Efficacy and safety of early versus late glycoprotein IIb/IIIa inhibitors for PCI

Critical Analysis of Thrombocytopenia Associated With Glycoprotein IIb/IIIa Inhibitors and Potential Role of Zalunfiban, a Novel Small Molecule Glycoprotein Inhibitor, in Understanding the Mechanism(s)

Thrombocytopenia is a rare but serious complication of the intravenous glycoprotein IIb/IIIa (GPIIb/IIIa; integrin αIIbβ3) receptor inhibitors (GPIs), abciximab, eptifibatide, and tirofiban. The thrombocytopenia ranges from mild (50 000-100 000 platelets/μL), to severe (20 000 to <50 000/μL), to profound (<20 000/μL). Profound thrombocytopenia appears to occur in <1% of patients receiving their first course of therapy. Thrombocytopenia can be either acute (<24 hours) or delayed (up to ~14 days). Both hemorrhagic and thrombotic complications have been reported in association with thrombocytopenia. Diagnosis requires exclusion of pseudothrombocytopenia and heparin-induced thrombocytopenia. Therapy based on the severity of thrombocytopenia and symptoms may include drug withdrawals and treatment with steroids, intravenous IgG, and platelet transfusions. Abciximab-associated thrombocytopenia is most common and due to either preformed antibodies or antibodies induced in response to abciximab (delayed). Readministration of abciximab is associated with increased risk of thrombocytopenia. Evidence also supports an immune basis for thrombocytopenia associated with the 2 small molecule GPIs. The latter bind αIIbβ3 like the natural ligands and thus induce the receptor to undergo major conformational changes that potentially create neoepitopes. Thrombocytopenia associated with these drugs is also immune-mediated, with antibodies recognizing the αIIbβ3 receptor only in the presence of the drug. It is unclear whether the antibody binding depends on the conformational change and whether the drug contributes directly to the epitope. Zalunfiban, a second-generation subcutaneous small molecule GPI, does not induce the conformational changes; therefore, data from studies of zalunfiban will provide information on the contribution of the conformational changes to the development of GPI-associated thrombocytopenia.

Prepercutaneous coronary intervention Zalunfiban dose-response relationship to target vessel blood flow at initial angiogram in st-elevation myocardial infarction - A post hoc analysis of the cel-02 phase IIa study

BACKGROUND

Zalunfiban (RUC-4) is a novel, subcutaneously administered glycoprotein IIb/IIIa inhibitor (GPI) designed for prehospital treatment to initiate reperfusion in the infarct-related artery (IRA) before primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction (STEMI). Since GPIs have been reported to rapidly reperfuse IRAs, we assessed whether there was a dose-dependent relationship between zalunfiban treatment and angiographic reperfusion indices and thrombus grade of the IRA at initial angiogram in patients with STEMI.

METHODS

This was a post hoc analysis from the open-label Phase IIa study that investigated the pharmacodynamics, pharmacokinetics, and tolerability of three doses of zalunfiban - 0.075, 0.090 and 0.110 mg/kg - in STEMI patients. This analysis explored dose-dependent associations between zalunfiban and three angiographic indices of the IRA, namely coronary and myocardial blood flow and thrombus burden. Zalunfiban was administered in the cardiac catheterization laboratory prior to vascular access, ∼10 to 15 minutes before the initial angiogram. All angiographic data were analyzed by a blinded, independent, core laboratory.

RESULTS

Twentyfour out of 27 STEMI patients were evaluable for angiographic analysis (0.075 mg/kg [n=7], 0.090 mg/kg [n=9], and 0.110 mg/kg [n=8]). TIMI flow grade 2 or 3 was seen in 1/7 patients receiving zalunfiban at 0.075 mg/kg, in 6/9 patients receiving 0.090 mg/kg, and in 7/8 patients receiving 0.110 mg/kg (ptrend = 0.004). A similar trend was observed based on TIMI flow grade 3. Myocardial perfusion was also related to zalunfiban dose (ptrend = 0.005) as reflected by more frequent TIMI myocardial perfusion grade 3. Consistent with the dose-dependent trends in greater coronary and myocardial perfusion, TIMI thrombus ≥4 grade was inversely related to zalunfiban dose (ptrend = 0.02).

