Blood microsampling in cynomolgus monkey and evaluation of plasma PK parameters in comparison to conventional sampling

Microsampling, a reduced volume sampling method, has successfully gained attention at the International Conference on Harmonization (ICH) level and established benefits support its use in Toxicokinetic (TK) studies. These improved sampling techniques are less invasive and in large animal species improve animal welfare (refinement). To evaluate if the plasma concentrations of drugs were influenced by the blood sampling method, the traditional method from femoral vein and microsampling from tail vein in Cynomolgus monkeys were compared. The pharmacokinetic parameters (Cmax, Tmax and AUC) of four drugs (selected based on acid-base and volume of distribution properties) in non-human primate were correlated. The plasma samples were quantified using standard LC-MS/MS methods, qualified to evaluate the precision and accuracy before the analysis of real samples. The results reported in this work demonstrated the suitability of microsampling in supporting PK/TK studies in non-human primates. The data show that the exposure of drugs tested after blood collection using standard procedure from femoral vein and microsampling from tail vein is correlated and is not influenced by acid-base characteristics and volume of distribution.

Characterization and translational development of IOA-289, a novel autotaxin inhibitor for the treatment of solid tumors

Background

Autotaxin-lysophosphatidic acid (ATX-LPA) signaling has a predominant role in immunological and fibrotic processes, including cancer. Several ATX inhibitors and LPA receptor antagonists have been clinically evaluated, but none in patients with solid tumors. Many cancers are burdened with a high degree of fibrosis and an immune desert phenotype (so-called 'cold' tumors). In these cold tumors, the fibrotic stroma provides an intrinsic cancer-supporting mechanism. Furthermore, the stroma prevents penetration and limits the effectiveness of existing therapies. IOA-289 is a novel ATX inhibitor with a unique chemical structure, excellent potency and an attractive safety profile.

Materials and methods

In vitro and in vivo pharmacology studies have been carried out to elucidate the pharmaceutical properties and mechanism of action of IOA-289. A phase I clinical study in healthy volunteers was carried out to determine the pharmacokinetics and pharmacodynamics of IOA-289 following a single oral dose.

Results

In vitro and in vivo studies showed that IOA-289 is a potent inhibitor of ATX and, as a monotherapy, is able to slow progression of lung fibrosis and tumor growth in mouse models. In a clinical study, IOA-289 showed a dose-dependent increase in plasma exposure levels and a corresponding decrease in circulating LPA.

Conclusions

Our data show that IOA-289 is a novel ATX inhibitor with a unique chemical structure, excellent potency and an attractive safety profile. Our data support the further development of IOA-289 as a novel therapeutic approach for the treatment of cancer, particularly those with a high fibrotic and immunologically cold phenotype.

Abstract 2636: Targeting Autotaxin to suppress stromal signaling in the tumor microenvironment to improve outcome to therapy in fibrotic tumor types

Recent findings indicate that in cancer, host immune suppression and resistance to therapy is orchestrated by the presence and activity of stromal cells in the tumor microenvironment. Therefore novel approaches to overcome stromal mediated resistance to therapy represent a potential strategy to improve the outcome to chemotherapy and immune checkpoint blockade, particularly in tumors that have a fibrotic microenviroment. Autotaxin is an enzyme that converts Lysophosphatidylcholine (LPC) to Lysophosphatidic Acid (LPA), a key pathway that is aberrantly activated in fibrosis. LPA has also been described to act directly on tumor cells, promoting their growth and proliferation via G protein-coupled LPA Receptors (LPARs). IOA-289 is a novel, potent, selective and orally bioavailable inhibitor of Autotaxin, a target with known clinical application in fibrotic diseases and with a strong rationale for exploration in cancer.

