Byetta Drug Information

• BYETTA is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Limitations of Use
• BYETTA contains exenatide. Coadministration with other exenatide-containing products is not recommended. BYETTA (exenatide) is a glucagon-like peptide-1 (GLP-1) receptor agonist indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Limitations of Use
• Coadministration with other exenatide-containing products is not recommended.

Recommended Dosing • Initiate BYETTA at 5 mcg administered subcutaneously twice daily at any time within the 60-minute period before the morning and evening meals (or before the two main meals of the day, approximately 6 hours or more apart). Do not administer after a meal. • Based on clinical response, the dose of BYETTA can be increased to 10 mcg twice daily which is recommended after 1 month of therapy, in order to reduce the risk of gastrointestinal adverse reactions. • Administer as a subcutaneous injection in the thigh, abdomen, or upper arm. • Rotate injections sites with each dose. Do not use the same site for each injection. • Inspect visually for particulate matter and discoloration.

Only use BYETTA if the solution appears clear, colorless, and contains no particles. • When using BYETTA with insulin, administer as separate injections and never mix. It is acceptable to inject BYETTA and insulin in the same body region, but the injections should not be adjacent to each other. • If a dose is missed, resume the treatment regimen as prescribed with the next scheduled dose.

Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Hypoglycemia Table 1 summarizes the incidence and rate of hypoglycemia with BYETTA in six placebo-controlled clinical trials. Table 1: Incidence (%) and Rate of Hypoglycemia when BYETTA was used as Monotherapy or with Concomitant Antidiabetic Therapy in Six Placebo-Controlled Clinical Trials A hypoglycemic episode was recorded if a patient reported symptoms of hypoglycemia with or without a blood glucose value consistent with hypoglycemia.

Severe hypoglycemia was defined as an event with symptoms consistent with hypoglycemia requiring the assistance of another person and associated with either a documented blood glucose value <54 mg/dL or prompt recovery after treatment for hypoglycemia. Immunogenicity Antibodies were assessed in 90% of subjects in the 30-week, 24-week, and 16-week studies of BYETTA. In the 30-week controlled trials of BYETTA add-on to metformin and/or sulfonylurea, antibodies were assessed at 2- to 6-week intervals.

The mean antibody titer peaked at Week 6 and was reduced by 55% by Week 30. Three hundred and sixty patients (38%) had low titer antibodies (<625) to exenatide at 30 weeks. The level of glycemic control (HbA 1c ) in these patients was generally comparable to that observed in the 534 patients (56%) without antibody titers.

In the 16-week trial of BYETTA add-on to thiazolidinediones, with or without metformin, 36 patients (31%) had low titer antibodies to exenatide at 16 weeks. The level of glycemic control in these patients was generally comparable to that observed in the 69 patients (60%) without antibody titer. An additional 10 patients (9%) had higher titer antibodies at 16 weeks.

In the 24-week trial of BYETTA used as monotherapy, 40 patients (28%) had low titer antibodies to exenatide at 24 weeks. The level of glycemic control in these patients was generally comparable to that observed in the 101 patients (70%) without antibody titers. An additional 3 patients (2%) had higher titer antibodies at 24 weeks.

Antibodies to exenatide were not assessed in the 30-week placebo-controlled trial of BYETTA used in combination with insulin glargine. In the 30-week comparator-controlled trial of BYETTA used in combination with insulin glargine and metformin, 60 patients (20%) had low titer antibodies to exenatide at 30 weeks. An additional 10 patients (3%) had higher titer antibodies at 30 weeks.

Two hundred and ten patients with antibodies to exenatide in the BYETTA clinical trials were tested for the presence of cross-reactive antibodies to GLP-1 and/or glucagon. No treatment-emergent cross-reactive antibodies were observed across the range of titers. Other Adverse Reactions Monotherapy For the 24-week placebo-controlled study of BYETTA used as a monotherapy, Table 2 summarizes adverse reactions (excluding hypoglycemia) occurring with an incidence ≥2% and occurring more frequently in BYETTA-treated patients compared with placebo-treated patients.

Table 2: Treatment-Emergent Adverse Reactions ≥2% Incidence with BYETTA used as Monotherapy (excluding Hypoglycemia) In a 24-week placebo-controlled trial. Adverse reactions reported in ≥1.0% to <2.0% of patients receiving BYETTA and reported more frequently than with placebo included decreased appetite, diarrhea, and dizziness. The most frequently reported adverse reaction associated with BYETTA, nausea, occurred in a dose-dependent fashion.

