Kengreal

8.1        Pregnancy

Risk Summary

There are no available data on cangrelor use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Untreated myocardial infarction can be fatal to the pregnant women and fetus (see Clinical Considerations).

In animal reproduction studies, continuous infusion of cangrelor in pregnant rats and rabbits throughout organogenesis at dose approximately 2-times the maximum recommended human dose (MRHD) did not result in fetal malformations (see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Clinical Considerations

Disease-associated maternal and/or embryo/fetal risk

Myocardial infarction is a medical emergency in pregnancy which can be fatal to the pregnant woman and fetus if left untreated. Life-sustaining therapy for the pregnant woman should not be withheld due to potential concerns regarding the effects of cangrelor on the fetus.

Labor or delivery

Cangrelor use during labor and delivery may increase the risk for maternal bleeding and hemorrhage. Performance of neuraxial blockade procedures is not advised during cangrelor use due to potential risk of spinal hematoma. When possible, discontinue cangrelor 1 hour prior to labor, delivery, or neuraxial blockade [see Clinical  Pharmacology ].

Data

Animal Data

A prenatal and postnatal development study in female rats demonstrated a slight increase in the incidence of maternal mortality in dams treated at doses up to 30 mcg/kg/min (approximately 7.5 times the MRHD) cangrelor continuous infusion from Day 6 of gestation up to Day 23 post-partum. Pregnancy rates, gestation index, length of gestation, numbers of live, dead and malformed pups, sex ratio, live birth index, and lactation of the maternal animals were unaffected.

Cangrelor administered at dose levels of ≥ 3 mcg/kg/min in pregnant rats from Day 6 to 17 post-coitum resulted in dose-related fetal growth retardation characterized by increased incidences of incomplete ossification and unossified hind limb metatarsals.

An embryo-fetal development study in rabbits administered 4, 12, or 36 mcg/kg/min cangrelor continuous IV infusion from Day 6 to Day 19 post-coitum resulted in increased incidences of abortion and intrauterine losses at ≥12 mcg/kg/min (3 times the MRHD). Fetal growth retardation occurred at 36 mcg/kg/min (9 times the MRHD) and was characterized by decreased fetal weights, slight reduction in ossification, and a slight increase in skeletal variants.

Cangrelor did not produce malformations in either the rat or rabbit embryo-fetal development studies and is not considered to be a teratogen.

8.2       Lactation

Risk Summary

There are no data on the presence of cangrelor in human milk or animal milk, the effects on the breastfed infant, or the effects on milk production. However, due to its short-half life, cangrelor exposure is expected to be very low in the breastfed infant.

8.4        Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

8.5        Geriatric Use

In CHAMPION PHOENIX, 18% of patients were ≥75 years. No overall differences in safety or effectiveness were observed between these patients and those patients <75 years [see Clinical Studies ( 14.1)].

8.6        Renal Impairment

No dosage adjustment is required for patients with mild, moderate, or severe renal impairment [see Clinical Pharmacology ( 12.3)].

8.7        Hepatic Impairment

KENGREAL has not been studied in patients with hepatic impairment. However, the metabolism of KENGREAL is not dependent of hepatic function, so dosage adjustment is not required for patients with hepatic impairment [see Clinical Pharmacology ( 12.3)].

12.1        Mechanism of Action

Cangrelor is a direct P2Y12 platelet receptor inhibitor that blocks ADP-induced platelet activation and aggregation. Cangrelor binds selectively and reversibly to the P2Y12 receptor to prevent further signaling and platelet activation.

12.2        Pharmacodynamics

Cangrelor inhibits activation and aggregation of platelets. After administration of a 30 mcg/kg IV bolus followed by a 4 mcg/kg/min IV infusion, platelet inhibition occurs within 2 minutes.

Figure 2 shows the effect on platelet activity, and its relation to cangrelor plasma concentration, of administering a 30 mcg/kg IV bolus, followed by a 1-hour 4 mcg/kg/min IV infusion, of cangrelor. The anti-platelet effect is maintained for the duration of the infusion. After discontinuation of the infusion, the anti-platelet effect decreases rapidly and platelet function returns to normal within 1 hour.