CONCLUSION

This post hoc analysis found that higher doses of zalunfiban administered in the cardiac catheterization lab prior to vascular access were associated with greater coronary and myocardial perfusion, and lower thrombus burden at initial angiogram in patients with STEMI undergoing primary percutaneous coronary intervention.

Current and Future Insights for Optimizing Antithrombotic Therapy to Reduce the Burden of Cardiovascular Ischemic Events in Patients with Acute Coronary Syndrome

The pharmacological treatment strategies for acute coronary syndrome (ACS) in recent years are constantly evolving to develop more potent antithrombotic agents, as reflected by the introduction of more novel P2Y₁₂ receptor inhibitors and anticoagulants to reduce the ischemic risk among ACS patients. Despite the substantial improvements in the current antithrombotic regimen, a noticeable number of ACS patients continue to experience ischemic events. Providing effective ischemic risk reduction while balancing bleeding risk remains a clinical challenge. This updated review discusses the currently approved and widely used antithrombotic agents and explores newer antithrombotic treatment strategies under development for the initial phase of ACS.

Pre-Hospital Antiplatelet Therapy for STEMI Patients Undergoing Primary Percutaneous Coronary Intervention: What We Know and What Lies Ahead

Early recanalization of the infarct-related artery to achieve myocardial reperfusion is the primary therapeutic goal in patients with ST-elevation myocardial infarction (STEMI). To decrease the duration of ischaemia, continuous efforts have been made to improve pre-hospital treatment and to target the early period after symptom onset. In this period the platelet content of the fresh coronary thrombus is maximal and the thrombi are dynamic, and thus more susceptible to powerful antiplatelet agents. There have been substantial advances in antiplatelet therapy in the last three decades with several classes of oral and intravenous antiplatelet agents with different therapeutic targets, pharmacokinetics, and pharmacodynamic properties. New parenteral drugs achieve immediate inhibition of platelet aggregation, and fast and easy methods of administration may create the opportunity to bridge the initial gap in platelet inhibition observed with oral P2Y12 inhibitors. Moreover, potential future management of STEMI could directly involve patients in the process of care with self-administered antiplatelet agents designed to achieve rapid reperfusion. However, the potential anti-ischaemic benefits of potent antiplatelet agents will need to be balanced against their risk of increased bleeding. This study presents a comprehensive and updated review of pre-hospital antiplatelet therapy among STEMI patients undergoing primary percutaneous intervention and explores new therapies under development.

Application of Auxiliary VerifyNow Point-of-Care Assays to Assess the Pharmacodynamics of RUC-4, a Novel αIIbβ3 Receptor Antagonist

Introduction  Prehospital therapy of ST-elevation myocardial infarction (STEMI) with αIIbβ3 antagonists improves clinical outcomes, but they are difficult to use in prehospital settings. RUC-4 is a novel αIIbβ3 antagonist being developed for prehospital therapy of STEMI that rapidly achieves high-grade platelet inhibition after subcutaneous administration. Standard light transmission aggregometry (LTA) is difficult to perform during STEMI, so we applied VerifyNow (VN) assays to assess the pharmacodynamics of RUC-4 relative to aspirin and ticagrelor.

Methods  Blood from healthy volunteers was anticoagulated with phenylalanyl-prolyl-arginyl chloromethyl ketone (PPACK) or sodium citrate, treated in vitro with RUC-4, aspirin, and/or ticagrelor, and tested with the VN ADP + PGE ₁ , iso-TRAP, and base channel (high concentration iso-TRAP + PAR-4 agonist) assays. The results were correlated with both ADP (20 µM)-induced LTA and flow cytometry measurement of receptor occupancy and data from individuals treated in vivo with RUC-4.

Results  RUC-4 inhibited all three VN assays, aspirin did not affect the assays, and ticagrelor markedly inhibited the ADP + PGE ₁ assay, slightly inhibited the iso-TRAP assay, and did not inhibit the base channel assay. RUC-4's antiplatelet effects were potentiated in citrate compared with PPACK. Cut-off values were determined to correlate the results of the VN iso-TRAP and base channel assays with 80% inhibition of LTA.

Conclusion  The VN assays can differentiate the early potent anti-αIIbβ3 effects of RUC-4 from delayed effects of P2Y12 antagonists in the presence of aspirin. These pharmacodynamic assays can help guide the clinical development of RUC-4 and potentially be used to monitor RUC-4's effects in clinical practice.

