Blinded, randomized, multicenter study to evaluate single administration pegfilgrastim once per cycle versus daily filgrastim as an adjunct to chemotherapy in patients with high-risk stage II or stage III/IV breast cancer

Chemotherapy-induced neutropenia

Cytotoxic chemotherapy suppresses the hematopoietic system, impairing host protective mechanisms and limiting the doses of chemotherapy that can be tolerated. Neutropenia, the most serious hematologic toxicity, is associated with the risk of life-threatening infections as well as chemotherapy dose reductions and delays that may compromise treatment outcomes. The authors reviewed the recent literature to provide an update on research in chemotherapy-induced neutropenia and its complications and impact, and they discuss the implications of this work for improving the management of patients with cancer who are treated with myelosuppressive chemotherapy. Despite its importance as the primary dose-limiting toxicity of chemotherapy, much concerning neutropenia and its consequences and impact remains unknown. Recent surveys indicate that neutropenia remains a prevalent problem associated with substantial morbidity, mortality, and costs. Much research has sought to identify risk factors that may predispose patients to neutropenic complications, including febrile neutropenia, in an effort to predict better which patients are at risk and to use preventive strategies, such as prophylactic colony-stimulating factors, more cost-effectively. Neutropenic complications associated with myelosuppressive chemotherapy are a significant cause of morbidity and mortality, possibly compromised treatment outcomes, and excess healthcare costs. Research in quantifying the risk of neutropenic complications may make it possible in the near future to target patients at greater risk with appropriate preventive strategies, thereby maximizing the benefits and minimizing the costs.

The impact of frequent injections for hematopoietic growth factor support on patients receiving chemotherapy: an observational study

BACKGROUND: Quality of life may be affected by daily injections of supportive hematopoietic growth factor medication, which is frequently required by patients with cancer undergoing chemotherapy. The objective of the study was to identify areas where long-acting derivatives of current proteins, which require less frequent administration, may provide advantages over existing therapies that require more frequent administration. METHODS: An observational study was conducted to assess the impact of daily injections of Filgrastim (NeupogencircledR;; Amgen Inc.) on patients' quality of life. A Subject Outcome Questionnaire was administered to patients after chemotherapy on 2 consecutive cycles. Time spent for treatment and patient attitude towards injection frequency were measured. The effect on patients' daily activities, including their ability to work, was analyzed. RESULTS: Thirty patients completed the first, and 24 the second, administration of the Questionnaire across 3 participating sites in the United States. The average patient time commitment for each daily injection was 78 minutes. Forty-five percent of patients were moderately to extremely bothered by travel during the first chemotherapy cycle, which increased to 59% during the second cycle. Forty-four percent and 18% of patients reported having to rearrange their daily schedules and take time off from work to accommodate each injection at least some of the time, respectively. Eighty-nine percent of the patients reported a preference for a longer-acting drug that required fewer injections. CONCLUSION: Results indicate that frequent injections represent a significant burden on patients' lives and that the majority would prefer longer-acting medications that require less frequent administration and potentially fewer clinic visits.

Pegfilgrastim, a sustained-duration form of filgrastim, significantly improves neutrophil recovery after autologous marrow transplantation in rhesus macaques

Daily administration of filgrastim decreases the duration of severe neutropenia in the clinical setting. A sustained-duration form of filgrastim, pegfilgrastim, significantly reduces scheduling protocols to a single injection per chemotherapy cycle while maintaining therapeutic efficiency. We examined the ability of a single injection of pegfilgrastim to significantly improve neutrophil recovery following autologous bone marrow transplantation (AuBMT) in rhesus macaques. On day 1, postmyeloablation (920 cGy x-irradiation) and AuBMT, animals received either 0.1% autologous serum for 18 consecutive days (n=13), or single doses of pegfilgrastim via the subcutaneous (s.c.) or intravenous (i.v.) route (300 or 100 micro g/kg), or a single dose of filgrastim at 300 micro g/kg via the s.c. or i.v. route, or filgrastim at 10 micro g/kg via the s.c. route (n=4) on a daily basis (range=days 12-17). Pharmacokinetic parameters and neutrophil recovery were assessed. A single dose of pegfilgrastim via the i.v. or s.c. route was as effective as daily filgrastim administration, resulting in significant improvement of neutrophil recovery after myeloablation and ABuMT. Effective pegfilgrastim plasma concentrations were maintained in neutropenic animals until after the onset of hematopoietic recovery. Enhanced pharmacokinetics in AuBMT cohorts are consistent with self-regulating, neutrophil-mediated clearance.

Phase III trial of paclitaxel at two dose levels, the higher dose accompanied by filgrastim at two dose levels in platinum-pretreated epithelial ovarian cancer: an intergroup study

PURPOSE

To determine if increasing the dose of paclitaxel increases the probability of clinical response, progression-free survival, or overall survival in women who have persistent or recurrent ovarian cancer, and whether doubling the dose of prophylactic filgrastim accompanying the higher paclitaxel dose decreases the frequency of neutropenic fever.

PATIENTS AND METHODS

Consenting patients with persistent, recurrent, or progressing ovarian cancer, despite first-line platinum therapy (but no prior taxane), were randomly assigned to paclitaxel 135 mg/m2, 175 mg/m2, or 250 mg/m2 over 24 hours every 3 weeks. Patients receiving paclitaxel 250 mg/m2 were also randomly assigned to 5 or 10 microg/kg of filgrastim per day subcutaneously.