Two of the 155 patients treated with BYETTA withdrew due to adverse reactions of headache and nausea. No placebo-treated patients withdrew due to adverse reactions. Cholelithiasis and cholecystitis In a clinical study with exenatide, 1.9% of exenatide-treated patients and 1.4% of placebo-treated patients reported an acute event of gallbladder disease, such as cholelithiasis or cholecystitis.

Combination Therapy Add-On to Metformin and/or Sulfonylurea In the three 30-week controlled trials of BYETTA add-on to metformin and/or sulfonylurea, adverse reactions (excluding hypoglycemia) with an incidence ≥2% and occurring more frequently in BYETTA-treated patients compared with placebo-treated patients are summarized in Table 3. Table 3: Treatment-Emergent Adverse Reactions ≥2% Incidence and Greater Incidence with BYETTA Treatment used with Metformin and/or a Sulfonylurea (excluding Hypoglycemia) In three 30-week placebo-controlled clinical trials. Nausea was the most frequently reported adverse reaction and occurred in a dose-dependent fashion.

With continued therapy, the frequency and severity decreased over time in most of the patients who initially experienced nausea. Patients in the long-term uncontrolled open-label extension studies at 52 weeks reported no new types of adverse reactions than those observed in the 30-week controlled trials. The most common adverse reactions leading to withdrawal for BYETTA-treated patients were nausea (3% of patients) and vomiting (1%).

For placebo-treated patients, <1% withdrew due to nausea and none due to vomiting. Add-On to Thiazolidinedione with or without Metformin For the 16-week placebo-controlled study of BYETTA add-on to a thiazolidinedione, with or without metformin, Table 4 summarizes the adverse reactions (excluding hypoglycemia) with an incidence of ≥2% and occurring more frequently in BYETTA-treated patients compared with placebo-treated patients. Table 4: Treatment-Emergent Adverse Reactions ≥2% Incidence with BYETTA used with a Thiazolidinedione (TZD), with or without Metformin (MET) (excluding Hypoglycemia) In a 16-week placebo-controlled clinical trial.

Chills (n=4) and injection-site reactions (n=2) occurred only in BYETTA-treated patients. The two patients who reported an injection-site reaction had high titers of antibodies to exenatide. Two serious adverse events (chest pain and chronic hypersensitivity pneumonitis) were reported in the BYETTA arm.

No serious adverse events were reported in the placebo arm. The most common adverse reactions leading to withdrawal for BYETTA-treated patients were nausea (9%) and vomiting (5%). Table 5: Treatment-Emergent Adverse Reactions ≥2% Incidence with BYETTA used with Insulin Glargine with or without Oral Antihyperglycemic Medications (excluding Hypoglycemia) In a 30-week placebo-controlled clinical trial.

No placebo-treated patients withdrew due to nausea or vomiting.

Postmarketing Experience

The following additional adverse reactions have been reported during post approval use of BYETTA or other formulations of exenatide. Because these events are reported voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood: Drug induced thrombocytopenia.

Drug Interactions: International normalized ratio (INR) increased with concomitant warfarin use sometimes associated with bleeding. Gastrointestinal: Nausea, vomiting, and/or diarrhea resulting in dehydration; abdominal distension, abdominal pain, eructation, constipation, flatulence, ileus, acute pancreatitis, hemorrhagic and necrotizing pancreatitis sometimes resulting in death Hepatobiliary: Cholecystitis, cholelithiasis requiring cholecystectomy. Hypersensitivity: Injection-site reactions, generalized pruritus and/or urticaria, macular or papular rash, angioedema, anaphylactic reaction.

Neurologic: Dysgeusia, somnolence, dysesthesia. Pulmonary: Pulmonary aspiration has occurred in patients receiving GLP-1 receptor agonists undergoing elective surgeries or procedures requiring general anesthesia or deep sedation. Renal: Altered renal function, including increased serum creatinine, renal impairment, worsened chronic renal failure or acute renal failure (sometimes requiring hemodialysis), kidney transplant, and kidney transplant dysfunction.

Skin and Subcutaneous Tissue: Alopecia.

