Antineoplastic activity of GP-2250 in-vitro and in mouse xenograft models.

This study examined the antineoplastic effects of GP-2250 (misetionamide), an oxathiazine derivative with broad activity, in multiple cancer cell lines and mouse xenograft models. Antineoplastic activity of GP-2250 was tested in >300 cancer cell lines using the OncoPanel cytotoxicity assay. GP-2250 activity was further tested in mouse xenograft models, in which GP-2250 or vehicle (10 ml/kg) was administered daily for 28 days by intraperitoneal injection in the lower right abdomen of CrTac:NCR-Foxn1nu mice with tumor volumes of 100 to 200 mm 3 . In the in-vitro models, GP-2250 increased cytotoxicity readings with IC50 and EC50 as well as indications of cell cycle blockage in pancreatic and ovarian cell lines. In mouse xenograft models, a reduction of 30-40% in tumor volume occurred in the GP-2250 group versus the vehicle group. On the final day of the study, tumor progression was significantly reduced in 4 tumor types: HT-29 in the GP-2250 500 and 1000 mg/kg groups, SKOV-3 in all GP-2250 treatment groups, Cal-27 in the GP-2250 1000 mg/kg group, and Hs-695T in the GP-2250 250 and 1000 mg/kg groups. Tumor regression in Cal-27 tumors was dose-dependent. GP-2250 demonstrated cytotoxic activity in vitro and reduced the tumor volume in a variety of human cancer cell lines in a xenograft mouse model. Given these results, as well as evidence of synergism with other anticancer drugs, GP-2250 shows promise as a new therapeutic agent for treating human cancers and is being evaluated in a phase 1 dose-escalation study (NCT03854100).

Single-dose ciraparantag safely and completely reverses anticoagulant effects of edoxaban.

Of the new direct oral anticoagulants, direct factor Xa inhibitors are limited by the absence of a proven reversal agent. We assessed the safety, tolerability and impact on anticoagulation reversal of ciraparantag (PER977) alone and following a 60 mg dose of the FXa inhibitor edoxaban. Escalating, single IV doses of ciraparantag were administered alone and following a 60 mg oral dose of edoxaban in a double-blind, placebo-controlled fashion to healthy subjects. Serial assessments of the pharmacokinetics and pharmacodynamic effects of ciraparantag were performed. Eighty male subjects completed the study. Following edoxaban (60 mg), a single IV dose of ciraparantag (100 to 300 mg) demonstrated full reversal of anticoagulation within 10 minutes and sustained for 24 hours. Fibrin diameter within clots was restored to normal 30 minutes after a single dose of 100 to 300 mg ciraparantag as determined by scanning electron microscopy and change in fibrin diameter quantified by automated image analysis. Potentially related adverse events were periorbital and facial flushing and cool sensation following IV injection of ciraparantag. Renal excretion of ciraparantag metabolite was the main elimination route. There was no evidence of procoagulant activity following ciraparantag as assessed by D-dimer, prothrombin fragments 1.2, and tissue factor pathway inhibitor levels. In conclusion, ciraparantag in healthy subjects is safe and well tolerated with minor, non-dose limiting adverse events. Baseline haemostasis was restored from the anticoagulated state with doses of 100 to 300 mg ciraparantag within 10-30 minutes of administration and sustained for at least 24 hours.

Ciraparantag safely and completely reverses the anticoagulant effects of low molecular weight heparin.

Major bleeding with low molecular weight heparin (LMWH) therapy occurs in up to 5% of patients and its anticoagulation is only partially reversed by protamine sulfate. We studied the ability of ciraparantag (PER977), a novel agent that reverses LMWH in preclinical studies, to reverse LMWH in healthy volunteers. METHODS: In this phase 1/2 trial, 4 cohorts of 10 healthy volunteers received escalating doses of ciraparantag (100 to 300mg) or placebo (8:2 ratio) approximately 4h after a single subcutaneous dose of enoxaparin, 1.5mg/kg. Safety, pharmacokinetic and pharmacodynamic effects were assessed. RESULTS: Complete reversal of enoxaparin anticoagulation, measured by a reduction of whole blood clotting time, was observed in all subjects who received a single ciraparantag dose ranging from 100mg to 300mg. The anticoagulation reversal occurred rapidly after bolus injection and persisted for the duration of the study. At 12h and 24h, the differences in whole blood clotting time in the treated group compared to placebo were no longer significant, consistent with the decline in enoxaparin concentrations and anticoagulation effects. No procoagulant signals were detected as measured by D-dimer, F1.2, and tissue factor pathway inhibitor levels. Ciraparantag was well tolerated with only transient, minor side effects. CONCLUSION: Ciraparantag reverses the whole blood clotting time induced by enoxaparin in a dose related manner and produces no procoagulant signal or deleterious adverse events in doses up to 300mg.

Novel oral anticoagulants and reversal agents: Considerations for clinical development.

This white paper provides a summary of presentations and discussions that were held at an Anticoagulant-Induced Bleeding and Reversal Agents Think Tank co-sponsored by the Cardiac Safety Research Consortium and the US Food and Drug Administration (FDA) at the FDA's White Oak Headquarters on April 22, 2014. Attention focused on a development pathway for reversal agents for the novel oral anticoagulants (NOACs). This is important because anticoagulation is still widely underused for stroke prevention in patients with atrial fibrillation. Undertreatment persists, although NOACs, in general, overcome some of the difficulties associated with anticoagulation provided by vitamin K antagonists. One reason for the lack of a wider uptake is the absence of NOAC reversal agents. As there are neither widely accepted academic and industry standards nor a definitive regulatory policy on the development of such reversal agents, this meeting provided a forum for leaders in the fields of cardiovascular clinical trials and cardiovascular safety to discuss the issues and develop recommendations. Attendees included representatives from pharmaceutical companies; regulatory agencies; end point adjudication specialist groups; contract research organizations; and active, academically based physicians. There was wide and solid consensus that NOACs overall offer improvements in convenience, efficacy, and safety compared with warfarin, even without reversal agents. Still, it was broadly accepted that it would be helpful to have reversal agents available for clinicians to use. Because it is not feasible to do definitive outcomes studies demonstrating a reversal agent's clinical benefits, it was felt that these agents could be approved for use in life-threatening bleeding situations if the molecules were well characterized preclinically, their pharmacodynamic and pharmacokinetic profiles were well understood, and showed no harmful adverse events in early human testing. There was also consensus that after such approval, efforts should be made to augment the available clinical information until such time as there is a body of evidence to demonstrate real-world clinical outcomes with the reversal agents. No recommendations were made for more generalized use of these agents in the setting of non-life-threatening situations. This article reflects the views of the authors and should not be construed to represent FDA's views or policies.

Reversal agents in development for the new oral anticoagulants.

The new oral anticoagulants have many advantages over vitamin K antagonists, but they are still associated with a troublesome incidence of major bleeding. Additionally, the absence of a reversal agent for the new oral anticoagulants is a barrier to their more widespread use. Currently, there are 3 potential reversal agents in development: idarucizumab is a humanized murine monoclonal antibody fragment directed specifically at dabigatran; andexanet alfa is a recombinant modified decoy factor Xa that binds to factor Xa inhibitors; and PER977 is a small molecule that binds to factor Xa and IIa inhibitors and to heparin-based anticoagulants through charge interaction. These agents have undergone phase I clinical testing, appear to be well tolerated in healthy volunteers, and are effective in neutralizing their respective targets. All 3 are currently undergoing or entering into a phase II or III clinical study. This article reviews the available data for idarucizumab, andexanet alfa, and PER977.