PEGVISOMANT Drug Interactions: What You Need to Know

INTERACTIONS

• Insulin and/or Oral hypoglycemic Agents: Patients with acromegaly and with diabetes mellitus may require careful monitoring and dose reductions of insulin and/or oral hypoglycemic agents. ( 5.2 , 7.1 )
• Opioids: Patients on opioids may need higher SOMAVERT doses to achieve appropriate IGF-1 suppression. ( 7.2 )

7.1 Insulin and/or Oral Hypoglycemic Agents After initiation of SOMAVERT, patients with acromegaly and diabetes mellitus treated with insulin and/or oral hypoglycemic agents may require dose reductions of insulin and/or oral hypoglycemic agents <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1) ]</span> .

7.2 Opioids In clinical studies, patients taking opioids often needed higher SOMAVERT doses to normalize IGF-1 concentrations compared with patients not receiving opioids. The mechanism of this interaction is not known.

None. None. ( 4 )

AND PRECAUTIONS

• Hypoglycemia : Monitor blood glucose in patients with diabetes mellitus and reduce anti-diabetic drug therapy as necessary. ( 5.1 )
• Liver Toxicity: Should have more frequent liver tests and/or discontinue SOMAVERT. ( 5.2 )
• Systemic Hypersensitivity : Monitor closely when re-initiating SOMAVERT in patients with systemic hypersensitivity. ( 5.5 )

5.1 Hypoglycemia Associated With GH Lowering in Patients With Diabetes Mellitus GH opposes the effects of insulin on carbohydrate metabolism by decreasing insulin sensitivity; thus, glucose tolerance may improve in some patients treated with SOMAVERT. Patients should be carefully monitored and doses of anti-diabetic drugs reduced as necessary to avoid hypoglycemia in patients with diabetes mellitus.

5.2 Liver Toxicity Baseline serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum total bilirubin (TBIL), and alkaline phosphatase (ALP) levels should be obtained prior to initiating therapy with SOMAVERT.

Table

1 lists recommendations regarding initiation of treatment with SOMAVERT, based on the results of these liver tests (LTs). Asymptomatic, transient elevations in transaminases up to 15 times ULN have been observed in <2% of subjects among two open-label trials (with a total of 147 patients). These reports were not associated with an increase in bilirubin. Transaminase elevations normalized with time, most often after suspending treatment. Postmarketing reports have identified elevations in serum hepatic transaminases up to greater than 20 times ULN associated with elevation in total bilirubin greater than 2 times ULN. In many of these cases, discontinuation of SOMAVERT therapy resulted in improvement or resolution of hepatic laboratory abnormalities. SOMAVERT should be used in accordance with the information presented in Table 2 with respect to liver test abnormalities while on SOMAVERT treatment.

Table

1. Recommendations of Initiating SOMAVERT Based on Baseline LTs and Periodic Monitoring of LTs During SOMAVERT Treatment Baseline LT Levels Recommendations Normal

• May treat with SOMAVERT.
• Monitor LTs at monthly intervals during the first 6 months of treatment, quarterly for the next 6 months and then bi-annually for the next year. Elevated, but less than or equal to 3 times ULN May treat with SOMAVERT; however, monitor LTs monthly for at least one year after initiation of therapy and then bi-annually for the next year. Greater than 3 times ULN
• Do not treat with SOMAVERT until a comprehensive workup establishes the cause of the patient's liver dysfunction.
• Determine if cholelithiasis or choledocholithiasis is present, particularly in patients with a history of prior therapy with somatostatin analogs.
• Based on the workup, consider initiation of therapy with SOMAVERT.
• If the decision is to treat, LTs and clinical symptoms should be monitored very closely. If a patient develops LT elevations, or any other signs or symptoms of liver dysfunction while receiving SOMAVERT, the following patient management is recommended (Table 2).

Table

2.

Clinical Recommendations

Based on Liver Test Results While on SOMAVERT LT Levels and Clinical Signs/Symptoms Recommendations Greater than or equal to 3 but less than 5 times ULN (without signs/symptoms of hepatitis or other liver injury, or increase in serum TBIL)

• May continue therapy with SOMAVERT. However, monitor LTs weekly to determine if further increases occur (see below).
• Perform a comprehensive hepatic workup to discern if an alternative cause of liver dysfunction is present. At least 5 times ULN, or transaminase elevations at least 3 times ULN associated with any increase in serum TBIL (with or without signs/symptoms of hepatitis or other liver injury)
• Discontinue SOMAVERT immediately.
• Perform a comprehensive hepatic workup, including serial LTs, to determine if and when serum levels return to normal.
• If LTs normalize (regardless of whether an alternative cause of the liver dysfunction is discovered), consider cautious re-initiation of therapy with SOMAVERT, with frequent LT monitoring. Signs or symptoms suggestive of hepatitis or other liver injury (e.g., jaundice, bilirubinuria, fatigue, nausea, vomiting, right upper quadrant pain, ascites, unexplained edema, easy bruisability)
• Immediately perform a comprehensive hepatic workup.
• If liver injury is confirmed, SOMAVERT should be discontinued.

5.3 Cross-Reactivity With GH Assays SOMAVERT has significant structural similarity to growth hormone (GH) which causes it to cross-react in commercially available GH assays. Since serum concentrations of therapeutically effective doses of SOMAVERT are generally 100 to 1000 times higher than the actual serum GH concentrations seen in patients with acromegaly, measurements of serum GH concentrations will appear falsely elevated.

5.4 Lipohypertrophy There have been cases of lipohypertrophy in patients treated with SOMAVERT. In a double-blind, 12-week, placebo-controlled study, there was one case (1.3%) of injection site lipohypertrophy reported in a subject receiving 10 mg/day. The subject recovered while on treatment. Among two open-label trials (with a total of 147 patients), there were two subjects, both receiving 10 mg/day, who developed lipohypertrophy. One case recovered while on treatment, and one case resulted in a discontinuation of treatment. Injection sites should be rotated daily to help prevent lipohypertrophy (different area than the last injection).

5.5 Systemic Hypersensitivity In patients with systemic hypersensitivity reactions, caution and close monitoring should be exercised when re-initiating SOMAVERT therapy <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> .