RESULTS

Accession to the paclitaxel 135-mg/m2 arm was closed early. Among the 271 patients on the other regimens with measurable disease, partial and complete response on paclitaxel 250 mg/m2 (36%) was significantly higher than on 175 mg/m2 (27%, P =.027). This difference was more evident among patients who never responded to prior platinum. However, progression-free and overall survival results were similar. The median durations of overall survival were 13.1 and 12.3 months for paclitaxel 175 mg/m2 and 250 mg/m2, respectively. Thrombocytopenia, neuropathy, and myalgia were greater with paclitaxel 250 mg/m2 (P <.05). The incidence of neutropenic fever after the first cycle of paclitaxel 250 mg/m2 was 19% and 18% on the 5-microg/kg and 10-microg/kg filgrastim dose, respectively (22% for paclitaxel 175 mg/m2 without filgrastim).

CONCLUSION

Paclitaxel exhibits a dose effect with regard to response rate, but there is more toxicity and no survival benefit to justify paclitaxel 250 mg/m2 plus filgrastim. Doubling the filgrastim dose from 5 to 10 microg/kg did not reduce the probability of neutropenic fever after high-dose paclitaxel.

Treatment of breast cancer with chemotherapy in combination with filgrastim: approaches to improving therapeutic outcome

Chemotherapy improves disease-free and overall survival in breast cancer, and its benefit is directly related to the percentage of the planned dose that is actually administered. In all current chemotherapeutic regimens, a substantial proportion of patients have reductions and/or delays in dosage due to side effects. In about half such cases, the delays or reductions are related to neutropenia. Overall, approximately 30% of patients have a reduction to less than 85% of the planned dosage. Women aged > or = 50 years are more likely to experience a reduction or delay in dose. Dose-intense regimens (excluding myeloablative high-dose chemotherapy) which increase the dose of chemotherapy or reduce the interval between cycles, or both, are a promising approach now under investigation. The human granulocyte colony-stimulating factor filgrastim reduces the incidence of neutropenia and facilitates adherence to full dose intensity in both standard and dose-intensified regimens. A model based on the first-cycle absolute neutrophil count nadir has been developed and validated to determine which patients should receive filgrastim. A cost benefit associated with the use of filgrastim in patients with breast cancer has been realised. This may lead to a re-evaluation of the current treatment guidelines.

Pegfilgrastim administered once per cycle reduces incidence of chemotherapy-induced neutropenia

Neutropenia is a common and potentially dangerous adverse effect of cancer chemotherapy. It also often necessitates a reduction or delay in dose, thus compromising efficacy. The human granulocyte colony-stimulating factor filgrastim has been proven to have a good safety profile and to be effective in accelerating neutrophil recovery and reducing the incidence of infections following myelosuppressive chemotherapy. However, its short serum half-life necessitates daily administration. Pegylated filgrastim (pegfilgrastim) was developed by attaching a polyethylene glycol moiety to the filgrastim protein. Pegfilgrastim binds to the same cell surface receptor on neutrophils and their precursors as filgrastim and stimulates the proliferation and differentiation of neutrophils through the same mechanism. However, because of the pegylation, it is minimally cleared by the kidneys and has a much longer serum half-life. Furthermore, its clearance is neutrophil dependent and thus 'self-regulated'. Pegfilgrastim is administered as a single subcutaneous injection per cycle of chemotherapy. In clinical trials it has been shown to be comparable in efficacy to filgrastim in decreasing the incidence of infection as manifested by febrile neutropenia following chemotherapy. Its safety profile and tolerability are similar to those of filgrastim.

Randomized, multicenter, open-label study of pegfilgrastim compared with daily filgrastim after chemotherapy for lymphoma

PURPOSE

The primary objective was to assess the duration of grade 4 neutropenia (neutrophil count < 0.5 x 10(9)/L) after one cycle of chemotherapy with etoposide, methylprednisolone, cisplatin, and cytarabine in patients randomly assigned to receive one dose of pegfilgrastim or daily filgrastim after chemotherapy. Febrile neutropenia, neutrophil profiles, time to neutrophil recovery, pharmacokinetics, and safety were also assessed.

PATIENTS AND METHODS

An open-label, randomized, phase II study was designed to compare the effects of a single subcutaneous injection of pegfilgrastim (sustained-duration filgrastim) 100 micro g/kg per chemotherapy cycle (n = 33) with daily subcutaneous injections of filgrastim 5 micro g/kg (n = 33) in patients receiving salvage chemotherapy for relapsed or refractory Hodgkin's or non-Hodgkin's lymphoma.

RESULTS

The incidence of grade 4 neutropenia in the pegfilgrastim and filgrastim groups was 69% and 68%, respectively. In addition, the mean duration of grade 4 neutropenia was similar in both groups (2.8 and 2.4 days, respectively). The results for the two groups were also not significantly different for febrile neutropenia, neutrophil profile, time to neutrophil recovery, or toxicity profile. A single subcutaneous injection of pegfilgrastim 100 micro g/kg produced a sustained serum concentration relative to daily subcutaneous injections of filgrastim. Filgrastim-treated patients received a median of 11 injections per cycle.

CONCLUSION

Pegfilgrastim was safe and well tolerated in this patient population. A single injection of pegfilgrastim per chemotherapy cycle provided neutrophil support with safety and efficacy similar to that provided by daily injections of filgrastim. Once-per-cycle administration of pegfilgrastim simplifies the management of neutropenia and may have important clinical benefits for patients and healthcare providers.

Pegfilgrastim

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Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The July 2002 Formulary monograph topics are voriconazole, treprostinil sodium injection, ranolazine, alefacept, and pregabalin. The DUE is on voriconazole.