Peter Bowers

Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

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Publications (12)100.55 Total impact

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    ABSTRACT: Extended-interval dosing of epoetin alfa (EPO) is commonly used to treat anemia in patients with chronic kidney disease (CKD). This study aimed to demonstrate that EPO dosed every 2 weeks (Q2W) and every 4 weeks (Q4W) was noninferior to once-weekly (QW) dosing. 430 anemic subjects with stage 3 to 4 CKD receiving a stable QW dose of EPO were randomized 1:1:2 to QW, Q2W, and Q4W dosing for 36 weeks. Hemoglobin (Hb) was measured weekly, and the dose of EPO was adjusted to maintain an Hb level of 11.0 to 11.9 g/dl. The primary endpoint was change in Hb from baseline to the average of the last 12 weeks of treatment. Both the Q2W and Q4W dosing groups were noninferior to the QW group. The estimated difference of the mean change in Hb between Q2W and QW was -0.03 g/dl; and between Q4W and QW was -0.09 g/dl. From weeks 13 to 37, the mean percentage of weeks per subject with Hb 10.0 to 11.9 g/dl, inclusive, was 81% for QW, 81% for Q2W, and 75% for Q4W. Death occurred, respectively, in 4%, 3%, and 4%; thromboembolic vascular events occurred in 3%, 5%, and 3%; and serious adverse events occurred in 22%, 26%, and 26% of subjects. Q2W and Q4W EPO dosing maintained Hb levels in subjects with stage 3 to 4 CKD. Deaths, thromboembolic vascular events, and serious adverse events were comparable across the dosing groups.
    Clinical Journal of the American Society of Nephrology 02/2010; 5(4):598-606. · 5.07 Impact Factor
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    ABSTRACT: In clinical practice, physicians often use once-weekly (QW) and biweekly (Q2W) dosing of epoetin alfa to treat anemia in patients with chronic kidney disease (CKD). Although the literature supports this practice, previous studies were limited by short treatment duration, lack of randomization, or absence of the approved three times per week (TIW) dosing arm. This randomized trial evaluated extended dosing regimens of epoetin alfa, comparing QW and Q2W to TIW dosing in anemic CKD subjects. The primary objective was to show that treatment with epoetin alfa at QW and Q2W intervals was not inferior to TIW dosing. 375 subjects with stage 3 to 4 CKD were randomized equally to the three groups and treated for 44 wk; to explore the impact of changing from TIW to QW administration on hemoglobin (Hb) control and adverse events, subjects on TIW switched to QW after 22 wk. The Hb was measured weekly, and the dose of epoetin alfa was adjusted to achieve and maintain an Hb level of 11.0 to 11.9 g/dl. Both the QW and Q2W regimens met the primary efficacy endpoint. More subjects in the TIW group than in the QW and Q2W groups exceeded the Hb ceiling. Adverse events were similar across treatment groups and consistent with the morbidities of CKD patients. Administration of epoetin alfa at QW and Q2W intervals are potential alternatives to TIW dosing for the treatment of anemia in stage 3 to 4 CKD subjects.
    Clinical Journal of the American Society of Nephrology 09/2009; 4(11):1731-40. · 5.07 Impact Factor
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    ABSTRACT: The natural history of anemia related to interferon/ribavirin (IFN/RBV) treatment in patients with human immunodeficiency virus/hepatitis C virus (HIV/HCV) coinfection is not completely understood. The current 8-week, multicenter, observational study characterized anemia over the course of HCV treatment in patients with HIV/HCV coinfection. Eligible HIV/HCV coinfected patients were receiving care in community-based and academic institutions and were on stable antiretroviral therapy and initiating IFN/RBV therapy. Hb, sEPO, reticulocytes, transfusions, laboratory values (e.g., total bilirubin), and IFN and RBV dosages were monitored weekly. Ninety-one patients were analyzed (mean age, 46 years; 71% on HAART) and 53 patients completed the study. Mean Hb decreased significantly (5.0 g/dl) within 1 week of initiating IFN/RBV therapy (p = 0.0002); Hb nadir occurred at a median of 37 days. Maximum Hb decreases of > or =2.0 g/dl occurred in 56 (62%) patients and > or =3.0 g/dl occurred in 45 (49%) patients. Reticulocyte count increased within the first 2 weeks and sEPO peaked at week 3. Mean increase from baseline to week 2 in reticulocyte count and sEPO, respectively, was 1.3% (n = 74) and 45.0 mIU/ml (n = 80) (p < 0.0001 for each parameter), and from baseline to week 8 was 0.9% (n = 48) and 41.0 mIU/ml (n = 52) (p < or = 0.0001 for each parameter). Adverse events (AEs) were the most common reason for study discontinuation (66% of discontinuing patients). Among the 25 patients who discontinued due to AEs, 84% discontinued due to anemia (n = 21). Significant decreases in Hb were observed in HIV/HCV-coinfected patients within 1 week of initiating IFN/RBV therapy. sEPO and reticulocyte increases were blunted in response to anemia; Hb levels did not return to baseline values and anemia was a frequent reason for discontinuing the study.
