Predictors of severe haematological toxicity secondary to pegylated interferon plus ribavirin treatment in HIV HCV-coinfected patients

Transcription

1 Antiviral Therapy 12: Predictors of severe haematological toxicity secondary to pegylated interferon plus ribavirin treatment in HIV HCV-coinfected patients José A Mira 1, Luis F López-Cortés 2, Dolores Merino 3, Ana Arizcorreta-Yarza 4, Antonio Rivero 5, Antonio Collado 6, María J Ríos-Villegas 7, Mercedes González-Serrano 8, Manuel Torres-Tortosa 9, Juan Macías 1, Bárbara Valera-Bestard 2, Elisa Fernández-Fuertes 3, José A Girón-González 4, Fernando Lozano 10 and Juan A Pineda 10 * for the Grupo para el Estudio de las Hepatitis Víricas de la Sociedad Andaluza de Enfermedades Infecciosas (SAEI) 1 Unidad de Enfermedades Infecciosas, Servicio de Medicina Interna, Hospital Universitario de Valme, Sevilla, Spain 2 Servicio de Enfermedades Infecciosas, Hospital Universitario Virgen del Rocío, Sevilla, Spain 3 Servicio de Medicina Interna, Hospital Juan Ramón Jiménez, Huelva, Spain 4 Unidad de Enfermedades Infecciosas, Servicio de Medicina Interna, Hospital Universitario Puerta del Mar, Cádiz, Spain 5 Sección de Enfermedades Infecciosas, Hospital Universitario Reina Sofía, Córdoba, Spain 6 Servicio de Medicina Interna, Hospital Torrecárdenas, Almería, Spain 7 Unidad de Enfermedades Infecciosas, Hospital Universitario Virgen Macarena, Sevilla, Spain 8 Unidad de Enfermedades Infecciosas, Servicio de Medicina Interna, Hospital Universitario Virgen de la Victoria, Málaga, Spain 9 Sección de Enfermedades Infecciosas, Hospital Punta Europa, Algeciras, Spain 10 Unidad de Enfermedades Infecciosas, Hospital Universitario de Valme, Sevilla, Spain *Corresponding author: Tel: ; Fax: ; japineda@telefonica.net Background: Haematological adverse events related to pegylated interferon (PEG-IFN) and ribavirin (RBV) therapy could affect the patients quality of life; however, the risk factors for severe haematological toxicity associated with this therapy in patients coinfected with hepatitis C virus (HCV) and HIV are unclear. The objective of this study was to identify predictors of severe haematological toxicity among HIV HCV-coinfected patients treated with PEG-IFN plus RBV. Methods: This retrospective multicentric study included 237 HIV HCV-coinfected patients on PEG-IFN plus RBV. Predictors of severe anaemia, neutropenia, thrombocytopenia and overall haematological toxicity were analyzed. Results: Eighty (34%) individuals showed an episode of severe haematological toxicity. Severe anaemia, neutropenia and thrombocytopenia occurred in 32 (13%), 42 (18%) and 26 (11%) patients, respectively. In the multivariate analysis, zidovudine use (adjusted odds ratio [AOR] 3.3; 95% confidence interval [CI] ; P=0.001), baseline body weight <65 kg (AOR 2.5; 95% CI 1.1 5; P=0.024), cirrhosis (AOR 5; 95% CI ; P=0.006), PEG-IFN-α2a (AOR 2.7; 95% CI ; P=0.029) and pretreatment haemoglobin level <14 g/dl (AOR 2.7; 95% CI ; P=0.005) were associated with any kind of severe haematological toxicity. Likewise, haemoglobin level <13 g/dl, neutrophil counts <2,500 cells/mm 3 and platelet counts <175,000 cells/mm 3 were independent predictors of severe anaemia, neutropenia and thrombocytopenia, respectively. Conclusions: Zidovudine treatment, cirrhosis, baseline low body weight, use of PEG-IFN-α2a, and baseline haemoglobin level <14 g/dl are predictors of overall severe haematological toxicity secondary to PEG-IFN plus RBV in HIV-infected individuals. Low pretreatment levels of each haematological series predict a significant decrease of their values during therapy. Introduction The combination of pegylated interferon (PEG-IFN) plus ribavirin (RBV) is currently the treatment of choice for hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV) HCV-coinfected patients. Nevertheless, the rate of sustained virological response (SVR) to this antiviral therapy in coinfected individuals seems to be lower than that reached in HCV-monoinfected patients [1 8]. A worse tolerability of anti-hcv therapy, due to a higher rate of adverse events and drug interactions, could partially explain these differences among HIV HCV-coinfected individuals receiving antiretroviral therapy (ART). Side effects 2007 International Medical Press

