study in advanced solid tumors.

PURPOSE: ASP9853 is an inhibitor of inducible nitric oxide (NO) synthase (iNOS) dimerization, which results in decreased NO production. Here, we report preclinical pharmacology of ASP9853 and the impact of ASP9853 in combination with a taxane on tumor volume in vivo. In addition, a Phase I open-label study of ASP9853 plus docetaxel was conducted to assess this combination in patients with advanced solid tumors. METHODS: The preclinical efficacy of ASP9853 in combination with a taxane was studied in tumor-bearing mice. In the clinic, patients with solid tumors that had progressed or failed to respond to previous therapies were treated with once-daily ASP9853 in combination with docetaxel once every 3 weeks to assess safety and tolerability and to determine the maximum tolerated dose (MTD) and the recommended Phase II dose (RP2D) of the combination. RESULTS: ASP9853 in combination with docetaxel showed greater tumor growth inhibition than docetaxel alone against non-small lung cancer xenografts. Twenty patients were treated with ASP9853 and docetaxel. Five patients experienced neutropenic dose-limiting toxicities. Owing to overall toxicity that limited further dose escalation, the ASP9853 concentrations predicted for efficacy, based on the preclinical data, were not achieved. Due to toxicity and lack of clear efficacy, the study was terminated without determination of MTD or RP2D. CONCLUSIONS: Inhibition of iNOS by ASP9853 in combination with docetaxel was not tolerable and resulted in the possible potentiation of neutropenia. Manipulation of the iNOS pathway, with or without chemotherapy, appears to be more complicated than initially expected.

Intravenous administration of conivaptan hydrochloride improves cardiac hemodynamics in rats with myocardial infarction-induced congestive heart failure.

We investigated the effects of intravenously administered conivaptan hydrochloride, a dual vasopressin V1A and V2 receptor antagonist, on cardiac function in rats with congestive heart failure following myocardial infarction, and compared results with those for the selective vasopressin V2 receptor antagonist SR121463A. Rats were subjected to left coronary artery occlusion to induce myocardial infarction, which in turn led to congestive heart failure. At 4 weeks after coronary occlusion, conivaptan (0.03, 0.1 and 0.3 mg/kg i.v.) dose-dependently increased urine volume and reduced urine osmolality in both myocardial infarction and sham-operated rats. SR121463A (0.3 mg/kg i.v.) also increased urine volume and decreased urine osmolality in myocardial infarction rats, to a degree comparable to that by conivaptan (0.3 mg/kg i.v.). At 6 weeks after surgery, myocardial infarction rats showed increases in right ventricular systolic pressure, right atrial pressure, left ventricular end-diastolic pressure and relative weights of the heart and the lungs, and a decrease in first derivative of left ventricular pressure (dP/dt(max))/left ventricular pressure, showing that congestive heart failure was well established. Conivaptan (0.3 mg/kg i.v.) significantly reduced right ventricular systolic pressure, left ventricular end-diastolic pressure, lung/body weight and right atrial pressure in myocardial infarction rats. Moreover, conivaptan (0.3 mg/kg i.v.) significantly increased dP/dt(max)/left ventricular pressure. SR121463A at a dose of 0.3 mg/kg i.v. significantly decreased left ventricular end-diastolic pressure and right atrial pressure, and tended to decrease right ventricular systolic pressure and relative lung weight in myocardial infarction rats. Although the aquaretic and preload-reducing effects of SR121463A were similar to those of conivaptan, SR121463A failed to improve dP/dt(max)/left ventricular pressure. These results suggest that dual vasopressin V1A and V2 receptor antagonists provide greater benefit than selective vasopressin V2 receptor antagonists in the treatment of congestive heart failure.

Effect of the vasopressin receptor antagonist conivaptan in rats with heart failure following myocardial infarction.

Myocardial infarction often induces congestive heart failure accompanied by a significant increase in plasma vasopressin concentration. To delineate the role of vasopressin in the pathogenesis of congestive heart failure, the acute hemodynamic and aquaretic effects of conivaptan (YM087, 4'-(2-methyl-1,4,5,6-tetrahydroimidazo[4,5-d][1]benzoazepine-6-carbonyl)-2-phenylbenzanilide monohydrochloride), a combined vasopressin V(1A) and V(2) receptor antagonist, were assessed in rats with heart failure induced by myocardial infarction. Left coronary artery ligation resulted in decreased left ventricular systolic pressure and first derivatives of left ventricular developed pressure, as well as increased left ventricular end-diastolic pressure, lung and right ventricular weight. Single oral administration of conivaptan (0.3 to 3.0 mg/kg) dose-dependently increased urine volume and decreased urine osmolality in heart failure rats. Furthermore, conivaptan (3.0 mg/kg) attenuated the changes in left ventricular end-diastolic pressure, lung and right ventricular weight induced by heart failure while reducing blood pressure. These results show that vasopressin plays a significant role in elevating vascular tone through vasopressin V(1A) receptors and plays a major role in retaining free water through vasopressin V(2) receptors in this model of congestive heart failure. Additionally, conivaptan, with its dual vasopressin V(1A) and V(2) receptor-inhibiting properties, could exert a beneficial effect on cardiac function in the congestive heart failure rat model.