In preclinical models, IOA-289 modulated levels of circulating LPA in a dose dependent manner. At doses achieving at least 50% reduction of circulating LPA, IOA-289 showed monotherapeutic efficacy in in vivo mouse models of cancer. Notably the effects were most prominent in orthotopic models that recapitulate the stromal components of the microenvironment. In vitro studies investigated the mechanism of action of IOA-289, and it was shown to be driven by:

(i)Direct anti-tumor activity on cancer cell lines in vitro (ii)Modulation of the secretory profile of fibroblasts(iii)Increased T cell infiltration in vitro and in vivo

In a healthy volunteer study following a single oral ascending dose, IOA-289 showed a dose dependent increase in plasma and a corresponding decrease in circulating LPA. We also demonstrated that ATX was elevated in plasma from pancreatic cancer patients compared to samples from healthy volunteers and are correlated with soluble CA19-9.

Based on our preclinical data we postulate that inhibition of the ATX/LPA pathway with IOA-289 may be a beneficial therapeutic strategy for cancer patients with fibrotic tumor microenvironments. The predicted biologically effective dose of IOA-289 has been calculated using PK/PD modelling combining data from preclinical studies and from the phase Ia healthy volunteer study. IOA-289 is scheduled to enter a phase Ib clinical trial in pancreatic cancer.

Citation Format: Zoe Johnson, Marcel Deken, Ragini Medhi, Lauren Maggs, Alan Carruthers, Anne Cheasty, Alessia Tagliavini, Andrea Nizzardo, Marco Pergher, Karolina Niewola, Amy Fraser, Lars van der Veen, Pritom Shah, Luigi ZIviani, Stefano Milleri, Michael Lahn. Targeting Autotaxin to suppress stromal signaling in the tumor microenvironment to improve outcome to therapy in fibrotic tumor types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2636.

CLI24-001: First-in-human study of SEL24/MEN1703, an oral dual PIM/FLT3 kinase inhibitor, in patients with acute myeloid leukemia

TPS7062

Background: FLT3-ITD is one of the most common genetic lesions in acute myeloid leukemia (AML). PIM kinases are oncogenic FLT3-ITD targets expressed in AML cells and increased PIM kinase expression is found in relapse samples from AML patients treated with FLT3 inhibitors. In addition, inhibition of PIM kinases restores sensitivity to FLT3 inhibitors and dual FLT3/PIM inhibition eradicates FLT3-ITD+ cells including primary AML cells. SEL24/MEN1703, a potent PIM/FLT3 dual inhibitor, demonstrates a significantly broader spectrum of activity in AML cell lines and primary AML blasts, irrespective of FLT3 status, compared to monotherapy with either FLT3 or PIM inhibitors such as quizartinib or AZD1208. Methods: CLI24-001 is a First in Human, open label, non-randomized, multi-center, Phase I/II dose-escalation and cohort expansion study of SEL24/MEN1703 in AML patients (excluding APL) not suitable for chemotherapy. SEL24/MEN1703 is given orally, QD, for 14 days in a 21-day cycle with cycles repeated until disease progression or unacceptable toxicity. Dose escalation follows a 3+3 design to identify the recommended phase 2 dose (RP2D). In the phase 2 part/cohort expansion, subjects will receive SEL24/MEN1703 at the RP2D, to further investigate the safety profile and signs of antileukemic activity. In both study parts, patients are eligible regardless of mutational status and/or prior exposure to FLT3 inhibitors; prior treatment with PIM inhibitors is not allowed. Main inclusion criteria comprise a white blood count (WBC) of ≤30 x 109/L (hydroxyurea/leukoapheresis permitted to lower WBC). Key secondary objectives include pharmacokinetics (PK) and single agent efficacy. The study is enrolling at 5 US sites and will be extended, both in US and EU, in the cohort expansion part. This is the first trial testing a dual PIM/FLT3 inhibitor with the potential to be active in AML regardless of FLT3 status andwith a potential to overcome FLT3 inhibitor resistance. (Sci Adv. 2015;1:e1500221; Oncotarget. 2018 Mar 30;9(24):16917-16931) Clinical trial information: NCT03008187.