Figure 2: Cangrelor PD Characteristics

12.3        Pharmacokinetics

KENGREAL administered intravenously has linear pharmacokinetics in both healthy volunteers and patients. KENGREAL is rapidly distributed and metabolized, reaching Cmax within 2 minutes after administration of an intravenous bolus followed by infusion.

Distribution

In a study in healthy volunteers, KENGREAL administration at a dose of 30 mcg/kg bolus plus 4 mcg/kg/min showed a volume of distribution of 3.9 L. Plasma protein binding of KENGREAL is about 97-98%.

Metabolism

KENGREAL is deactivated rapidly in the circulation by dephosphorylation to its primary metabolite, a nucleoside, which has negligible anti-platelet activity. KENGREAL’s metabolism is independent of hepatic function and it does not interfere with other drugs metabolized by hepatic enzymes.

Elimination

Following IV administration of [3H] KENGREAL 58% of radioactivity was recovered in urine. The remaining 35% of radioactivity was in feces, presumably following biliary excretion. The average elimination half-life of KENGREAL is about 3-6 minutes.

Specific Populations

KENGREAL pharmacokinetics are not affected by sex, age, renal status or hepatic function. No dose adjustment is needed for these factors [see Use in Specific Populations ( 8)].

Weight

Although weight was a significant covariate for PK with higher clearance in heavier patients, the impact of weight on drug exposure is accounted by the use of weight-based dosing.

Drug-Drug Interactions

Co-administration of cangrelor with unfractionated heparin, aspirin, and nitroglycerin was formally studied in healthy subjects, with no evidence of an effect on the PK/PD of cangrelor.

In clinical trials cangrelor has been co-administered with bivalirudin, low molecular weight heparin, clopidogrel, prasugrel, and ticagrelor without clinically detectable interactions.

The expected antiplatelet effect of a 600 mg loading dose of clopidogrel or a 60 mg loading dose of prasugrel was blocked when clopidogrel or prasugrel was administered during a cangrelor infusion [see Drug Interactions ( 7.1)].

In contrast, the antiplatelet effect of a 180 mg ticagrelor loading dose was not altered significantly when ticagrelor was administered during cangrelor infusion [see Drug Interactions ( 7.1)].

Figure 3: Inhibition (Mean) of 20 µM ADP-induced Platelet Aggregation (IPA) Measured by Light Transmission Aggregometry after Cangrelor 30 mcg/kg Bolus and 120-minute 4 mcg/kg Infusion with Transition to Other Oral P2Y12 Platelet Inhibitors.

As shown in Figure 3, discontinuation of cangrelor infusion, followed by administration of the irreversible P2Y12 platelet inhibitors clopidogrel or prasugrel led to a 1-hour decrease in IPA followed by an increase in inhibition of platelet aggregation beginning at about one hour. This time course of platelet inhibition reflects the pharmacokinetics of cangrelor (offset) followed by the absorption and metabolism of clopidogrel and prasugrel to active metabolites (onset). Administration of ticagrelor, a reversible P2Y12 platelet inhibitor, during the cangrelor infusion led to minimal decrease in platelet inhibition for approximately 0.5 hour following discontinuation of the cangrelor infusion. Administering ticagrelor during cangrelor infusion does not attenuate the anti-platelet effect of ticagrelor.

In vitro studies suggest that neither cangrelor nor its major metabolites inhibit the activity of the hepatic CYP isoenzymes at therapeutic concentrations. Therefore, cangrelor administration is not expected to interfere with the hepatic metabolism of other concomitantly administered therapeutic agents.

13.1        Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

No carcinogenicity studies were conducted.

Mutagenesis

Cangrelor was non-mutagenic and non-clastogenic in genetic toxicology studies, including in vitro bacterial gene mutation assay, mouse lymphoma thymidine kinase assay, chromosome aberration assay in human peripheral lymphocytes, and in vivo bone marrow micronucleus assay in mice.

Impairment of Fertility

Cangrelor had no significant effect on male or female rats fertility treated by continuous infusion for 28 days, or on early embryonic development at steady state plasma concentration (Css) of approximately the same as that achieved in the PCI setting at the MRHD.

