LFA-1 activation enriches tumor-specific T cells in a cold tumor model and synergizes with CTLA-4 blockade.

The inability of CD8+ effector T cells (Teffs) to reach tumor cells is an important aspect of tumor resistance to cancer immunotherapy. The recruitment of these cells to the tumor microenvironment (TME) is regulated by integrins, a family of adhesion molecules that are expressed on T cells. Here, we show that 7HP349, a small-molecule activator of lymphocyte function-associated antigen-1 (LFA-1) and very late activation antigen-4 (VLA-4) integrin cell-adhesion receptors, facilitated the preferential localization of tumor-specific T cells to the tumor and improved antitumor response. 7HP349 monotherapy had modest effects on anti-programmed death 1-resistant (anti-PD-1-resistant) tumors, whereas combinatorial treatment with anti-cytotoxic T lymphocyte-associated protein 4 (anti-CTLA-4) increased CD8+ Teff intratumoral sequestration and synergized in cooperation with neutrophils in inducing cancer regression. 7HP349 intratumoral CD8+ Teff enrichment activity depended on CXCL12. We analyzed gene expression profiles using RNA from baseline and on treatment tumor samples of 14 melanoma patients. We identified baseline CXCL12 gene expression as possibly improving the likelihood or response to anti-CTLA-4 therapies. Our results provide a proof-of-principle demonstration that LFA-1 activation could convert a T cell-exclusionary TME to a T cell-enriched TME through mechanisms involving cooperation with innate immune cells.

Use of a small molecule integrin activator as a systemically administered vaccine adjuvant in controlling Chagas disease.

The development of suitable safe adjuvants to enhance appropriate antigen-driven immune responses remains a challenge. Here we describe the adjuvant properties of a small molecule activator of the integrins αLß2 and α4ß1, named 7HP349, which can be safely delivered systemically independent of antigen. 7HP349 directly activates integrin cell adhesion receptors crucial for the generation of an immune response. When delivered systemically in a model of Chagas disease following immunization with a DNA subunit vaccine encoding candidate T. cruzi antigens, TcG2 and TcG4, 7HP349 enhanced the vaccine efficacy in both prophylactic and therapeutic settings. In a prophylactic setting, mice immunized with 7HP349 adjuvanted vaccine exhibited significantly improved control of acute parasite burden in cardiac and skeletal muscle as compared to vaccination alone. When administered with vaccine therapeutically, parasite burden was again decreased, with the greatest adjuvant effect of 7HP349 being noted in skeletal muscle. In both settings, adjuvantation with 7HP349 was effective in decreasing pathological inflammatory infiltrate, improving the integrity of tissue, and controlling tissue fibrosis in the heart and skeletal muscle of acutely and chronically infected Chagas mice. The positive effects correlated with increased splenic frequencies of CD8+T effector cells and an increase in the production of IFN-γ and cytolytic molecules (perforin and granzyme) by the CD4+ and CD8+ effector and central memory subsets in response to challenge infection. This demonstrates that 7HP349 can serve as a systemically administered adjuvant to enhance T cell-mediated immune responses to vaccines. This approach could be applied to numerous vaccines with no reformulation of existing stockpiles.

Bioavailability of aspirin in fasted and fed states of a novel pharmaceutical lipid aspirin complex formulation.