New topics in vasopressin receptors and approach to novel drugs: research and development of conivaptan hydrochloride (YM087), a drug for the treatment of hyponatremia.

Hyponatremia is the most common electrolyte disorder in hospitalized patients and is associated with the risk of intractable seizures and death. The effectiveness of conventional therapies for hyponatremia is inconsistent, and the rapid correction of plasma sodium levels is thought to result in the occurrence of neurological complications. Arginine vasopressin (AVP) is the primary regulator of renal electrolyte-free water reabsorption via AVP-receptor type 2 (V2-R), and inappropriate or excessive AVP secretion independent of serum osmolality frequently causes excessive water retention, which is the etiological basis of hyponatremia. Therefore, the use of V2-R antagonists as anti-hyponatremic drugs in the clinical setting is anticipated to be reliable and safe. Conivaptan hydrochloride (YM087) is a novel dual AVP-R antagonist for AVP-R types 1a (V1a) and V2-R. In vitro studies have shown that it possesses high affinity for V1a-R and V2-R without any species differences. It also potently inhibited AVP-induced intracellular signaling through human V2 and V1a receptors with no agonistic activity. Conivaptan hydrochloride improved the plasma sodium concentration and plasma osmolality in hyponatremic rats, and its effectiveness was demonstrated in hyponatremic patients. This drug has been approved for use in the United States, which will bring relief to patients with hyponatremia.

A novel vasopressin dual V1A/V2 receptor antagonist, conivaptan hydrochloride, improves hyponatremia in rats with syndrome of inappropriate secretion of antidiuretic hormone (SIADH).

We investigated the effects of intravenous administration of conivaptan hydrochloride, a dual vasopressin V1A and V2 receptor antagonist, on blood electrolytes and plasma osmolality in rats with an experimental syndrome of inappropriate secretion of antidiuretic hormone (SIADH). The experimental SIADH rat model was developed by means of continuous administration of arginine vasopressin (AVP) via a subcutaneously implanted osmotic mini pump, and hyponatremia was induced by additional water loading. This model possesses similar characteristics to those observed in patients with SIADH, specifically decreases in blood sodium concentration and plasma osmolality. In this experimental model, intravenous administration of conivaptan (0.1, 1 mg/kg) significantly increased blood sodium concentration and plasma osmolality. On the other hand, intravenous administration of furosemide (10 mg/kg) did not increase either blood sodium concentration or plasma osmolality in the SIADH rats. Moreover, furosemide significantly lowered blood potassium concentration. These results show that conivaptan improves hyponatremia in rats with SIADH, supporting the therapeutic potential of conivaptan in treatment of patients with hyponatremia associated with SIADH.

Effect of conivaptan, a combined vasopressin V(1a) and V(2) receptor antagonist, on vasopressin-induced cardiac and haemodynamic changes in anaesthetised dogs.

The neurohormonal factor arginine vasopressin (AVP) produces potent systemic vasoconstriction as well as water retention in the kidneys via the V(1a) and V(2) receptors, respectively. Therefore, AVP may be considered as an aggravating factor of cardiac failure. In the present study, the effects of intravenous (i.v.) infusion of AVP on cardiovascular parameters and the effect of conivaptan (YM087, 4'-(2-methyl-1,4,5,6-tetrahydroimidazo[4,5-d][1]benzoazepine-6-carbonyl)-2-phenylbenzanilide monohydrochloride), a vasopressin V(1a)/V(2) receptor antagonist, on AVP-induced cardiac and haemodynamic changes were investigated in pentobarbitone-anaesthetised dogs. The i.v. infusion of AVP (0.12-4mUkg(-1)min(-1)) dose-dependently produced decreases in the cardiac contractility indicator LV dP/dt(max) and cardiac output (CO) and increases in left ventricular end-diastolic pressure (LVEDP) and total peripheral resistance (TPR). These changes accurately mimic the cardiovascular symptoms of congestive heart failure. The i.v. bolus injection of conivaptan (0.1mgkg(-1)) rapidly attenuated the AVP (4mUkg(-1)min(-1))-induced decrease in CO and reversed the AVP-induced elevation in both LVEDP and TPR. In conclusion, i.v. infusion of AVP produced cardiac dysfunction and vasoconstriction in pentobarbitone-anaesthetised dogs. Conivaptan demonstrated the ability to dramatically improve the impaired cardiovascular parameters induced by AVP. The results suggest the potential usefulness of conivaptan in treating congestive heart failure.