Pharmacokinetics, pharmacodynamics, and tolerability of subcutaneous administration of a novel glycoprotein IIb/IIIa inhibitor, RUC-4, in patients with ST-segment elevation myocardial infarction

BACKGROUND

Pre-hospital platelet inhibition in patients with ST-segment elevation myocardial infarction (STEMI) may improve outcomes. RUC-4 is a novel, second-generation glycoprotein IIb/IIIa inhibitor designed for first-point-of-medical-contact treatment for STEMI by subcutaneous injection.

AIMS

The open-label, phase 2A, CEL-02 trial aimed to assess the pharmacodynamics (PD), pharmacokinetics (PK), and tolerability of RUC-4 in STEMI patients undergoing primary PCI (pPCI).

METHODS

A total of 27 STEMI patients received a weight-adjusted subcutaneous injection of RUC-4 before pPCI in escalating doses (0.075 mg/kg [n=8], 0.090 mg/kg [n=9], or 0.110 mg/kg [n=10]).

RESULTS

The primary PD endpoint of high-grade (≥77%) inhibition of the VerifyNow iso-TRAP assay at 15 minutes was met in 3/8, 7/8, and 7/8 patients in the three cohorts with a dose-response relationship (mean inhibition [min - max] of 77.5% [65.7%-90.6%], 87.5% [73.8%-93.1%], and 91.7% [76.4%-99.3%], respectively; ptrend=0.002). Fifty percent (50%) inhibition remained after 89.1 (38.0-129.7), 104.2 (17.6-190.8), and 112.4 (19.7-205.0) minutes. Injection site reactions or bruising were observed in 1 (4%) and 11 (41%) patients, respectively. Mild access-site haematomas occurred in 6 (22%), and severe access-site haematomas occurred in 2 patients (7%). No thrombocytopaenia was observed within 72 hours post dose.

CONCLUSIONS

In patients with STEMI, a single subcutaneous dose of RUC-4 at 0.075, 0.090, and 0.110 mg/kg showed dose-response high-grade inhibition of platelet function within 15 minutes.

First Human Use of RUC-4: A Nonactivating Second-Generation Small-Molecule Platelet Glycoprotein IIb/IIIa (Integrin αIIbβ3) Inhibitor Designed for Subcutaneous Point-of-Care Treatment of ST-Segment-Elevation Myocardial Infarction

Background Despite reductions in door-to-balloon times for primary coronary intervention, mortality from ST-segment-elevation myocardial infarction has plateaued. Early pre-primary coronary intervention treatment of ST-segment-elevation myocardial infarction with glycoprotein IIb/IIIa inhibitors improves pre-primary coronary intervention coronary flow, limits infarct size, and improves survival. We report the first human use of a novel glycoprotein IIb/IIIa inhibitor designed for subcutaneous first point-of-care ST-segment-elevation myocardial infarction treatment. Methods and Results Healthy volunteers and patients with stable coronary artery disease receiving aspirin received escalating doses of RUC-4 or placebo in a sentinel-dose, randomized, blinded fashion. Inhibition of platelet aggregation (IPA) to ADP (20 μmol/L), RUC-4 blood levels, laboratory evaluations, and clinical assessments were made through 24 hours and at 7 days. Doses were increased until reaching the biologically effective dose (the dose producing ≥80% IPA within 15 minutes, with return toward baseline within 4 hours). In healthy volunteers, 15 minutes after subcutaneous injection, mean±SD IPA was 6.9%+7.1% after placebo and 71.8%±15.0% at 0.05 mg/kg (n=6) and 84.7%±16.7% at 0.075 mg/kg (n=6) after RUC-4. IPA diminished over 90 to 120 minutes. In patients with coronary artery disease, 15 minutes after subcutaneous injection of placebo or 0.04 mg/kg (n=2), 0.05 mg/kg (n=6), and 0.075 mg/kg (n=18) of RUC-4, IPA was 14.6%±11.7%, 53.6%±17.0%, 76.9%±10.6%, and 88.9%±12.7%, respectively. RUC-4 blood levels correlated with IPA. Aspirin did not affect IPA or RUC-4 blood levels. Platelet counts were stable and no serious adverse events, bleeding, or injection site reactions were observed. Conclusions RUC-4 provides rapid, high-grade, limited-duration platelet inhibition following subcutaneous administration that appears to be safe and well tolerated. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NTC03844191.