Dyspeptic symptoms are common with aspirin and clinicians frequently recommend that it be taken with food to reduce these side effects. However, food can interfere with absorption, especially with enteric-coated aspirin formulations. We evaluated whether food interferes with the bioavailability of a new, pharmaceutical lipid-aspirin complex (PL-ASA) liquid-filled capsule formulation. In this randomized, open label, crossover study, 20 healthy volunteers fasted for ≥ 10 h and then randomized as either "fasted", receiving 650 mg of PL-ASA, or as "fed", with a standard high-fat meal and 650 mg of PL-ASA 30 min later. After a washout of 7 days, participants crossed over to the other arm. The primary outcome was comparison of PK parameters of the stable aspirin metabolite salicylic acid (SA) between fasted and fed states. Mean age of participants was 36.8 years and 55% were male. The ratios for the fed to fasted states of the primary SA PK parameters of AUC0-t and AUC0-∞ were 88.7% and 88.8% respectively, with 90% confidence intervals between 80 and 125%, which is consistent with FDA bioequivalence guidance. Mean peak SA concentration was about 22% lower and occurred about 1.5 h later in the fed state. Food had a modest effect on peak SA levels and the time required to reach them after PL-ASA administration, but did not impact the extent of exposure (AUC) compared with intake in a fasted state. These data demonstrate that PL-ASA may be co-administered with food without significant impact on aspirin bioavailability.Clinical Trial Registration:http://www.clinicaltrials.gov Unique Identifier: NCT01244100.

Pharmacokinetic/pharmacodynamic assessment of a novel, pharmaceutical lipid-aspirin complex: results of a randomized, crossover, bioequivalence study.

Aspirin (acetylsalicylic acid, ASA) can lead to gastrointestinal mucosal injury through disruption of its protective phospholipid bilayer. A liquid formulation of a novel pharmaceutical lipid-aspirin complex (PL-ASA) was designed to prevent this disruption. We sought to determine the pharmacokinetic (PK)/pharmacodynamic (PD) characteristics of PL-ASA compared with immediate release aspirin (IR-ASA). In this active-control crossover study, 32 healthy volunteers were randomized to receive 1 of 2 dose levels (a single dose of 325 mg or 650 mg) of either PL-ASA or IR-ASA. After a 2-week washout period between treatment assignments, subjects received a single dose of the alternative treatment, at the same dose level. The primary objectives of the study were to assess, for PL-ASA and IR-ASA at 325 mg and 650 mg dose levels, PK and PD bioequivalence, and safety, over a 24-h period after administration of both drugs. PK parameters were similar for PL-ASA and IR-ASA, and met FDA-criteria for bioequivalence. Regarding PD, both drugs also showed Cmin TxB2 values below 3.1 ng/mL (cut-off associated with decreased cardiovascular events) and > 99% inhibition of serum TxB2 ( ≥ 95% inhibition represents the cut-off for aspirin responders) along with similar results in several secondary PK/PD parameters. There were no serious adverse events or changes from baseline in vital signs or laboratory values in either of the 2 treatment groups. PL-ASA's novel liquid formulation has similar PK and PD performance compared with IR-ASA, supporting functional and clinical equivalence. These data coupled with the improved gastric safety of PL-ASA suggest that this novel formulation may exhibit an improved benefit-risk profile, warranting evaluation in future trials.Clinical trial registration: http://www.clinicaltrials.gov . Unique Identifier: NCT04008979.

Enteric Coating and Aspirin Nonresponsiveness in Patients With Type 2 Diabetes Mellitus.

BACKGROUND: A limitation of aspirin is that some patients, particularly those with diabetes, may not have an optimal antiplatelet effect. OBJECTIVES: The goal of this study was to determine if oral bioavailability mediates nonresponsiveness. METHODS: The rate and extent of serum thromboxane generation and aspirin pharmacokinetics were measured in 40 patients with diabetes in a randomized, single-blind, triple-crossover study. Patients were exposed to three 325-mg aspirin formulations: plain aspirin, PL2200 (a modified-release lipid-based aspirin), and a delayed-release enteric-coated (EC) aspirin. Onset of antiplatelet activity was determined by the rate and extent of inhibition of serum thromboxane B2 (TXB2) generation. Aspirin nonresponsiveness was defined as a level of residual serum TXB2 associated with elevated thrombotic risk (<99.0% inhibition or TXB2 >3.1 ng/ml) within 72 h after 3 daily aspirin doses. RESULTS: The rate of aspirin nonresponsiveness was 15.8%, 8.1%, and 52.8% for plain aspirin, PL2200, and EC aspirin, respectively (p < 0.001 for both comparisons vs. EC aspirin; p = 0.30 for comparison between plain aspirin and PL2200). Similarly, 56% of EC aspirin-treated subjects had serum TXB2 levels >3.1 ng/ml, compared with 18% and 11% of subjects after administration of plain aspirin and PL2200 (p < 0.0001). Compared with findings for plain aspirin and PL2200, this high rate of nonresponsiveness with EC aspirin was associated with lower exposure to acetylsalicylic acid (63% and 70% lower geometric mean maximum plasma concentration [Cmax] and 77% and 82% lower AUC0-t [area under the curve from time 0 to the last time measured]) and 66% and 72% lower maximum decrease of TXB2, with marked interindividual variability. CONCLUSIONS: A high proportion of patients treated with EC aspirin failed to achieve complete inhibition of TXB2 generation due to incomplete absorption. Reduced bioavailability may contribute to "aspirin resistance" in patients with diabetes. (Pharmacodynamic Evaluation of PL2200 Versus Enteric-Coated and Immediate Release Aspirin in Diabetic Patients; NCT01515657).