2 JA Mira et al. related to PEG-IFN and RBV-based therapy can be treatment-limiting and require temporary or permanent dose reduction or premature discontinuation [1 4,9 12]. In addition, these side effects may be potentially severe and, therefore, affect the patients quality of life. Haematological adverse events are the most frequent laboratory abnormalities leading to dosage modifications or discontinuations during PEG-IFN plus RBV therapy in HIV HCV-coinfected individuals [1 4]. On the basis of data from pivotal clinical trials, 10 16% of HIV-infected patients require RBV dose reduction because of severe anaemia, whereas 7 27% need a dosage modification of PEG-IFN because of severe neutropenia [1,2,4]. Consequently, there is a need for further research to improve the prevention of these adverse events, particularly concerning the identification of factors that contribute to the development of severe haematological toxicity. To date, there is few data on the pretreatment risk factors associated with each type of haematological side effect in coinfected patients [12 15]. Likewise, the potential predictors of overall severe haematological adverse events associated with HCV therapy are unknown. In addition, it is not known how other factors, such as type of PEG-IFN given, liver fibrosis stage and other individual antiretroviral drugs, effect the appearance of severe haematological toxicity in HIV-infected patients receiving this antiviral combination. Other studies are needed to clarify these issues. The objective of the present study was to determine the predictors of severe haematological toxicity among HIV-infected patients with chronic hepatitis C treated with a combination of PEG-IFN plus RBV. Patients and methods Patients and follow up From October 2001 to February 2005, a cohort of 3,164 HIV HCV-coinfected patients older than 16 years of age was prospectively followed at nine university hospitals in Spain. Of these patients, 242 (8%) received HCV therapy with the combination of PEG- IFN plus RBV at some time during the follow up. All individuals included in this cohort were followed at least every 4 weeks during the first 24 weeks of treatment, and every 2 months during the remaining treatment period. Evaluation of adverse events, complete blood counts, and blood chemistries were carried out at every visit. Data were collected prospectively and entered in a database at each participating centre. All hospitals follow a similar protocol for recording adverse events related to PEG-IFN plus RBV treatment. Plasma HCV RNA was measured at least 12, 24 and 48 weeks after beginning therapy. After discontinuing therapy, individuals were followed for at least 6 months in order to assess SVR (undetectable serum HCV RNA 24 weeks after completion of treatment). Plasma HCV RNA was measured by PCR (Cobas Amplicor HCV Monitor, version 2.0, Roche Diagnostic System Inc., Branchburg, NJ, USA [detection limit 600 IU/ml] or Cobas AmpliPrep-Cobas Taqman, Roche Diagnostic System Inc., Meylan, France [detection limit 50 IU/ml]). To accomplish the goal of our study, HIV HCVcoinfected patients treated with PEG-IFN and RBV were included in a retrospective analysis if they fulfilled three pretreatment haematological criteria: i) a haemoglobin level >11 g/dl; ii) neutrophil counts >1,000 cells/mm 3 ; and iii) platelet counts >70,000 cells/mm 3. Treatment regimens All individuals received the combination of subcutaneous PEG-IFN-α2a at a dose of 180 μg/week or PEG-IFN-α2b at a dose of 1.5 μg/kg/week plus oral RBV at a dose of 800 1,200 mg/day. Temporary discontinuations and stepwise reductions in PEG-IFN and RBV dosage were not made following a similar protocol by all hospitals. Dose adjustments for both drugs were used according to the criteria of the caring physician. Treatment duration was 48 weeks for subjects harbouring HCV genotype 1 or 4, and 24 or 48 weeks for patients with HCV genotypes 2 or 3. At weeks 12 and 24, anti- HCV therapy was prematurely discontinued in nonresponding individuals. We considered as non-responders any patient who did not reach 2 log 10 reduction in HCV RNA levels at week 12 of treatment or undetectable serum HCV RNA 24 weeks after beginning therapy. During PEG-IFN plus RBV therapy, patients received ART according to the availability of drugs and the recommendations of international guidelines at the time of prescription. The use of granulocyte colonystimulating factor (G-CSF) and erythropoietin was available for all participating centres. Both growth factors were used to manage haematological adverse events, according to the criteria of the physician who was in charge of the patient. Assessment of overall severe haematological toxicity The main outcome variable was overall severe haematological toxicity, defined as the appearance of at least one of three laboratory abnormalities during PEG-IFN and RBV treatment: i) haemoglobin level <10 g/dl; ii) neutrophil counts <750 cells/mm 3 ; or iii) platelet counts <50,000 cells/mm 3. Statistical analysis The associations between overall severe haematological toxicity and different risk factors were analyzed. Likewise, predictors of anaemia, neutropenia and International Medical Press