Preclinical Studies of RUC-4, a Novel Platelet αIIbβ3 Antagonist, in Non-Human Primates and With Human Platelets

Introduction

We are developing the novel αIIbβ3 antagonist, RUC-4, for subcutaneously (SC)-administered first-point-of-medical-contact treatment for ST Segment Elevated Myocardial Infarction (STEMI).

Methods

We studied the: 1. pharmacokinetics (PK) of RUC-4 at 1.0, 1.93, and 3.86 mg/kg IV, IM, and SC in non-human primates (NHPs); 2. impact of aspirin on RUC-4 IC₅₀ in human platelet-rich plasma (PRP); 3. effect of different anticoagulants on the RUC-4 IC₅₀ in human PRP; and 4. relationship between αIIbβ3 receptor blockade by RUC-4 and inhibition of ADP-induced platelet aggregation.

Results

1. All doses of RUC-4 were well tolerated, but animals demonstrated variable temporary bruising. IM and SC RUC-4 reached dose-dependent peak levels within 5-15 min, with T_½ s between 0.28 and 0.56 hrs. Platelet aggregation studies in NHPs receiving IM RUC-4 demonstrated >80% inhibition of the initial slope of ADP-induced aggregation with all 3 doses 30 minutes post-dosing, with subsequent dose-dependent loss of inhibition over 4-5 hours. 2. The RUC-4 IC₅₀ for ADP-induced platelet aggregation was unaffected by aspirin treatment (40±9 nM vs. 37±5 nM; p=0.39). 3. The RUC-4 IC₅₀ was significantly higher in PRP prepared from PPACK-anticoagulated blood compared to citrate-anticoagulated blood using either TRAP (122±17 vs. 66±25 nM; p=0.05; n=4) or ADP (102±22 vs. 54±13; p<0.001; n=5). 4. There was a close correspondence between receptor blockade and inhibition of ADP-induced platelet aggregation, with aggregation inhibition beginning with ~40% receptor blockade and becoming nearly complete at >80% receptor blockade.

Discussion

Based on these results and others, RUC-4 has now progressed to formal preclinical toxicology studies.

An αIIbβ3- and phosphatidylserine (PS)-binding recombinant fusion protein promotes PS-dependent anticoagulation and integrin-dependent antithrombosis

Blood platelets are required for normal wound healing, but they are also involved in thrombotic diseases, which are usually managed with anticoagulant drugs. Here, using genetic engineering, we coupled the disintegrin protein echistatin, which specifically binds to the platelet integrin α_IIbβ₃ receptor, to annexin V, which binds platelet membrane-associated phosphatidylserine (PS), to create the bifunctional antithrombotic molecule recombinant echistatin-annexin V fusion protein (r-EchAV). Lipid binding and plasma coagulation studies revealed that r-EchAV dose-dependently binds PS and delays plasma clotting time. Moreover, r-EchAV inhibited ADP-induced platelet aggregation in a dose-dependent manner and exhibited potent antiplatelet aggregation effects. r-EchAV significantly prolonged activated partial thromboplastin time, suggesting that it primarily affects the in vivo coagulation pathway. Flow cytometry results indicated that r-EchAV could effectively bind to the platelet α_IIbβ₃ receptor, indicating that r-EchAV retains echistatin's receptor-recognition region. In vivo experiments in mice disclosed that r-EchAV significantly prolongs bleeding time, indicating a significant anticoagulant effect in vivo resulting from the joint binding of r-EchAV to both PS and the α_IIbβ₃ receptor. We also report optimization of the r-EchAV production steps and its purification for high purity and yield. Our findings indicate that r-EchAV retains the active structural regions of echistatin and annexin V and that the whole molecule exhibits multitarget-binding ability arising from the dual functions of echistatin and annexin V. Therefore, r-EchAV represents a new class of anticoagulant that specifically targets the anionic membrane-associated coagulation enzyme complexes at thrombogenesis sites and may be a potentially useful antithrombotic agent.

Thrombus aspirated from patients with ST-elevation myocardial infarction: Clinical and angiographic outcomes

Objective

To investigate differences in clinical and angiographic outcomes between patients with acute myocardial infarction with red and white thrombi.