Calcium signaling and secretory granule pool dynamics underlie biphasic insulin secretion and its amplification by glucose: experiments and modeling

Glucose-stimulated insulin secretion from pancreatic β-cells is controlled by a triggering pathway that culminates in calcium influx and regulated exocytosis of secretory granules, and by a less understood amplifying pathway that augments calcium-induced exocytosis. In response to an abrupt increase in glucose concentration, insulin secretion exhibits a first peak followed by a lower sustained second phase. This biphasic secretion pattern is disturbed in diabetes. It has been attributed to depletion and subsequent refilling of a readily releasable pool of granules or to the phasic cytosolic calcium dynamics induced by glucose. Here, we apply mathematical modeling to experimental data from mouse islets to investigate how calcium and granule pool dynamics interact to control dynamic insulin secretion. Experimental calcium traces are used as inputs in three increasingly complex models of pool dynamics, which are fitted to insulin secretory patterns obtained using a set of protocols of glucose and tolbutamide stimulation. New calcium and secretion data for so-called staircase protocols, in which the glucose concentration is progressively increased, are presented. These data can be reproduced without assuming any heterogeneity in the model, in contrast to previous modeling, because of nontrivial calcium dynamics. We find that amplification by glucose can be explained by increased mobilization and priming of granules. Overall, our results indicate that calcium dynamics contribute substantially to shaping insulin secretion kinetics, which implies that better insight into the events creating phasic calcium changes in human β-cells is needed to understand the cellular mechanisms that disturb biphasic insulin secretion in diabetes.

Spatiotemporal Modeling of Triggering and Amplifying Pathways in GLP-1 Secreting Intestinal L Cells

Glucagon-like peptide 1 (GLP-1) is secreted by intestinal L-cells, and augments glucose-induced insulin secretion, thus playing an important role in glucose control. The stimulus-secretion pathway in L-cells is still incompletely understood and a topic of debate. It is known that GLP-1 secreting cells can sense glucose to promote electrical activity either by the electrogenic sodium-glucose cotransporter SGLT1, or by closure of ATP-sensitive potassium channels after glucose metabolism. Glucose also has an effect on GLP-1 secretion downstream of electrical activity. An important aspect to take into account is the spatial organization of the cell. Indeed, the glucose transporter GLUT2 is located at the basolateral, vascular side, while SGLT1 is exposed to luminal glucose at the apical side of the cell, suggesting that the two types of transporters play different roles in glucose sensing. Here, we extend our recent model of electrical activity in primary L-cells to include spatiotemporal glucose and Ca2+ dynamics, and GLP-1 secretion. The model confirmed that glucose transportation into the cell through SGLT1 cotransporters can induce Ca2+ influx and release of GLP-1 as a result of electrical activity, while glucose metabolism alone is insufficient to depolarize the cell and evoke GLP-1 secretion in the model, suggesting a crucial role for SGLT1 in triggering GLP-1 release in agreement with experimental studies. We suggest a secondary, but participating, role of GLUT2 and glucose metabolism for GLP-1 secretion via an amplifying pathway that increases the secretion rate at a given Ca2+ level.

Recent advances in mathematical modeling and statistical analysis of exocytosis in endocrine cells