3 Haematological toxicity related to HCV therapy thrombocytopenia were also assessed in several subanalyses. The following variables were included in these analyses: age, sex, body weight, CD4 + T-cell count and HIV RNA at baseline, use of individual antiretroviral drugs during HCV therapy, liver fibrosis stage according to the Scheuer s scoring system [16], type of PEG-IFN given, daily dose of RBV by weight and pretreatment haematological parameters. Continuous variables are expressed as median (interquartile range [IQR]) and categorical variables as a number (percentage). The Student s t-test was used for comparisons between continuous variables if a normal distribution was followed and the Mann Whitney U test if not. Frequencies were compared with the χ 2 test or the Fisher s test when appropriate. The parameters that showed a relationship with the outcome variables with a P<0.2 in the univariate analysis were entered in a multivariate stepwise logistic regression analysis. Associations with P<0.05 were considered significant. The adjusted odds ratio (AOR) and the respective 95% confidence interval (CI) were also calculated. The statistical analysis was carried out using the SPSS 14 statistical software package (SPSS; Chicago, Illinois, USA). Ethical aspects The study was designed and performed according to the Helsinki declaration and was approved by the Ethics committee of the Hospital Universitario de Valme. Results Characteristics of the study population Two-hundred and thirty-seven patients fulfilled the inclusion criteria. The main characteristics of these individuals are summarized in Table 1. Among the 90 patients harbouring HCV genotype 2 or 3, 30 (33%) received PEG-IFN and RBV for 24 weeks. ART was used concomitantly with HCV therapy in 198 (83%) individuals. SVR was reached in 88 (37%) subjects. Sixty-nine (38%) patients treated with PEG-IFN-α2a achieved SVR versus 19 (36%) out of those who received therapy with PEG-IFN-α2b. Eighteen (8%) subjects discontinued therapy against HCV due to their own decision and 29 (12%) due to side effects secondary to PEG-IFN and RBV treatment. Premature discontinuation of PEG-IFN and RBV treatment because of influenza-like syndrome and psychiatric symptoms occurred in 10 (4%) and 6 (2%) individuals, respectively. Outcome and predictors of overall severe haematological toxicity Eighty (34%) patients showed an episode of severe haematological toxicity during PEG-IFN plus RBV Table 1. Characteristics of the studied population (n=237) Parameter Value Age, years* 39 (35 42) Body weight, kg* 69 (60 76) Former IDU, n (%) 206 (87) CDC category C, n (%) 69 (29) HCV genotype 1 4, n (%) 147 (62) Baseline HCV RNA load, log IU/ml* 5.9 ( ) Baseline serum ALT, IU/l* 91 (58 136) Baseline cirrhosis, n (%) 34 (21) Type of PEG-IFN, n (%) α2a 184 (78) α2b 53 (22) RBV dose/weight, mg/kg* 13.9 ( ) Baseline CD4 + T-cell count, cells/ml* 532 ( ) Baseline undetectable HIV RNA viral load, n (%) 165 (70) Baseline haemoglobin level, g/dl* 15 ( ) Baseline neutrophil count, cells/mm 3 * 2,780 (2,157 3,785) Baseline platelet counts, cells/mm 3 * 174,000 (128, ,000) Use of zidovudine, n (%) 62 (26) Use of tenofovir, n (%) 57 (24) Use of stavudine, n (%) 66 (28) Use of abacavir, n (%) 57 (24) Use of didanosine, n (%) 18 (7) Protease inhibitor therapy, n (%) 86 (36) NNRTI therapy, n (%) 96 (40) *Median (interquartile range); Liver biopsy was available in 165 subjects; ALT, alanine aminotransferase; CDC, Center for Disease Control and Prevention; HCV, hepatitis C virus; IDU, intravenous drug user; PEG-IFN, pegylated interferon; RBV, ribavirin; NNRTI, non-nucleoside reverse transcriptase inhibitor. treatment. During the study period, 16 (7%) patients developed severe bycitopenia, whereas two (1%) individuals presented severe cytopenia in all three haematopoietic lineages. Four (2%) individuals were prematurely withdrawn from therapy because of severe haematological adverse events: one for neutropenia and three for anaemia. At the time of the discontinuation from PEG-IFN and RBV treatment due to anaemia, the levels of haemoglobin were 6, 7.3 and 9 g/dl. Among the individuals developing overall severe haematological toxicity, 56 (70%) experienced a dose reduction of PEG-IFN or RBV and 5 (6%) received G-CSF or erythropoietin alone, whereas the remainder did not use either of these strategies. Overall severe haematological toxicity was more frequently observed in patients who were treated with PEG-IFN-α2a than in those receiving PEG-IFN-α2b (Table 2). In the multivariate analysis, cirrhosis, antiretroviral regimens including zidovudine (AZT), baseline body weight <65 kg, baseline haemoglobin level <14 g/dl and the use of PEG-IFNα2a were independent predictors of overall severe haematological toxicity (Table 2). Antiviral Therapy 12:8 1227