• May impact absorption of orally administered medications.
• Warfarin: Postmarketing reports of increased INR sometimes associated with bleeding. Monitor INR frequently until stable upon initiation or alteration of BYETTA therapy. Generic Section Table 6: Clinically Relevant Interactions with BYETTA Concomitant Use of Insulin Secretagogues or Insulin Clinical Impact Exenatide promotes insulin release from pancreatic beta-cells in the presence of elevated glucose concentrations. The risk of hypoglycemia is increased when exenatide is used in combination with insulin secretagogues (e.g., sulfonylureas) or insulin. Intervention When initiating BYETTA, consider reducing the dose of concomitantly administered insulin secretagogue or insulin to reduce the risk of hypoglycemia. Warfarin Clinical Impact In a drug interaction study, BYETTA did not have a significant effect on INR. There have been postmarketing reports for BYETTA of increased INR with concomitant use of warfarin, sometimes associated with bleeding. Intervention In patients taking warfarin, the prothrombin time should be monitored more frequently after initiation or alteration of BYETTA therapy. Orally Administered Drugs (e.g., acetaminophen) Clinical Impact Exenatide slows gastric emptying. Therefore, BYETTA has the potential to reduce the rate of absorption of orally administered drugs. Intervention Use caution when administering oral medications with BYETTA where a slower rate of oral absorption may be clinically meaningful. If such drugs are to be administered with food, patients should be advised to take them with a meal or snack when BYETTA is not administered.

Pregnancy Risk Summary Limited data with BYETTA in pregnant women are not sufficient to determine a drug-associated risk for major birth defects or miscarriage. There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy (see Clinical Considerations ). Based on animal reproduction studies, there may be risks to the fetus from exposure to BYETTA during pregnancy.

BYETTA should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal reproduction studies identified increased adverse fetal and neonatal outcomes from exposure to exenatide during pregnancy and lactation in association with maternal effects. In mice, exenatide administered during gestation and lactation caused increased neonatal deaths at systemic exposure 3-times the human exposure resulting from the maximum recommended human dose (MRHD) of 20 mcg/day for BYETTA (see Data ).

The estimated background risk of major birth defects is 6-10% in women with pre-gestational diabetes with an HbA1c >7 and has been reported to be as high as 20-25% in women with HbA1c >10. The estimated background risk of miscarriage for the indicated population is unknown. 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 embryofetal risk Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, preeclampsia, spontaneous abortions, preterm delivery, and delivery complications. Poorly controlled diabetes increases the fetal risk for major birth defects, stillbirth, and macrosomia related morbidity. Data Animal Data In studies evaluating reproduction and development in pregnant mice and rabbits, maternal animals were administered exenatide, the active ingredient in BYETTA, by subcutaneous injection twice a day.

In pregnant mice given mcg/kg/day exenatide during fetal organogenesis, skeletal variations associated with slowed fetal growth, including changes in number of rib pairs or vertebral ossifications sites, and wavy ribs were observed at 760 mcg/kg/day, a dose that produced maternal toxicity and yielded systemic exposure 390-times the human exposure resulting from the MRHD of BYETTA based on AUC comparison. In pregnant rabbits given mcg/kg/day exenatide during fetal organogenesis, irregular fetal skeletal ossifications were observed at 2 mcg/kg/day, a dose yielding systemic exposure up to 12-times the human exposure from the MRHD of BYETTA based on AUC comparison.

Pediatric Use The safety and effectiveness of BYETTA have not been established in pediatric patients.

• BYETTA is contraindicated in patients with:
• A prior severe hypersensitivity reaction to exenatide or to any of the excipients in BYETTA. Serious hypersensitivity reactions including anaphylaxis and angioedema have been reported with BYETTA.
• A history of drug-induced immune-mediated thrombocytopenia from exenatide products. Serious bleeding, which may be fatal, from drug-induced immune-mediated thrombocytopenia has been reported with exenatide use.
• History of severe hypersensitivity to exenatide or any of the excipients in BYETTA.
• History of drug-induced immune-mediated thrombocytopenia from exenatide products.

In a clinical study of BYETTA, three patients with type 2 diabetes each experienced a single overdose of 100 mcg SC (10 times the maximum recommended dose). Effects of the overdoses included severe nausea, severe vomiting, and rapidly declining blood glucose concentrations. One of the three patients experienced severe hypoglycemia requiring parenteral glucose administration.

The three patients recovered without complication. In the event of overdose, consider contacting the Poison Help line (1-800-222-1222) or a medical toxicologist for additional overdosage management recommendations. Initiate appropriate supportive treatment according to the patient's clinical signs and symptoms.