Low-dose aspirin-induced ulceration is attenuated by aspirin-phosphatidylcholine: a randomized clinical trial.

OBJECTIVES: Relative contributions of local and systemic mechanisms of upper gastrointestinal (GI) injury following aspirin are unknown. Studies suggest that aspirin's GI risk is age related and that gastroprotection may be needed at therapy initiation. We determined acute gastroduodenal erosion and ulceration following low-dose aspirin and aspirin-phosphatidylcholine complex (PL2200) in subjects at risk of aspirin ulcers. METHODS: In a randomized, single blind, multicenter active-controlled study, we compared upper GI damage of aspirin and PL2200 in healthy subjects (n=204, ages 50-74 years) following 7 days of oral 325 mg once daily, immediate release aspirin or PL2200. RESULTS: Overall, 42.2% of aspirin-treated subjects developed multiple erosions and/or ulcers, whereas 22.2% treated with PL2200 developed such damage (P=0.0027). Gastroduodenal ulcers were observed in 17.6% of aspirin-treated compared with 5.1% of subjects treated with PL2200 (P=0.0069). CONCLUSIONS: Low-dose aspirin induced a surprisingly high incidence of acute gastroduodenal ulcers in at risk subjects, highlighting that aspirin's upper GI risk begins early and may require gastroprotection. Local mechanisms of GI protection are important as aspirin's preassociation with surface-active phospholipids significantly reduced mucosal damage. PL2200 may be an attractive alternative or complement to proton pump inhibitors in older patients who are at risk of aspirin-induced ulceration. Longer-term studies assessing clinical GI events are desirable to confirm the clinical GI safety profile of PL2200.

Association of phosphatidylcholine and NSAIDs as a novel strategy to reduce gastrointestinal toxicity.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are highly effective drugs that inhibit pain and inflammation, and perhaps due to the role of inflammation in the underlying etiology, NSAIDs have also demonstrated efficacy in reducing a patient's risk of developing a number of cancers and neurological diseases (e.g. Alzheimer's disease). The utility of these powerful drugs is limited due to their gastrointestinal (GI) side-effects, notably peptic ulceration and GI bleeding which is briefly reviewed here. We also describe the barrier property of the GI mucosa and how it is affected by NSAIDs, as it is our position that disruption of the surface barrier is an important component in the drugs' pathogenesis, in addition to selective inhibition of COX-2, which has proven to be problematic. We also discuss current alternative approaches being taken to mitigate the GI side-effects of NSAIDs, including developing combination drugs where NSAIDs are packaged with inhibitors of HCl secretion such as proton pump inhibitors or H2-receptor antagonists. We then present the rationale for the development of the PC associated NSAID technology which came out of our observation that the mammalian gastric mucosa has hydrophobic, nonwettable properties that provides a barrier to luminal acid, and the role of phospholipids and specifically phosphatidylcholine (PC) in this barrier property. In the last section we review the development of our current lipid-based PC-NSAID formulations and our encouraging preclinical and clinical observations validating their GI safety and therapeutic efficacy.