4 JA Mira et al. Table 2. Predictors of overall severe haematological toxicity Severe haematological P-value Adjusted OR P-value Parameter toxicity, n (%) univariate (95% CI) multivariate Age, years (32) >39 42 (36) 0.5 Gender Male 61 (30) Female 19 (54) Body weight, kg (42) 2.5 (1.1 5) >65 38 (26) Liver cirrhosis Yes 18 (53) 5 ( ) No 41 (31) Dose of RBV, mg/kg (33) > (35) 0.8 Type of PEG-IFN α2a 69 (37) 2.7 ( ) αb 11 (21) Undetectable plasma HIV RNA Yes 62 (38) No 18 (25) CD4 + T-cell count, cells/mm (44) > (32) 0.2 Concomitant ART Yes 71 (36) No 9 (24) 0.1 Use of zidovudine* Yes 34 (55) 3.3 (1.6 10) No 37 (27) < Use of abacavir* Yes 19 (33) No 52 (37) 0.6 Use of tenofovir* Yes 16 (30) No 55 (38) 0.3 Use of stavudine* Yes 18 (27) No 53 (40) PI therapy* Yes 29 (34) No 42 (37) 0.5 NNRTI therapy* Yes 34 (35) No 37 (36) 0.9 Haemoglobin level, g/dl (57) 2.7 ( ) >14 43 (25) < Neutrophil count, cells/mm 3 2, (47) >2, (31) Platelet count, cells/mm 3 200, (40) >200, (19) *The percentages shown were calculated in the population who received antiretroviral therapy (ART). CI, confidence interval; OR, odds ratio; PEG-IFN, pegylated interferon; PI, protease inhibitor; RBV, ribavirin; NNRTI, non-nucleoside reverse transcriptase inhibitor International Medical Press

5 Haematological toxicity related to HCV therapy Outcome and predictors of severe anaemia Severe anaemia appeared in 32 (13%) patients. Because of this type of cytopenia, three (1%) individuals prematurely discontinued therapy against HCV. Among those subjects developing severe anaemia, RBV dose was temporarily or permanently reduced in 23 (72%) individuals, whereas three (13%) subjects received concomitantly erythropoietin. Eight (40%) out of 20 individuals who were receiving AZT changed this antiretroviral drug to another nucleoside reverse transcriptase inhibitor (NRTI) due to the appearance of severe anaemia. The median (IQR) level of baseline haemoglobin among patients who showed severe anaemia was 13.9 ( ) g/dl and among those who did not develop this adverse event was 15.2 ( ) g/dl (P<0.001). Severe anaemia and RBV dose reduction were more frequently observed in subjects treated with AZT than in individuals without AZT (Figure 1). Among those patients who received AZT, 4/11 (36%) individuals with CD4 + T-cell counts <300 cells/ml showed severe anaemia versus 16/51 (31%) individuals with CD4 + T-cell counts >300 cells/ml (P=0.7). Nineteen (16%) patients receiving a RBV daily dose >13.9 mg/kg showed severe anaemia, versus 13 (10%) subjects with an RBV dose below this level (P=0.1). The multivariate analysis revealed that a pretreatment haemoglobin level <13 g/dl, baseline body weight <65 kg and AZT use during HCV therapy were independent factors contributing to this type of haematological adverse event (Table 3). Outcome and predictors of severe neutropenia Severe neutropenia occurred in 42 (18%) individuals. Among these patients, 11 (26%) showed neutrophil counts <500 cells/mm 3. No patient had a decrease in the absolute neutrophil count <250 cells/mm 3 during therapy. Only one subject permanently discontinued HCV therapy because of severe neutropenia. Among those patients developing severe neutropenia, 25 (60%) experienced a dose reduction of PEG-IFN and 5 (12%) received G-CSF alone. None of the two individuals who developed bacterial infections had a neutrophil count <750 cells/mm 3 during the study period. Subjects with and without severe neutropenia had median (IQR) baseline neutrophil counts of 2,420 (1,817 2,780) cells/mm 3 and 2,995 (2,245 4,082) cells/mm 3 (P=0.002), respectively. Nine (22%) patients with severe neutropenia and 13 (8%) individuals without this adverse event received nevirapine (NVP) (P=0.01). Among those patients who received NVP, the pretreatment median (IQR) levels of neutrophils were 2,495 (2,125 3,577) cells/mm 3, whereas among those subjects who were not treated with this non-nucleoside reverse transcriptase inhibitor (NNRTI) levels were 2,780 (2,110 3,980) cells/mm 3 (P=0.077). In the Figure 1. Rate of severe anaemia and ribavirin dose reduction according to zidovudine (AZT) use (P<0.01 for each comparison) Percentage of cases multivariate analysis, baseline neutrophil counts <2,500 cells/mm 3, NVP use and baseline body weight <65 kg were independently associated with risk of development of severe neutropenia (Table 4). Outcome and predictors of severe thrombocytopenia Twenty-six (11%) patients presented severe thrombocytopenia. As a consequence of this, PEG-IFN dosage was reduced in 18 (69%) individuals. No patient developed a haemorrhagic event because of severe thrombocytopenia. The median (IQR) pretreatment platelet counts among subjects who developed severe thrombocytopenia were 111,000 (84, ,250) cells/mm 3 and among those who did not show it were 179,000 (147, ,000) cells/mm 3 (P<0.001). In the multivariate analysis, cirrhosis and pretreatment platelet counts <175,000 cells/mm 3 were independent predictors of severe thrombocytopenia (Table 5). Discussion 32 Severe anaemia AZT-based therapy Non AZT-based therapy Ribavirin dose reduction The results reported here demonstrate that low baseline haemoglobin level, low pretreatment body weight, liver cirrhosis, AZT-based therapy, and the use of PEG-IFNα2a are predictors of overall severe haematological toxicity secondary to HCV therapy among HIVinfected patients with chronic hepatitis C. Likewise, low pretreatment levels of each haematological line predict a significant decrease of their values during PEG-IFN plus RBV combination therapy. The rate of haematological adverse events observed in this study is in the range previously reported in clinical trials in the HIV-infected population [1,2]. Moreover, overall findings of severe haematological toxicity in this study seem to be very much in agreement with the results found in PRESCO, a recent prospective study conducted in HIV HCV-coinfected individuals using Antiviral Therapy 12:8 1229