Methods

A total of 137 patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary interventions were included. Thrombus material was classified as white or red based on its pathology. Information on characteristics of thrombi was available for 97 (70.8%) patients.

Results

The total ischaemic time was significantly longer in the red thrombus group compared with the white thrombus group. The incidence of major adverse cardiovascular events in hospital was higher in the red thrombus group than in the white thrombus group (15.6% vs 0%). Multivariable logistic analysis showed that the total ischaemic time was the only predictor of thrombus composition (odds ratio 1.353; 95% confidence interval 1.003, 1.826).

Conclusion

Red thrombi were present in nearly two-thirds of cases, and were associated with a longer ischaemic time and higher incidence of major adverse cardiovascular events in hospital.

Clinical significance of no-reflow in different stages of primary angioplasty among patients with acute myocardial infarctions

Background:

The coronary no-reflow (NR) phenomenon, which is associated with poor clinical outcomes, is usually referred to as a post-percutaneous coronary intervention (PCI) state. NR can occur in different stages of the PCI procedure, not only including the post-stenting stage, but from balloon pre-dilation to pre-stenting. The clinical significance of NR in the different stages of the PCI procedure is unclear. The purpose of the current study was to analyze the clinical and angiographic characteristics, the prognosis for NR patients in the aforementioned two stages and to determine the predictors of NR in the early stage.

Methods:

Between January 2009 and December 2013, a total of 420 consecutive patients with ST-segment elevation myocardial infarction (STEMI) underwent primary PCI. Sixty-three patients (15%) with NR constituted the study population. The patients were divided into an early NR group and a subsequent NR group. The clinical and angiographic findings were compared between the two groups. Multivariate logistic regression was used to determine the predictors for early NR. The long-term clinical outcomes after PCI were analyzed.

Results:

Regarding the baseline characteristics, we identified that the early NR group had statistically significant effects on the higher percentage of diabetes mellitus (42.9% vs. 20%), lower admission systolic blood pressure (SBP) (102.2±8.3 mmHg vs. 110.5±7.6 mmHg), higher percentage of Killip classification III (71.4% vs. 45.7%,) and longer reperfusion time (7.1±2.3 h vs. 5.88±2.2 h) compared to the subsequent NR group. There were significant differences between the two groups with respect to the percentage of initial thrombolysis in myocardial infarction (TIMI) flow 0/1 (64.3% vs. 37.1%), target lesion length (31.4±13.6 mm vs. 20.5±17.3 mm) and thrombus score ⩾4 (67.9% vs. 42.9%; p<0.05 for all). Multiple stepwise logistic regression analysis indicated that an admission SBP <100 mmHg (OR=4.580; 95% CI=1.385–15.150; p=0.0130), reperfusion time ⩾6 h (OR=4.978; 95% CI=1.468–16.882; p=0.010) and a thrombus score ⩾4 (OR=2.708; 95% CI=0.833–8.799; p=0.008) were the independent determinants of the early NR. During a 1-year follow-up, the all-cause mortality and overall major adverse cardiac events (MACEs) in the early NR group occurred significantly more often than in the subsequent NR group (28.6% vs. 5.7% and 35.7% vs. 14.3%, respectively, p <0.05). The early NR group had a lower left ventricular ejection fraction (LVEF) (42.5±4.7 vs. 47.8±3.5, p <0.001) and a larger left ventricular end diastolic diameter (LVEDD) (56.0±4.0 vs. 51.5 ±4.7, p=0.001) at the end of the follow-up.

Conclusion:

Early NR patients during primary PCI have more severe baseline clinical and angiographic characteristics, as well as a poorer long-term prognosis.

Current state and novel approaches of antiplatelet therapy

An unresolved problem with clinical use of antiplatelet therapy is that a significant number of individuals either still get thrombosis or run the risk of life-threatening bleeding. Antiplatelet drugs are widely used clinically, either chronically for people at risk of athero/thrombotic disease or to prevent thrombus formation during surgery. However, a subpopulation may be resistant to standard doses, while the platelet targets of these drugs are also critical for the normal hemostatic function of platelets. In this review, we will briefly examine current antiplatelet therapy and existing targets while focusing on new potential approaches for antiplatelet therapy and improved monitoring of effects on platelet reactivity in individuals, ultimately to improve antithrombosis with minimal bleeding. Primary platelet adhesion-signaling receptors, glycoprotein (GP)Ib-IX-V and GPVI, that bind von Willebrand factor/collagen and other prothrombotic factors are not targeted by drugs in clinical use, but they are of particular interest because of their key role in thrombus formation at pathological shear.

