Procrit Clinical Pharmacology

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Procrit - Clinical Pharmacology [Epoetin alfa]

The rate of hematocrit increase varies between patients and is dependent upon the dose of PROCRIT, within a therapeutic range of approximately 50-300 Units/ kg (T. I. W.). 4 A greater biologic response is not observed at doses exceeding 300 Units/ kg (T. I. W.). 6 Other factors affecting the rate and extent of response include availability of iron stores, the baseline hematocrit, and the presence of concurrent medical problems.

Zidovudine-Treated HIV-Infected Patients

Responsiveness to PROCRIT in HIV-infected patients is dependent upon the endogenous serum erythropoietin level prior to treatment. Patients with endogenous serum erythropoietin levels 500 mUnits/ mL, and who are receiving a dose of zidovudine 4,200 mg/ week, may respond to PROCRIT therapy. Patients with endogenous serum erythropoietin levels > 500 mUnits/ mL do not appear to respond to PROCRIT therapy. In a series of four clinical trials involving 255 patients, 60% to 80% of HIV-infected patients treated with zidovudine had endogenous serum erythropoietin levels 500 mUnits/ mL. Response to PROCRIT in zidovudine-treated, HIV-infected patients is manifested by reduced transfusion requirements and increased hematocrit.

Cancer Patients on Chemotherapy

Anemia in cancer patients may be related to the disease itself or the effect of concomitantly administered chemotherapeutic agents. PROCRIT has been shown to increase hematocrit and decrease transfusion requirements after the first month of therapy (months 2 and 3), in anemic cancer patients undergoing chemotherapy. A series of clinical trials enrolled 131 anemic cancer patients who were receiving cyclic cisplatin-or non-cisplatin-containing chemotherapy.

Endogenous baseline serum erythropoietin levels varied among patients in these trials with approximately 75% (N= 83/ 110) having endogenous serum erythropoietin levels 132 mUnits/ mL, and approximately 4% (N= 4/ 110) of patients having endogenous serum erythropoietin levels > 500 mUnits/ mL. In general, patients with lower baseline serum erythropoietin levels responded more vigorously to PROCRIT than patients with higher baseline erythropoietin levels. Although no specific serum erythropoietin level can be stipulated above which patients would be unlikely to respond to PROCRIT therapy, treatment of patients with grossly elevated serum erythropoietin levels (e. g., > 200 mUnits/ mL) is not recommended.