    AIDS Research and Human Retroviruses 01/2007; 23(1):1-9. · 2.71 Impact Factor
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    ABSTRACT: In hepatitis C virus (HCV)-infected patients receiving pegylated interferon (PEG-IFN)/ribavirin (RBV) combination therapy, anemia is a well-known side effect. The purpose of this study was to describe the time course and extent of hemoglobin (Hb) changes and the erythropoietic response to PEG-IFN/RBV-induced anemia. In this multicenter, observational, 8-wk study, laboratory parameters were measured weekly for 8 wk or until early withdrawal. Primary endpoints included changes in Hb and serum erythropoietin (sEPO) from baseline to week 8; other measures were changes in reticulocytes and RBV dose. The predictive value of baseline factors for maximum Hb decline was assessed. In the 97 evaluable patients, mean Hb decreased from 14.4 +/- 1.4 g/dl (baseline) to 11.9 +/- 1.3 g/dl (week 8). Twenty-one percent of patients withdrew before week 8. The estimated erythropoietic response was lower than that seen in two historic control populations of iron deficiency anemia patients. Mean RBV dose decreased from 986 +/- 190 mg/day (baseline) to 913 +/- 228 mg/day (week 8). Fifty-seven out of 77 (74%) patients who completed the study maintained their initial prescribed RBV dose. Patients maintained on the initial dose of RBV who had a higher baseline Hb and viral load showed a trend toward larger Hb declines. Platelets and white blood cells (WBCs) also declined during the study. HCV-infected patients receiving PEG-IFN/RBV therapy have reductions in Hb, platelets, and WBCs, possibly due to bone marrow suppression. They also have diminished endogenous sEPO production for their degree of anemia.
    The American Journal of Gastroenterology 03/2005; 100(2):299-307. · 9.21 Impact Factor
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    ABSTRACT: Anemia and decreased health-related quality of life (HRQL) are common in patients receiving combination therapy of interferon alfa (IFN) and ribavirin (RBV) for chronic hepatitis C virus (HCV) infection. In a randomized, prospective study evaluating the effectiveness of epoetin alfa in maintaining RBV dose, alleviating anemia, and improving HRQL in anemic (Hb < or = 12 g/dL) HCV-infected patients receiving combination therapy, patients receiving epoetin alfa had significant improvements in HRQL compared with placebo. In this study, 185 patients were randomized to 40,000 units of epoetin alfa subcutaneously weekly or placebo for an 8-week double-blind phase (DBP), followed by an 8-week open-label phase during which all patients received epoetin alfa. To further assess the impact of epoetin alfa on HRQL, post hoc analyses were conducted in the same patient population to compare the HRQL of these patients at randomization with norms of other populations, and to determine the critical relationship between hemoglobin (Hb) levels and HRQL. Mean HRQL scores of anemic HCV-infected patients receiving combination therapy at randomization were significantly lower than those of both the general population and patients who had other chronic conditions. Patients receiving epoetin alfa who had the greatest Hb increases from randomization to the end of the DBP also had the largest improvements in HRQL. Hb improvement was an independent predictor of HRQL improvement in these patients. In conclusion, epoetin alfa provided clinically significant HRQL improvement in HCV-infected patients receiving IFN/RBV therapy.