Most endocrine cells secrete hormones as a result of Ca²⁺-regulated exocytosis, i.e., fusion of the membranes of hormone-containing secretory granules with the cell membrane, which allows the hormone molecules to escape to the extracellular space. As in neurons, electrical activity and cell depolarization open voltage-sensitive Ca²⁺ channels, and the resulting Ca²⁺ influx elevate the intracellular Ca²⁺ concentration, which in turn causes exocytosis. Whereas the main molecular components involved in exocytosis are increasingly well understood, quantitative understanding of the dynamical aspects of exocytosis is still lacking. Due to the nontrivial spatiotemporal Ca²⁺ dynamics, which depends on the particular pattern of electrical activity as well as Ca²⁺ channel kinetics, exocytosis is dependent on the spatial arrangement of Ca²⁺ channels and secretory granules. For example, the creation of local Ca²⁺ microdomains, where the Ca²⁺ concentration reaches tens of µM, are believed to be important for triggering exocytosis. Spatiotemporal simulations of buffered Ca²⁺ diffusion have provided important insight into the interplay between electrical activity, Ca²⁺ channel kinetics, and the location of granules and Ca²⁺ channels. By confronting simulations with statistical time-to-event (or survival) regression analysis of single granule exocytosis monitored with TIRF microscopy, a direct connection between location and rate of exocytosis can be obtained at the local, single-granule level. To get insight into whole-cell secretion, simplifications of the full spatiotemporal dynamics have shown to be highly helpful. Here, we provide an overview of recent approaches and results for quantitative analysis of Ca²⁺ regulated exocytosis of hormone-containing granules.

Is bursting more effective than spiking in evoking pituitary hormone secretion? A spatiotemporal simulation study of calcium and granule dynamics

Endocrine cells of the pituitary gland secrete a number of hormones, and the amount of hormone released by a cell is controlled in large part by the cell's electrical activity and subsequent Ca(2+) influx. Typical electrical behaviors of pituitary cells include continuous spiking and so-called pseudo-plateau bursting. It has been shown that the amplitude of Ca(2+) fluctuations is greater in bursting cells, leading to the hypothesis that bursting cells release more hormone than spiking cells. In this work, we apply computer simulations to test this hypothesis. We use experimental recordings of electrical activity as input to mathematical models of Ca(2+) channel activity, buffered Ca(2+) diffusion, and Ca(2+)-driven exocytosis. To compare the efficacy of spiking and bursting on the same cell, we pharmacologically block the large-conductance potassium (BK) current from a bursting cell or add a BK current to a spiking cell via dynamic clamp. We find that bursting is generally at least as effective as spiking at evoking hormone release and is often considerably more effective, even when normalizing to Ca(2+) influx. Our hybrid experimental/modeling approach confirms that adding a BK-type K(+) current, which is typically associated with decreased cell activity and reduced secretion, can actually produce an increase in hormone secretion, as suggested earlier.

Reactive oxygen and nitrogen species disturb Ca(2+) oscillations in insulin-secreting MIN6 β-cells

Disturbances in pulsatile insulin secretion and Ca(2+) oscillations in pancreatic β-cells are early markers of diabetes, but the underlying mechanisms are still incompletely understood. Reactive oxygen/nitrogen species (ROS/RNS) are implicated in reduced β-cell function, and ROS/RNS target several Ca(2+) pumps and channels. Thus, we hypothesized that ROS/RNS could disturb Ca(2+) oscillations and downstream insulin pulsatility. We show that ROS/RNS production by photoactivation of aluminum phthalocyanine chloride (AlClPc) abolish or accelerate Ca(2+) oscillations in the MIN6 β-cell line, depending on the amount of ROS/RNS. Application of the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitor thapsigargin modifies the Ca(2+) response to high concentrations of ROS/RNS. Further, thapsigargin produces effects that resemble those elicited by moderate ROS/RNS production. These results indicate that ROS/RNS interfere with endoplasmic reticulum Ca(2+) handling. This idea is supported by theoretical studies using a mathematical model of Ca(2+) handling adapted to MIN6 cells. Our results suggest a putative link between ROS/RNS and disturbed pulsatile insulin secretion.

The use of the computer in a long-term review of 315 fractures of the proximal end of the femur

The authors present a computer analysis of 315 fractures of the proximal end of the femur. The data were placed in an M24 computer which had previously been programmed for a recording of traumatological cases. Unstable pertrochanteric fractures are discussed in particular, as well as the results obtained in relation to the type of osteosynthesis used.

[Skin metastases of lung cancer: clinical and prognostic significance]

Two cases of bronchial carcinoma with cutaneous metastasis are reported with emphasis on the rarity of the event, the clinical and histological aspects and the prognosis for such metastases.