RUC-4: a novel αIIbβ3 antagonist for prehospital therapy of myocardial infarction

OBJECTIVE

Treatment of myocardial infarction within the first 1 to 2 hours with a thrombolytic agent, percutaneous coronary intervention, or an αIIbβ3 antagonist decreases mortality and the later development of heart failure. We previously reported on a novel small molecule αIIbβ3 antagonist, RUC-2, that has a unique mechanism of action. We have now developed a more potent and more soluble congener of RUC-2, RUC-4, designed to be easily administered intramuscularly by autoinjector to facilitate its use in the prehospital setting. Here, we report the properties of RUC-4 and the antiplatelet and antithrombotic effects of RUC-2 and RUC-4 in animal models.

APPROACH AND RESULTS

RUC-4 was ≈ 20% more potent than RUC-2 in inhibiting human ADP-induced platelet aggregation and much more soluble in aqueous solutions (60-80 mg/mL). It shared RUC-2's specificity for αIIbβ3 versus αVβ3, did not prime the receptor to bind fibrinogen, or induce changes in β3 identified by a conformation-specific monoclonal antibody. Both RUC-2 and RUC-4 prevented FeCl3-induced thrombotic occlusion of the carotid artery in mice and decreased microvascular thrombi in response to laser injury produced by human platelets infused into transgenic mice containing a mutated von Willebrand factor that reacts with human but not mouse platelets. Intramuscular injection of RUC-4 in nonhuman primates at 1.9 and 3.85 mg/kg led to complete inhibition of platelet aggregation within 15 minutes, with dose-dependent return of platelet aggregation after 4.5 to 24 hours.

CONCLUSIONS

RUC-4 has favorable biochemical, pharmacokinetic, pharmacodynamic, antithrombotic, and solubility properties as a prehospital therapy of myocardial infarction, but the possibility of increased bleeding with therapeutic doses remains to be evaluated.

Efficacy of pre-hospital use of glycoprotein IIb/IIIa inhibitors in ST-segment elevation myocardial infarction before mechanical reperfusion in a rapid-transfer network (from the Acute Myocardial Infarction Registry of Brittany)

Previous studies investigating prehospital use of glycoprotein IIb/IIIa inhibitors (GPIs) in patients with ST-segment elevation myocardial infarction reached conflicting conclusions. The benefit of this strategy in addition to in-ambulance loading of dual-antiplatelet therapy remains controversial. The aim of this study was to analyze data from a prospective registry of patients with ST-segment elevation myocardial infarctions admitted <24 hours after symptom onset (July 2006 to May 2012). A total of 2,052 patients managed in a physician-staffed mobile intensive care unit (MICU)<12 hours after symptom onset and scheduled for primary percutaneous coronary intervention (PPCI) were retrospectively included. Patients who received GPIs in the MICU were compared with those who did not. The primary end point was infarct-related artery patency, defined as pre-PPCI Thrombolysis In Myocardial Infarction (TIMI) flow grade 3. GPIs were administered in the MICU to 737 patients (36%), including 430<2 hours after symptom onset, and 1,315 patients (64%) did not received prehospital GPIs. Pre-PPCI TIMI flow grade 3 rate was lower in patients treated in the MICU (17.2% vs 21.3%, p=0.03) because of patients treated >2 hours after symptom onset, of whom only 12.7% reached the primary end point. There was no significant difference between groups in the rate of in-hospital major adverse cardiac events. In conclusion, prehospital GPI use in patients with ST-segment elevation myocardial infarctions<12 hours after symptom onset scheduled for PPCI neither improved pre-PPCI infarct-related artery patency nor reduced in-hospital major adverse cardiac events.

A novel class of ion displacement ligands as antagonists of the αIIbβ3 receptor that limit conformational reorganization of the receptor

A collection of αIIbβ3 integrin receptor antagonists possessing a unique MIDAS metal ion displacement mechanism of action is presented. Insight into these agents' structure-activity relationships, binding modality, and pharmacokinetic and pharmacodynamic profiles highlight the potential of these small molecule ion displacement ligands as attractive candidates for clinical development.