    Hepatology 12/2004; 40(6):1450-8. · 12.00 Impact Factor
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    ABSTRACT: This prospective, open-label, multicenter trial evaluated the effects of once-weekly (qw) epoetin alfa on quality of life (QOL) and hemoglobin (Hb) levels in anemic human immunodeficiency virus (HIV)-infected adult receiving antiretroviral therapy. A total of 650 patients with Hb < or = 11 g/dl received epoetin alfa 40,000 U qw subcutaneously, with dose escalation to 60,000 qw if Hb increase was <1 g/dl after 4 weeks. The linear Analog Scale Assessment (LASA) overall QOL score, LASA energy score, and LASA activity score each significantly improved from baseline to final measurement (p < 0.0001 for each parameter). Improvements in the Medical Outcomes Study (MOS)-HIV physical and mental health summary scores were also significant (p < 0.0001), and coincided with Hb increases. Mean Hb increased from baseline to final measurement by 2.5 g/dl (95% CI: 2.3, 2.6 g/dl; p < 0.0001). Objective hematological response rate, defined as a > or = 1 g/dl Hb increase from baseline to week 8, was 86%. Hemoglobin increased significantly in all subgroups of race, zidovudine use, CD4+ cell count, and viral load. Once-weekly epoetin alfa was well tolerated. Once-weekly epoetin alfa is effective in improving QOL and Hb measures.
    AIDS Research and Human Retroviruses 11/2004; 20(10):1037-45. · 2.71 Impact Factor
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    ABSTRACT: Combination therapy with interferon alpha (IFN-alpha) and ribavirin (RBV) or pegylated IFN-alpha (PEG-IFN-alpha)/RBV for chronic hepatitis C virus (HCV) infection often causes anemia, prompting RBV dose reduction/discontinuation. This study assessed whether epoetin alfa could maintain RBV dose, improve quality of life (QOL), and increase hemoglobin (Hb) in anemic HCV-infected patients. HCV-infected patients (n = 185) on combination therapy who developed anemia (Hb < or = 12 g/dL) were randomized into a U. S. multicenter, placebo-controlled, clinical trial of epoetin alfa, 40,000 U subcutaneously, once weekly vs. matching placebo. The study design used an 8-week, double-blind phase (DBP) followed by an 8-week, open-label phase (OLP), in which placebo patients were crossed over to epoetin alfa. At the end of the DBP, RBV doses were maintained in 88% of patients receiving epoetin alfa vs. 60% of patients receiving placebo (P < 0.001). Mean QOL scores at the end of the DBP improved significantly on all domains of the Linear Analog Scale Assessment (LASA) and on 7 of the 8 domains of the Short Form-36, version 2 (SF-36v2). Mean Hb increased by 2.2 +/- 1.3 g/dL (epoetin alfa) and by 0.1 +/- 1.0 g/dL (placebo) in the DBP (P < 0.001). Similar results were demonstrated in patients who switched from placebo to epoetin alfa in the OLP. Epoetin alfa was well tolerated; the most common adverse effects were headache and nausea. Epoetin alfa maintained RBV dose and improved QOL and Hb in anemic HCV-infected patients receiving combination therapy.
    Gastroenterology 05/2004; 126(5):1302-11. · 12.82 Impact Factor
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    ABSTRACT: Recombinant human erythropoietin (epoetin alfa) has been used in clinical settings for more than a decade. Its indications have expanded considerably from its original use as hormone therapy in the treatment of anemia in adults with chronic kidney disease. Since the introduction of epoetin alfa, a greater understanding of anemia pathophysiology and the interactions of erythropoietin, iron, and erythropoiesis has been elucidated. Anemia is now independently associated with increased mortality and disease progression. Potential survival benefits associated with correction of anemia in various patient populations are leading to consideration of earlier, more aggressive treatment of mild to moderate anemia with epoetin alfa. Moreover, this agent's therapeutic use may extend beyond currently accepted roles. Epoetin alfa is undergoing evaluation with promising results in a variety of new clinical settings, including anemia associated with congestive heart failure, ribavirin-interferon alfa treatment of hepatitis C virus infection, and critical illness. Preclinical studies also have established erythropoietin and its recombinant equivalent to be a pleiotropic cytokine with antiapoptotic activity and neuroprotective actions in the central nervous system. The therapeutic potential of epoetin alfa appears yet to be fully realized.