6 JA Mira et al. Table 3. Factors associated with severe anaemia Severe P-value Adjusted OR P-value Parameter anaemia, n (%) univariate (95% CI) multivariate Age, years (11) >39 19 (16) 0.2 Gender Male 24 (12) Female 8 (23) Body weight, kg (24) 5 (1.6 10) >65 10 (7) < Liver cirrhosis Yes 5 (15) No 13 (13) 0.7 Dose of RBV, mg/kg (10) > (16) Type of PEG-IFN α2a 27 (15) α2b 5 (9) 0.3 Undetectable plasma HIV RNA Yes 26 (16) No 6 (8) CD4 + T-cell count, cells/mm (18) > (13) 0.4 Concomitant ART Yes 30 (15) No 2 (5) 0.1 Use of zidovudine* Yes 20 (32) 10 ( ) No 10 (7) <0.001 <0.001 Use of abacavir* Yes 9 (16) No 21 (15) 0.8 Use of tenofovir* Yes 4 (7) No 26 (18) Use of stavudine* Yes 5 (8) No 25 (19) PI therapy* Yes 8 (9) No 22 (20) NNRTI therapy* Yes 16 (17) No 14 (14) 0.5 Haemoglobin level, g/dl 13 9 (47) 4.6 ( ) >13 23 (11) < Neutrophil count, cells/mm 3 2,000 5 (11) - >2, (14) 0.5 Platelet count, cells/mm 3 200, (16) >200,000 5 (7) *The percentages shown were calculated in the population who received antiretroviral therapy (ART). CI, confidence interval; OR, odds ratio; PEG-IFN, pegylated interferon; PI, protease inhibitor; RBV, ribavirin; NNRTI, non-nucleoside reverse transcriptase inhibitor International Medical Press

7 Haematological toxicity related to HCV therapy Table 4. Factors associated with severe neutropenia Severe neutropenia P-value Adjusted OR P -value Parameter n, (%) univariate (95% CI) multivariate Age, years (15) >39 24 (20) 0.3 Gender Male 30 (15) Female 12 (34) Body weight, kg (25) 2.4 (1.1 5) >65 19 (13) Liver cirrhosis Yes 10 (29) No 24 (18) Type of PEG-IFN α2a 36 (20) α2b 6 (11) Undetectable plasma HIV RNA Yes 35 (21) No 7 (10) CD4 + T-cell count, cells/mm (26) > (17) 0.2 Concomitant ART Yes 40 (20) No 2 (5) 0.02 Use of zidovudine* Yes 17 (27) No 23 (17) Use of abacavir* Yes 10 (17) No 30 (21) 0.5 Use of tenofovir* Yes 9 (17) No 31 (25) 0.4 Use of stavudine* Yes 12 (18) No 28 (21) 0.6 PI therapy* Yes 18 (21) No 22 (20) 0.8 Use of nevirapine* Yes 9 (41) 3.1 ( ) No 31 (17) Haemoglobin level, g/dl (23) >14 23 (13) Neutrophil count, cells/mm 3 2, (27) 3.3 (1.4-10) >2, (12) Platelet count, cells/mm 3 200, (20) >200,000 8 (12) *The percentages shown were calculated in the population who received antiretroviral therapy (ART). CI, confidence interval; OR, odds ration; PEG-IFN, pegylated interferon; PI, protease inhibitor. Antiviral Therapy 12:8 1231

8 JA Mira et al. weight-based RBV therapy [17]. Likewise, the rates of each kind of haematological adverse event are similar to those found in HCV-monoinfected patients, except for thrombocytopenia, which was more frequent in our study population [6 8]. By contrast, this is the first study, to our knowledge, in which the relationship between several risk factors and the development of overall severe haematological events has been assessed in HIV HCV-coinfected patients treated with PEG-IFN plus RBV in daily clinical practice. Our results provide relevant information regarding factors that contribute to the appearance of at least one haematological side effect in this population, such as cirrhosis and low body weight. Moreover, PEG-IFN-α2a has been found to be associated with a higher rate of severe haematological adverse events during HCV therapy, a finding that has not been previously reported in coinfected patients. In this study, PEG-IFN-α2a tended to be related to higher decreases in neutrophil and platelet counts compared with PEG- IFN-α2b, although these differences did not reach statistical significance probably due to a lack of statistical power. Other studies comparing both PEG- IFN preparations have shown similar results in HCVmonoinfected patients, specifically a greater reduction in the absolute neutrophil count among individuals receiving PEG-IFN-α2a [18,19]. There is no explanation of this finding, although it has been suggested that it could be attributed to differences in pharmacokinetic properties between the two pegylated formulations [19]. The biochemical properties of PEG-IFN-α2a, that is, a larger molecular weight and a more restricted volume of distribution to extravascular space, could support the higher serum concentrations observed with PEG-IFN-α2a compared with PEG-IFN-α2b [20]. This different drug exposure might explain the higher rate of severe haematological events observed with PEG- IFN-α2a in our study. In any case, according to the results of our study, the rate of SVR achieved with both PEG-IFN preparations is comparable. Therefore, it