ORBACTIV Powder for solution for injection Ref.[10366] Active ingredients: Oritavancin

5.1 Coagulation Test Interference

ORBACTIV has been shown to artificially prolong aPTT for up to 120 hours, PT and INR for up to 12 hours, and activated clotting time (ACT) for up to 24 hours following administration of a single 1200 mg dose by binding to and preventing action of the phospholipid reagents commonly used in laboratory coagulation tests. ORBACTIV has also been shown to elevate D-dimer concentrations up to 72 hours after ORBACTIV administration.

For patients who require aPTT monitoring within 120 hours of ORBACTIV dosing, a non-phospholipid dependent coagulation test such as a Factor Xa (chromogenic) assay or an alternative anticoagulant not requiring aPTT monitoring may be considered [see Contraindications (4.1) and Drug Interactions (7.2)].

ORBACTIV has no effect on the coagulation system in vivo.

5.2 Hypersensitivity

Serious hypersensitivity reactions, including anaphylaxis, have been reported with the use of ORBACTIV. If an acute hypersensitivity reaction occurs during ORBACTIV infusion, discontinue ORBACTIV immediately and institute appropriate supportive care. Before using ORBACTIV, inquire carefully about previous hypersensitivity reactions to glycopeptides. Due to the possibility of cross-sensitivity, carefully monitor for signs of hypersensitivity during ORBACTIV infusion in patients with a history of glycopeptide allergy. In the Phase 3 ABSSSI clinical trials, the median onset of hypersensitivity reactions in ORBACTIV-treated patients was 1.2 days and the median duration of these reactions was 2.4 days [see Adverse Reactions (6.1)].

5.3 Infusion Related Reactions

ORBACTIV is administered as a single dose by intravenous infusion, using a total infusion time of 3 hours to minimize the risk of infusion-related reactions. Infusion related reactions have been reported with the glycopeptide class of antimicrobial agents, including ORBACTIV, that resemble “Red-man Syndrome”, including flushing of the upper body, urticaria, pruritus and/or rash [see Adverse Reactions (6.1)]. Infusion reactions characterized by chest pain, back pain, chills and tremor have been observed with the use of ORBACTIV, including after the administration of more than one dose of ORBACTIV during a single course of therapy. Stopping or slowing the infusion may result in cessation of these reactions. The safety and effectiveness of more than one dose of ORBACTIV during a single course of therapy have not been established [See Dosage and Administration (2.1)].

5.4 Clostridium difficile-associated Diarrhea

Clostridium difficile-associated diarrhea (CDAD) has been reported for nearly all systemic antibacterial drugs, including ORBACTIV, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin-producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antibacterial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibacterial use. Careful medical history is necessary because CDAD has been reported to occur more than 2 months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, antibacterial use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

5.5 Potential Risk of Bleeding with Concomitant Use of Warfarin

ORBACTIV has been shown to artificially prolong prothrombin time (PT) and international normalized ratio (INR) for up to 12 hours, making the monitoring of the anticoagulation effect of warfarin unreliable up to 12 hours after an ORBACTIV dose [see Warnings and Precautions (5.1)].

Patients should be monitored for bleeding if concomitantly receiving ORBACTIV and warfarin [see Drug Interactions (7.1)].

5.6 Osteomyelitis

In Phase 3 ABSSSI clinical trials, more cases of osteomyelitis were reported in the ORBACTIV treated arm than in the vancomycin-treated arm. Monitor patients for signs and symptoms of osteomyelitis. If osteomyelitis is suspected or diagnosed, institute appropriate alternate antibacterial therapy [see Adverse Reactions (6.1)].

5.7 Development of Drug Resistant Bacteria

Prescribing ORBACTIV in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria [see Patient Counseling Information (17)].

The following adverse reactions are also discussed in the Warnings and Precautions section of labeling:

• Hypersensitivity Reactions [see Warnings and Precautions (5.2)]
• Infusion Related Reactions [see Warnings and Precautions (5.3)]
• Clostridium difficile-associated Diarrhea [see Warnings and Precautions (5.4)]
• Osteomyelitis [see Warnings and Precautions (5.6)]

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of ORBACTIV cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

ORBACTIV has been evaluated in two, double-blind, controlled ABSSSI clinical trials, which included 976 adult patients treated with a single 1200 mg intravenous dose of ORBACTIV and 983 patients treated with intravenous vancomycin for 7 to 10 days. The median age of patients treated with ORBACTIV was 45.6 years, ranging between 18 and 89 years of age with 8.8% ≥65 years of age. Patients treated with ORBACTIV were predominantly male (65.4%), 64.4% were Caucasian, 5.8% were African American, and 28.1% were Asian. Safety was evaluated for up to 60 days after dosing.

In the pooled ABSSSI clinical trials, serious adverse reactions were reported in 57/976 (5.8%) patients treated with ORBACTIV and 58/983 (5.9%) treated with vancomycin. The most commonly reported serious adverse reaction was cellulitis in both treatment groups: 11/976 (1.1%) in ORBACTIV and 12/983 (1.2%) in the vancomycin arms, respectively.

The most commonly reported adverse reactions (≥3%) in patients receiving a single 1200 mg dose of ORBACTIV in the pooled ABSSSI clinical trials were: headache, nausea, vomiting, limb and subcutaneous abscesses, and diarrhea.

