Drug Detail:Pegvisomant (Pegvisomant [ peg-vih-so-mant ])
Drug Class: Growth hormone receptor blockers
Usual Adult Dose for Acromegaly
Loading dose: 40 mg subcutaneously once under medical supervision
Initial dose: 10 mg subcutaneously once a day
Maintenance dose: 10 to 30 mg subcutaneously once a day
Maximum dose: 30 mg per day
Comments:
- Assess baseline liver tests of alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum total bilirubin (TBIL), and alkaline phosphatase (ALP) prior to therapy initiation.
Renal Dose Adjustments
Data not available
Liver Dose Adjustments
Dosing based on baseline liver tests (LTs) of alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum total bilirubin (TBIL), and alkaline phosphatase (ALP).
Normal LT:
- May treat with this drug.
- Monitor LTs monthly for 6 months, quarterly for 6 months, then bi-annually the next year
Elevated LT, but under 3 times (X) the upper limit of normal (ULN):
- May treat with this drug.
- Monitor LTs monthly for at least 1 year, then biannually the next year
LT over 3 X ULN:
- Do not administer until a comprehensive workup establishes the cause of liver dysfunction.
- Determine if cholelithiasis or choledocholithiasis are present, especially in patients previously treated with somatostatin analogs.
- Consider treatment based on workup.
- Monitor LTs and clinical symptoms closely if treatment is commenced.
Patients who develop LT elevations or other signs of liver dysfunction on treatment:
LT over 3 but less than 5 X ULN (no hepatitis/liver injury symptoms, no increase in TBIL):
- May continue treatment
- Monitor LTs weekly
- Perform comprehensive hepatic workup for alternative causes of liver dysfunction.
LT at least 5 X ULN, or transaminase elevations at least 3 X ULN with any TBIL increase (with/without hepatitis/liver injury symptoms):
- Discontinue therapy immediately
- Perform comprehensive hepatic workup including serial LTs to determine if/when levels return to normal.
- If LTs normalize (regardless of finding other liver dysfunction causes), may cautiously restart treatment, with frequent LT monitoring.
Signs or symptoms suggesting hepatitis or other liver injury (e.g. jaundice, bilirubinemia, fatigue, nausea, vomiting, right upper quadrant pain, ascites, unexplained edema, easy bruising):
- Immediately perform comprehensive hepatic workup.
- Discontinue therapy if liver injury is confirmed.
Dose Adjustments
Titrate dose to normalize serum IGF-I.
- Increase dose by 5 mg increments every 4 to 6 weeks if IGF-I is elevated.
- Decrease dose by 5 mg increments every 4 to 6 weeks if IGF-I is below normal.
- Monitor IGF-I levels if dose is converted from multiple injections into a single daily injection.
- Do not base dose on growth hormone (GH) concentrations or symptoms of acromegaly.
- It is unknown if patients with normal IGF-I who continue to be symptomatic would benefit from higher doses.
Precautions
CONTRAINDICATIONS: None
Safety and efficacy have not been established in patients younger than 18 years.
Consult WARNINGS section for additional precautions.
Dialysis
Data not available
Other Comments
Administration advice:
- Rotate injection site daily to avoid lipodystrophy.
Storage requirements:
- Refrigerate; do not freeze