14.1        CHAMPION PHOENIX Trial

The CHAMPION PHOENIX trial was intended to test whether faster platelet inhibition with cangrelor at the time of PCI would reduce the rate of periprocedural thrombotic events compared to a drug with a slower antiplatelet effect, clopidogrel, given at about the time of PCI. It was a randomized, double-blind study in which patients with coronary artery disease (stable angina, UA/NSTEMI, STEMI) requiring PCI and receiving standard therapy including aspirin and heparin or bivalirudin were randomized 1:1 to KENGREAL (n=5472) or to clopidogrel 300 or 600 mg (n=5470). Patients who had already taken an oral P2Y12 platelet inhibitor were not eligible to enroll. Patients administered glycoprotein IIb/IIIa inhibitors (GPI) or for whom GPI use was planned were also not eligible to enroll. PHOENIX was thus a study of people undergoing PCI who had not been previously treated with anti-platelet therapy other than aspirin.

The primary outcome measure was the first occurrence of any one of the composite endpoint of all-cause mortality, myocardial infarction (MI), ischemia-driven revascularization (IDR), and stent thrombosis (ST) within 48 hours after randomization.

KENGREAL was administered as 30 mcg/kg bolus followed by 4 mcg/kg/min infusion for 2 to 4 hours. Clopidogrel 600 mg was administered immediately at the end of the KENGREAL infusion in patients randomized to KENGREAL. Clopidogrel 300 mg or 600 mg was administered shortly before PCI or shortly afterward, in patients randomized to clopidogrel.

KENGREAL significantly reduced the occurrence of primary composite endpoint events compared to clopidogrel (relative risk reduction [RRR] 22%). Most of the effect was a reduction in post-procedural MIs detected solely by elevations in CK-MB (type 4a MI). KENGREAL did not reduce the risk of death. Table 2 shows the study results for the primary composite endpoint and the contribution of each component to the primary endpoint.

Note: if a subject had more than one event at 48 hours, then worst outcome counted (death >MI >IDR >ST)

aThe mITT population is all randomized subjects who received at least one dose of study drug and underwent the index PCI procedure

b Based on logistic model adjusted for loading dose and baseline patient status for primary endpoint

A supplementary analysis was also performed omitting two subcomponent events of the primary endpoint that were of lesser clinical significance: intraprocedural stent thrombosis (defined as a new or increasing thrombus within or adjacent to a deployed stent occurring during the index PCI procedure), and myocardial infarction with less than a 10-fold increase in CK-MB, or with less than a 5-fold increase in CK-MB in the presence of new Q waves or new left bundle branch block (LBBB). These results are shown in Table 3.

Note: if a subject had more than one event at 48 hours, then worst outcome counted (death >SCAI-MI >IDR >ARC-ST)

aSCAI MI: CK-MB ≥10X ULN, or CK-MB ≥5X ULN with new Q waves or new LBBB

bARC-ST defined according to the ARC definition [Cutlip et al. 2007]

The effect of KENGREAL appeared to be consistent in a variety of pre-specified and other clinically important subgroups (see Figure 4).

Figure 4: CHAMPION PHOENIX Study: Primary Efficacy Endpoint by Subgroup (mITT Populationa)

a The mITT population is all randomized subjects who received at least one dose of study drug and underwent the index PCI procedure.

Note: The figure above presents effects in various subgroups most of which are baseline characteristics and most of which were pre-specified (patient presentation and weight were not pre-specified subgroups). The 95% confidence limits that are shown do not take into account how many comparisons were made, nor do they reflect the effect of a particular factor after adjustment for all other factors. Apparent homogeneity or heterogeneity among groups should not be over-interpreted.

14.2        CHAMPION PCI and PLATFORM Trials

Two additional concurrent clinical trials of the effect of KENGREAL in patients undergoing percutaneous coronary intervention, CHAMPION PCI and CHAMPION PLATFORM were conducted and terminated early for futility. They were completed prior to the design and conduct of CHAMPION PHOENIX. The comparative characteristics and outcomes of each trial are shown in Table 4.