suggests that the higher frequency of severe haematological events associated with the use of PEG-IFN-α2a does not have a significant effect on the efficacy of HCV therapy. Because of possible biases related to the retrospective design of this study, this association needs to be confirmed by randomized clinical trials. In this study, severe anaemia and RBV dose reduction were associated with antiretroviral regimens including AZT, which is consistent with other studies in HIVcoinfected populations [12,14,15]. In this sense, it has been suggested that an additive myelosuppresive effect of PEG-IFN plus AZT could inhibit the haematopoietic response to RBV-induced haemolysis [21,22]. Due to this increased rate of RBV dose reduction caused by AZT use, HCV therapy could be less effective among individuals taking this antiretroviral drug [23]. A recent study performed in our cohort of HIV HCV-coinfected patients treated with PEG-IFN and RBV has demonstrated that subjects without concomitant ART and those receiving combinations of a protease inhibitor or an NNRTI with a nucleos(t)ide backbone of tenofovir or stavudine plus lamivudine respond better than those receiving other ART combinations, including AZTbased ART [24]. As a consequence, AZT should be changed to another NRTI before initiating treatment with PEG-IFN and RBV. Based on the latest international guidelines for the care of HIV HCV-coinfected patients [25], which recommend the use of erythropoietin in individuals developing anaemia secondary to RBV, when other NRTI options are not possible, clinicians should consider starting this growth factor. The use of erythropoietin may help to maintain and/or increase haemoglobin level and allow completion of the planned RBV dose in subjects receiving concomitant AZT-based therapy [26,27]. Other pretreatment predictors of severe anaemia reported in this work, such as low haemoglobin level and body weight, have been previously reported in HCV-monoinfected or HIV HCV-coinfected patients [12,13,27 29]. Likewise, we did not find associations between RBV daily dose per kilogram of body weight and severe anaemia, in agreement with other studies [12,15,30]. Nevertheless, it has been reported that RBV plasma concentrations could play a role in the development of this haematological adverse event [30 32]. With respect to neutropenia, the results of this work provide information about different aspects. Owing to the potential risk of infectious complications, the pharmaceutical package insert for the two different formulations of PEG-IFN recommends dose reduction and permanent discontinuation of this antiviral if the absolute neutrophil count falls <750 cells/mm 3 and <500 cells/mm 3, respectively. In addition, international recommendations of consensus panels for the management and treatment of HIV HCV-coinfected patients suggest that G-CSF might be considered to counter the neutropenia when dose reduction of PEG-IFN has failed [33]. However, in our work, none of the subjects who showed a decrease in the absolute neutrophil count <750 cells/mm 3 had bacterial infections during HCV therapy. This finding is in agreement with other works both in HCV-monoinfected individuals and in HIV-coinfected populations, as well as with recent guidelines for managing HIV HCV coinfection [1 4,12,25,27,34]. Therefore, in our opinion, larger controlled clinical trials are warranted to assess the usefulness of G-CSF treatment in coinfected patients with neutropenia. Unexpectedly, we found that the use of antiretroviral regimens including NVP was associated with an International Medical Press

9 Haematological toxicity related to HCV therapy Table 5. Factors associated with severe thrombocytopenia Severe thrombocytopenia, P-value Adjusted OR P-value Parameter n (%) univariate (95% CI) multivariate Age, years (8) 0.2 >39 16 (14) Gender Male 23 (11) 0.6 Female 3 (8) Body weight, kg (13) 0.4 >65 14 (10) Liver cirrhosis Yes 10 (29) < ( ) 0.01 No 7 (5) Type of PEG-IFN α2a 24 (13) α2b 2 (4) Undetectable plasma HIV RNA Yes 17 (10) 0.6 No 9 (12) CD4 + T-cell count, cells/mm (11) 0.9 > (11) Concomitant ART Yes 21 (11) 0.6 No 5 (13) Use of zidovudine* Yes 5 (8) 0.4 No 16 (12) Use of abacavir* Yes 6 (11) 0.9 No 15 (11) Use of tenofovir* Yes 8 (15) 0.2 No 13 (9) Use of stavudine* Yes 9 (14) 0.3 No 12 (9) PI therapy* Yes 10 (12) 0.6 No 11 (10) NNRTI therapy* Yes 7 (7) No 14 (13) Haemoglobin level, g/dl (20) >14 13 (8) Neutrophil count, cells/mm 3 2,000 9 (19) >2, (9) Platelet count, cells/mm 3 175, (15) (2 25) 0.02 >175,000 1 (1) *The percentages shown were calculated in the population who received antiretroviral therapy (ART). CI, confidence interval; OR, odds ratio; PEG-IFN, pegylated interferon; PI, protease inhibitor; NNRTI, non-nucleoside reverse transcriptase inhibitor. Antiviral Therapy 12:8 1233

