Prevention of venous thromboembolism with an oral factor Xa inhibitor, YM150, after total hip arthroplasty. A dose finding study (ONYX-2)

BACKGROUND

Anticoagulant prophylaxis substantially reduces the risk of venous thromboembolism (VTE) after major orthopedic surgery. The direct factor Xa inhibitor YM150 is currently under investigation for the prevention of VTE, stroke and ischemic vascular events in patients after orthopedic surgery, with atrial fibrillation and with acute coronary syndrome, respectively.

OBJECTIVES

To investigate the efficacy and safety of YM150 for the prevention of VTE following elective total hip arthroplasty.

PATIENTS/METHODS

Patients were randomized to postoperative, once-daily, oral YM150 (5, 10, 30, 60 or 120 mg) (double-blind) or preoperative subcutaneous (open label) enoxaparin (40 mg) for 5 weeks. The primary efficacy endpoint comprised VTE diagnosed by mandatory bilateral venography or verified symptomatic deep vein thrombosis (DVT) plus all deaths up to 9 days after surgery. The primary safety outcome was major bleeding up to 9 days after surgery.

RESULTS

Primary efficacy endpoint: of 1017 patients randomized, 960 patients were evaluable for safety and 729 patients for efficacy. A dose-related decrease in VTE incidence from YM150 5 to 60 mg (P = 0.0005) and from 5 to 120 mg (P = 0.0002) was found. The VTE incidence was 27.4%, 31.7%, 19.3%, 13.3% and 14.5% for 5, 10, 30, 60 and 120 mg YM150, respectively, and 18.9% for enoxaparin. Primary safety endpoint: there was one major bleed with YM150 (60 mg) and one with enoxaparin.

CONCLUSIONS

The oral direct FXa inhibitor YM150 demonstrated a significant dose response regarding efficacy. Doses from 30 to 120 mg had comparable efficacy to enoxaparin, without compromising safety regarding major bleeding events.

A dose escalation study of YM150, an oral direct factor Xa inhibitor, in the prevention of venous thromboembolism in elective primary hip replacement surgery

BACKGROUND

YM150, a new oral direct factor Xa inhibitor is used as prophylaxis for venous thromboembolism (VTE), a well-known risk after orthopaedic surgery.

OBJECTIVES

To assess the safety and efficacy of thromboprophylaxis with YM150 in a dose escalation study.

PATIENTS/METHODS

Patients (174) undergoing hip replacement surgery were randomized per cohort to oral once daily YM150 or subcutaneous enoxaparin (40 mg daily) in a 4:1 ratio for 7-10 days treatment. The YM150 doses were 3, 10, 30 and 60 mg by sequential four-dose escalation cohorts. The primary endpoint was major and/or clinically relevant non-major bleeding. The incidence of VTE was defined as a composite of verified symptomatic events and/or positive findings at bilateral venography on the last treatment day. An independent adjudication committee evaluated blindly the outcomes of the open-label study.

RESULTS

No major and three clinically relevant non-major bleeds were reported, 1 (2.9%; 95% CI, 0.1-15.1) in the 3 mg and 2 (5.7%; 95% CI, 1.0-18.8) in the 10 mg YM150 dose groups. Of 147 patients (84%) with an evaluable venogram, VTE was observed in 51.9% (95% CI, 31.9-71.4), 38.7% (95% CI, 22.6-57.0), 22.6% (95% CI, 9.7-39.4), and 18.5% (95% CI, 7.5-36.5) in the YM150 dose groups 3, 10, 30 and 60 mg, respectively. A significant YM150 dose-related trend in VTE incidence was found (P=0.006). VTE with enoxaparin was 38.7% (95% CI, 22.6-57.0).

CONCLUSIONS

YM150, 10-60 mg daily, starting 6-10 h after primary hip replacement, was shown to be safe, well tolerated and effective.

Increased survival with beta-blockers: importance of ancillary properties

To assess the relative importance of ancillary properties (ie, intrinsic sympathomimetic activity (ISA), beta 1-selectivity, membrane stabilizing activity, and lipophilicity) in the effect of beta-blockers on mortality, a meta-analysis of all available secondary and primary prevention trials was performed. Seventy-one trials evaluating the effect on mortality after myocardial infarction (MI) were identified. The overall relative risk (RR) of mortality during beta-blocker treatment versus placebo was 0.89 (95% confidence interval [CI] 0.84-0.93), with a trend according to time of intervention: very early intervention RR 0.94 (95% CI 0.87-1.01), early intervention RR 0.91 (95% CI 0.81-1.01), and late intervention RR 0.80 (95% CI 0.73-0.88). Results were similar or even more marked for the end points one-week mortality, reinfarction, and sudden death. beta 1-selectivity, lipophilicity, absence of membrane stabilizing property, and absence of ISA were associated with a greater risk reduction compared with beta-blockers with the opposite ancillary property. When the effect of the three most frequently used beta-blocking drugs (atenolol, metoprolol, and propranolol) were compared, the drug with the combination of ancillary properties showing the most pronounced beneficial effects (metoprolol) had the most marked effect on survival. A similar trend was observed when the five published primary prevention trials comparing beta-blockers and diuretics in patients with hypertension were considered, but the number of studies was too low to allow for definite conclusions. We conclude that beta-blockade after MI leads to a substantial reduction in mortality. The so-called 'class-effect' of beta-blockers, however, can be questioned, because ancillary properties appear to play an important role in the efficacy of these drugs.