In the pooled ABSSSI clinical trials, ORBACTIV was discontinued due to adverse reactions in 36/976 (3.7%) of patients; the most common reported reactions leading to discontinuation were cellulitis (4/976, 0.4%) and osteomyelitis (3/976, 0.3%).

Table 1 provides selected adverse reactions occurring in ≥1.5% of patients receiving ORBACTIV in the pooled ABSSSI clinical trials. There were 540 (55.3%) patients in the ORBACTIV arm and 559 (56.9%) patients in the vancomycin arm, who reported ≥1 adverse reaction.

Table 1. Incidence of Selected Adverse Reactions Occurring in ≥1.5% of Patients Receiving ORBACTIV in the Pooled ABSSSI Clinical Trials:

The following selected adverse reactions were reported in ORBACTIV-treated patients at a rate of less than 1.5%:

Blood and lymphatic system disorders: anemia, eosinophilia

General disorders and administration site conditions: infusion site erythema, extravasation, induration, pruritis, rash, edema peripheral

Immune system disorders: hypersensitivity

Infections and infestations: osteomyelitis

Investigations: total bilirubin increased, hyperuricemia

Metabolism and nutrition disorders: hypoglycemia

Musculoskeletal and connective tissue disorders: tenosynovitis, myalgia

Respiratory, thoracic and mediastinal disorders: bronchospasm, wheezing

Skin and subcutaneous tissue disorders: urticaria, angioedema, erythema multiforme, pruritis, leucocytoclastic vasculitis, rash.

7.1 Effect of ORBACTIV on CYP Substrates

A screening drug-drug interaction study indicated that ORBACTIV is a nonspecific, weak inhibitor (CYP2C9 and CYP2C19) or inducer (CYP3A4 and CYP2D6) of several CYP isoforms [see Clinical Pharmacology (12.3)]. A drug-drug interaction study that assessed the interaction potential of a single 1200 mg dose of ORBACTIV on the pharmacokinetics of S-warfarin (CYP2C9 probe substrate) showed no effect of ORBACTIV on S-warfarin C_max or AUC.

Avoid administering ORBACTIV concomitantly with drugs that are predominantly metabolized by one of the affected CYP450 enzymes, as co-administration may increase or decrease concentrations of those drugs. Patients should be closely monitored for signs of toxicity or lack of efficacy if they have been given ORBACTIV while on a potentially affected compound (e.g. patients should be monitored for bleeding if concomitantly receiving ORBACTIV and warfarin).

7.2 Drug-Laboratory Test Interactions

ORBACTIV may artificially prolong certain laboratory coagulation tests (see Table 2) by binding to and preventing the action of the phospholipid reagents which activate coagulation in commonly used laboratory coagulation tests [see Contraindications (4.1) and Warnings and Precautions (5.1, 5.5)]. For patients who require monitoring of anticoagulation effect within the indicated time after ORBACTIV dosing, a non-phospholipid dependent coagulation test such as a Factor Xa (chromogenic) assay or an alternative anticoagulant not requiring aPTT monitoring may be considered.

ORBACTIV does not interfere with coagulation in vivo. In addition, ORBACTIV does not affect tests that are used for diagnosis of Heparin Induced Thrombocytopenia (HIT).

Table 2. Coagulation Tests Affected and Unaffected by ORBACTIV:

Risk Summary

There are no available data on ORBACTIV use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In animal reproduction studies, no effects on embryo-fetal development or survival were observed in pregnant rats or rabbits treated at the highest doses throughout organogenesis with intravenous oritavancin, at doses equivalent to 25% of the single clinical dose of 1200 mg (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% to 4% and 15% to 20%, respectively.

Data

Animal Data

Reproduction studies performed in rats and rabbits have revealed no evidence of harm to the fetus due to oritavancin at the highest doses administered throughout organogenesis, 30 mg/kg/day (gestation days 6-17) and 15 mg/kg/day (gestation days 7-19), respectively. Those doses would be equivalent to a human dose of 300 mg, or 25% of the single clinical dose of 1200 mg. Higher doses were not evaluated in nonclinical developmental and reproductive toxicology studies.

Risk Summary

There are no data on the presence of oritavancin in human milk, the effects on the breastfed-child, or the effects on milk production. ORBACTIV is present in the breast milk of rats (see Data). When a drug is present in animal milk, it is likely that the drug will be present in human milk.

The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for ORBACTIV and any potential adverse effects on the breast-fed child from ORBACTIV or from the underlying maternal condition.

Data

Following a single intravenous infusion in lactating rats, radio-labeled [¹⁴C]-oritavancin was excreted in milk and absorbed by nursing pups.

Safety and effectiveness of ORBACTIV in pediatric patients (younger than 18 years of age) has not been studied.

The pooled Phase 3 ABSSSI clinical trials of ORBACTIV did not include sufficient numbers of subjects aged 65 and older to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

No dosage adjustment of ORBACTIV is needed in patients with mild or moderate renal impairment [see Dosage and Administration (2.1), Clinical Pharmacology (12.3)]. The pharmacokinetics of ORBACTIV in severe renal impairment have not been evaluated. ORBACTIV is not removed from blood by hemodialysis.

No dosage adjustment of ORBACTIV is needed in patients with mild or moderate hepatic impairment. The pharmacokinetics of ORBACTIV in patients with severe hepatic insufficiency has not been studied [see Dosage and Administration (2.1), Clinical Pharmacology (12.3)].