10 JA Mira et al. increased rate of severe neutropenia during therapy against HCV. This finding, to our knowledge, has not been previously reported in HIV-infected patients treated with PEG-IFN plus RBV. However, we cannot totally exclude that lower pretreatment neutrophil counts among those individuals receiving NVP-based ART could be the cause of the higher frequency of severe neutropenia. Moreover, although PEG-IFN and NVP can produce neutropenia, significant interactions between these drugs have been not reported so far [35]. Therefore, we think that the relationship between the use of NVP and severe neutropenia observed in this study may be due to distinct unnoticed biases. This study has some limitations. First, despite the fact that our study included a large sample size, we cannot exclude that it was too small to detect some differences that otherwise could have been observed, such as the possible relationship between neutropenia or thrombocytopenia and the use of PEG-IFN-α2a. Second, our study was performed retrospectively. This could have led to unnoticed bias. Nevertheless, the rates of severe haematological adverse events in the present study were in the range of those observed in randomized clinical trials carried out in HIV HCV-coinfected patients treated with HCV therapy [1 4,17], which suggest that the potential biases might not have been relevant. Finally, we cannot exclude that an extended duration of HCV therapy, exactly 48 weeks, in the group of patients harbouring HCV genotype 2 or 3 who were treated for only 24 weeks might have resulted in a higher rate of severe haematological side effects. In summary, on the basis of our results, those HIV HCV-coinfected patients with liver cirrhosis, those who have low body weight, and those with low haematological values prior to initiating PEG-IFN plus RBV should be more carefully monitored for haematological laboratory abnormalities during HCV therapy. Likewise, AZT use should be discontinued before starting this antiviral combination in individuals with alternative antiretroviral options. Larger controlled clinical trials are needed to confirm the relationship between the use of PEG-IFN-α2a and more frequent severe haematological adverse events in the HIV-infected population. Acknowledgements This study has been partly supported by grants from the Consejería de Salud of the Junta de Andalucía (Reference: 44/05), the Fondo de Investigaciones Sanitarias (FIS) (Reference: PI ) and the ISCIII-RETIC RD06/006. References 1. Torriani FJ, Rodríguez-Torres M, Rockstroh JK, et al. Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection in HIV-infected patients. N Engl J Med 2004; 351: Carrat F, Bani-Sadr F, Pol S, et al. Pegylated interferon alfa- 2b, plus ribavirin, for chronic hepatitis C in HIV-infected patients. A randomized controlled trial. JAMA 2004; 292: Chung RT, Andersen J, Volberding P, et al. Peginterferon alfa-2a plus ribavirin versus interferon alfa-2a plus ribavirin for chronic hepatitis C in HIV-coinfected persons. N Engl J Med 2004; 351: Laguno M, Murillas J, Blanco JL, et al. Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for treatment of HIV/HCV co-infected patients. AIDS 2004; 18:F27 F Mira JA, Torre-Cisneros J, Merino D, et al. Efficacy of pegylated interferon plus ribavirin in HIV/HCV co-infection outside of well-circumscribed clinical trials: The Andalusian multicenter study. 13th Conference on Retroviruses and Opportunistic Infections. 5 9 February 2006, Denver, CO, USA. Abstract Manns MP, McHutchinson JG, Gordon SC, et al. Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for initial treatment of chronic hepatitis C: a randomized trial. Lancet 2001; 358: Fried MW, Shiffamn ML, Reddy KR, et al. Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection. N Engl J Med 2002; 347: Hadziyannis SJ, Sette H, Morgan TR, et al. Peginterferona2a and ribavirin combination therapy in chronic hepatitis C. A randomized study of treatment duration and ribavirin dose. Ann Intern Med 2004; 140: Bani-Sadr F, Carrat F, Pol S, et al. Risk factors for symptomatic mitochondrial toxicity in HIV/Hepatitis C virus-coinfected patients during interferon plus ribavirinbased therapy. J Acquir Immune Defic Syndr 2005; 40: Laguno M, Blanch J, Murillas J, et al. Depressive symptoms after initiation of interferon therapy in human immunodeficiency virus-infected patients with chronic hepatitis C. Antivir Ther 2004; 9: Mauss S, Valenti W, DePamphilis J, et al. Risk factors for hepatic decompensation in patients with HIV/HCV coinfection and liver cirrhosis during interferon-based therapy. AIDS 2004; 18:F21 F Fuster D, Huertas JA, Gómez G, et al. Baseline factors associated with haematological toxicity that leads to a dosage reduction of pegylated interferon-α2a and ribavirin in HIV- and HCV-coinfected patients on HCV antiviral therapy. Antivir Ther 2005; 10: Pau AK, McLaughlin MM, Hu Z, et al. Predictors for hematopoietic growth factors use in HIV/HCV-coinfected patients treated with peginterferon alfa-2b and ribavirin. AIDS Patient Care and STDs 2006; 20: Brau