Neumega (oprelvekin) a nonglycosylated IL-11 isproduced in E. coli by recombinant DNA technology and has 177 amino acids in length and a molecular mass of approximately 19 kDa. It differs from the 178 amino acid length of native IL-11 in lacking the amino-terminal proline residue. It is used as a thrombopoietic GF that directly stimulates the pro-liferation of hematopoietic stem cells and megakar-yocyte progenitor cells and induces megakaryocyte maturation resulting in increased platelet production. Pharmacokinetics shows a rapid clearance from the serum and distribution to highly perfused organs. The kidneys are the primary route of elimination and little intact product can be found in the urine. After injection the Cmax of 17.4 (+–) 5.4 ng/mL is reached after 3.2 (+–) 2.4 hr (Tmax) with a half-life of 6.9 (+–) 1.7 hr. The absolute bioavailability is > 80%. There is no accumulation after multiple doses. Patients with severely impaired renal function show a marked decrease in clearance to 40% of that seen in subjects with normal renal function.
Neumega is supplied as single-use vials contain-ing 5 mg of oprelvekin (specific activity approximately 8 106 U/mg) as a sterile lyophilized powder with 23 mg of glycine, 1.6 mg of dibasic sodium phosphate heptahydrate, and 0.55 mg monobasic sodium phos-phate monohydrate. When reconstituted with 1 mL of sterile water for injection, the solution has a pH of 7.0. It is indicated for the prevention of severe thrombocyto-penia following myelosuppressive chemotherapy. The recommended dose is 50 μg/kg given once daily by SC injection after a chemotherapy cycle in courses of 10 to 21 days. Platelet counts should be monitored to assess the optimal course of therapy. Treatment beyond 21 days is not recommended. Oprelvekin is generally well tolerated. Reported adverse events, mainly as a consequence of fluid retention, include edema, tachy-cardia/palpitations, dyspnea, and oral moniliasis. For a detailed reporting of all adverse events, rarely severe, the reader is referred to the product information for Neumega.