    Archives of Internal Medicine 03/2004; 164(3):262-76. · 11.46 Impact Factor
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    ABSTRACT: Anemia is prevalent in HIV-positive patients despite lower doses of zidovudine used in highly active antiretroviral therapy. Previously, epoetin alfa has been administered 3 times weekly (TIW). We compared the hematologic and quality of life (QOL) effects and tolerability of the more convenient once-weekly (QW) regimen with TIW epoetin alfa in anemic HIV-positive patients. Two hundred eighty-five anemic (hemoglobin [Hb] <12 g/dL) HIV-positive adults receiving stable antiretroviral therapy were enrolled in this 16-week, randomized, multicenter study. Enrolled patients were randomized to receive epoetin alfa doses of 40,000 to 60,000 U QW or 100 to 300 U/kg TIW. Two hundred seventy-two patients were evaluable for efficacy. Both epoetin alfa dosing schedules produced significant Hb level increases by week 2 (mean Hb increase of 1.3 g/dL [QW] and 1.0 g/dL [TIW]; P < 0.0001) that continued to increase until week 8 and were maintained until study completion, with no significant difference between treatment groups at final Hb measurement (mean Hb increase of 2.9 g/dL [QW] and 2.5 g/dL [TIW]). All QOL parameters improved significantly (P < 0.05) from baseline by week 8 in both groups, with no significant differences between groups at week 16. Both dosing schedules were well tolerated. QW dosing of epoetin alfa is as effective as TIW dosing in increasing Hb levels, which was associated with improved QOL in anemic HIV-positive patients. QW dosing should also offer added convenience for patients and caregivers.
    JAIDS Journal of Acquired Immune Deficiency Syndromes 12/2003; 34(4):368-78. · 4.65 Impact Factor
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    ABSTRACT: The aim of this study was to determine the efficacy of epoetin alfa in alleviating anemia and minimizing ribavirin (RBV) dose reductions in patients with chronic hepatitis C virus (HCV) infection receiving combination RBV/interferon alfa (IFN) therapy. HCV-infected patients who had Hb levels of 12 g/dl or less during the first 24 wk of combination RBV/IFN therapy (n=64) were randomized to treatment with epoetin alfa (40,000 units) s.c. q.w. or to standard of care (SOC) for anemia management (RBV dose reduction or discontinuation, transfusions). Primary and secondary efficacy endpoints were changes in Hb level and RBV dosage, respectively, from baseline to week 16 of epoetin alfa therapy. Based on intent-to-treat analysis, the mean changes from baseline Hb levels at week 16 were +2.8 g/dl for epoetin alfa versus +0.4 g/dl for SOC (p<0.0001), and the mean changes in RBV dosage were -34 mg/day for epoetin alfa versus -146 mg/day (p=0.060) for SOC. The mean Hb level at week 16 in the epoetin alfa group (13.8 g/dl) was significantly (p<0.0001) higher than that of the SOC group (11.4 g/dl). At week 4 and subsequently, significantly more patients in the epoetin alfa group did not have RBV dosage reductions (p<0.011). At study end, 83% of epoetin alfa-treated patients maintained RBV dosages of at least 800 mg/day, compared with 54% of patients receiving SOC (p=0.022). Epoetin alfa was well tolerated. In anemic HCV-infected patients treated with RBV/IFN, epoetin alfa increases Hb levels and maintains RBV dosing. Based on these results, epoetin alfa seems to be promising in the treatment of HCV treatment-related anemia. Further research is warranted to determine the potential impact on outcomes, including quality of life and sustained viral response rate.
    The American Journal of Gastroenterology 11/2003; 98(11):2491-9. · 9.21 Impact Factor
  • Gastroenterology 04/2003; 124(4). · 12.82 Impact Factor
  • Gastroenterology 01/2003; 124(4). · 12.82 Impact Factor