N, Rodriguez-Torres M, Prokupek D, et al. Treatment of chronic hepatitis C in HIV/HCV coinfection with interferon alpha-2b + full-course vs. 16-week delayed ribavirin. Hepatology 2004; 34: Alvarez D, Dieterich DT, Brau N, Moorehead L, Ball L, Sulkowski MS. Zidovudine use but not weight-based ribavirin dosing impacts anaemia during HCV treatment in HIV-infected persons. J Viral Hepat 2006; 13: Scheuer PJ. Classification of chronic viral hepatitis: a need for reassessment. J Hepatol 1991; 13: Soriano V, Miralles C, Berdún MA, et al. Premature treatment discontinuation in HIV/HCV-coinfected patients receiving pegylated interferon plus weight-based ribavirin. Antivir Ther 2007; 12: Silva M, Poo V, Wagner F, et al. A randomised trial to compare the pharmacokinetic, pharmacodynamic, and antiviral effects of peginterferon alfa-2b and peginterferon alfa-2a in patients with chronic hepatitis C (COMPARE). J Hepatology 2006; 45: Schmid M, Kreil A, Jessner W, et al. Suppression of haematopoiesis during therapy of chronic hepatitis C with different interferon a mono and combination therapy regimens. Gut 2005; 54: International Medical Press

11 Haematological toxicity related to HCV therapy 20. Bruno R, Sacchi P, Ciappina V, et al. Viral dynamics and pharmacokinetics of peginterferon alpha-2a and peginterferon alpha-2b in naive patients with chronic hepatitis C: a randomised, controlled study. Antivir Ther 2004; 9: Dainiak N, Worthington M, Riordan MA, Kreczbo S, Goldman L. 3 -Azido-3 -deoxythymidine (AZT) inhibits proliferation in vitro of human haematopoietic progenitor cells. Br J Haematol 1998; 69: De Franceschi L, Fattovich G, Turrini F, et al. Hemolytic anemia induced by ribavirin therapy in patients with chronic hepatitis C virus infection: role of membrane oxidative damage. Hepatology 2000; 31: Opravil M, Torriani F, Sasadeusz J, et al. Treatment exposure and sustained virologic response (SVR) in genotype 1 patients treated with peginterferon alfa-2a (40kd) (Peg Ifna2a) + ribavirin (RBV) in Apricot. 45th International Conference on Antimicrobial Agents and Chemotherapy December 2005, Washington, DC, USA. Abstract V Mira JA, Carrillo-Gómez R, Gutiérrez-Valencia A, et al. Antiretroviral regimens including tenofovir or stavudine plus lamivudine as NRTI backbone are associated with higher sustained virological response rate to pegylated interferon and ribavirin treatment in HIV/HCV-coinfected patients. 14th Conference on Retroviruses and Opportunistic Infections February 2007, Los Angeles, CA, USA. Abstract Soriano V, Puoti M, Sulkowski M, et al. Care of patients coinfected with HIV and hepatitis C virus: 2007 updated recommendations from HCV-HIV International Panel. AIDS 2007; 21: Sulkowski MS, Dieterich BT, Bini EJ, et al. Epoetin alfa once weekly improves anemia in HIV/hepatitis C virus-coinfected patients treated with interferon/ribavirin: a randomized controlled trial. J Acquir Immune Defic Syndr 2005; 39: Lebray P, Nalpas B, Vallet-Pichard A, et al. The impact of haematopoietic growth factors on the management and efficacy of antiviral treatment in patients with hepatitis C virus. Antivir Ther 2005; 10: Accepted for publication 8 August Hung CH, Lee CM, Lu SN, et al. Anemia associated with antiviral therapy in chronic hepatitis C: incidence, risk factors, and impact on treatment response. Liver Int 2006; 26: Takaki S, Tsubota A, Hosaka T, et al. Factors contributing to ribavirin dose reduction due to anemia during interferon alfa2b and ribavirin combination therapy for chronic hepatitis C. J Gastroenterol 2004; 39: Rendón A, Núñez M, Romero M, et al. Early monitoring of ribavirin plasma concentrations may predict anemia and early virologic response in HIV/hepatitis C viruscoinfected patients. J Acquir Immune Defic Syndr 2005; 39: Dominguez S, Cassard B, Duvivier C, et al. Early therapeutic drug monitoring of ribavirin predicts anemia and early virological response in HIV/HCV-coinfected patients. 14th Conference on Retroviruses and Opportunistic Infections February 2007, Los Angeles, CA, USA. Abstract Aguilar Marucco D, Gonzalez de Requena D, Veronese L, et al. Cut-off values of ribavirin trough concentration for sustained virological response and for haematological toxicity in HCV/HIV-co-infected patients treated with ribavirin and pegylated interferon. 14th Conference on Retroviruses and Opportunistic Infections February 2007, Los Angeles, CA, USA. Abstract Tien PC. Management and treatment of hepatitis C virus infection in HIV-infected adults: recommendations from the veterans affairs hepatitis C resource center program and national hepatitis program office. Am J Gastroenterol 2005; 100: Cooper CL, Al-Bedwawi S, Lee C, Garber G. Rate of infectious complications during interferon-based therapy for hepatitis C is not related to neutropenia. Clin Infect Dis 2006; 42: Perronne C. Antiviral hepatitis and antiretroviral drug interactions. J Hepatol 2006; 44: Antiviral Therapy 12:8 1235

12