Calcium antagonists, a useful additional therapy in treatment resistant hypertension: comparison of felodipine ER and nifedipine Retard by 24-h ambulatory blood pressure monitoring

OBJECTIVE

To compare the efficacy and tolerability of felodipine extended release (ER) 2.5 mg (F2.5) and 5 mg (F5) once daily with nifedipine Retard 10 mg (N20) and 20 mg (N40) twice daily as additional therapy in patients who remained hypertensive despite treatment with an ACE-inhibitor, beta-blocker or diuretic.

DESIGN AND METHODS

In a multicentre, double-blind parallel study, 61 men and 54 women, aged 35-75, with a supine diastolic blood pressure between 95 and 115 mmHg were randomised to treatment with F2.5, F5, N20 or N40 for 8 weeks, with optional doubling of the dose after 4 weeks. Blood pressure was measured at the office after 0, 4 and 8 weeks and by 24-h ambulatory monitoring (ABPM) after 0 and 4 weeks. Spontaneously reported adverse events and a subjective symptom assessment questionnaire were used for side-effect profiling.

RESULTS

Mean office systolic/diastolic blood pressure was clinically relevantly reduced in all treatment groups after 4 weeks by 8/7, 12/9, 11/9 and 18/11 mmHg for F2.5, F5, N20 and N40, respectively, and after 8 weeks (F2.5-5: 17/11 mmHg: F5-10: 18/14 mmHg; N20-40: 19/14 mmHg; N40-80: 25/14 mmHg) with no statistically significant differences between these groups. The lowest dose of felodipine (F2.5) was the least effective. After 4 weeks the ABPM showed consistent 24-h reductions in blood pressure (4/2; 8/5; 7/5; 10/6 mmHg, respectively) over 24 h for the felodipine ER 5 mg group only and for both nifedipine groups. No statistically significant difference between these groups was found. An office responder does not appear to be identical to an ambulatory one and vice versa. The adverse events, mostly oedema, flushing and headache, were dose-related.

CONCLUSIONS

Both felodipine ER and nifedipine Retard are effective "add-on' drugs in patients with monotherapy-resistant hypertension. The blood-pressure-lowering effect is dose-dependent and tolerability is inversely related to efficacy. The results emphasize the benefits of combining two agents with low doses.

Once daily felodipine in patients with primary Raynaud's phenomenon

The symptomatic effects of felodipine (Plendil) have been assessed in 10 patients with primary Raynaud's phenomenon in a single blind study. After 2 weeks on placebo, the patients were treated for 6 weeks with felodipine, the dose being titrated stepwise every 2 weeks, starting with 5 mg, and increasing to 10 mg and 20 mg once daily if symptoms persisted. After the drug period the patients received placebo for 2 weeks. Objective measurement by cold exposure finger plethysmography did not show any benefit of felodipine in the higher temperature range, taking 33 degrees C as reference point. However, when using 24 degrees C as the reference point, the area under the plethysmography versus temperature curve (AUC) for 5 mg felodipine were significantly larger than the initial placebo area. The AUC during recovery from cold exposure for the maximal accepted dose of felodipine was significantly larger than for the initial placebo period. Subjective judgement by the patients showed a significant reduction in the number of Raynaud attacks and a trend to a shorter duration of attacks with the maximal dose of felodipine. Two patients became free from attacks of Raynaud's phenomenon. Felodipine 10 mg once daily was well tolerated. It was regarded as the optimal dose to treat patients with Raynaud's symptoms.

Endralazine, a new peripheral vasodilator. Evaluation of safety and efficacy over a 3 year period

Nineteen out-patients with moderate to severe essential hypertension were treated daily for 3 years, with an average dose of 13 mg endralazine, a new peripheral vasodilator, in free combination with pindolol 3 x 5 mg. The blood pressure showed a statistically significant reduction from 172/110 mmHg to 154/92 mmHg after treatment for 3 years. Tachyphylaxis was not observed during the 3 years period. Oedema was the most frequent side-effect, but it disappeared spontaneously. No difference in efficacy and tolerance between slow and fast acetylators was found. Only 2 patients developed a weak positive antinuclear antibody titre, which disappeared spontaneously from one during continued treatment. No clinical evidence of a systemic lupus erythematosus-like syndrome was noted. It is concluded that the differences between endralazine and hydralazine in dosage and metabolism may explain the lower immunogenic activity of endralazine.