Interferon β-1b Therapy in Chronic Viral Dilated Cardiomyopathy—Is There a Role for Specific Therapy?

Journal of Cardiac Failure Vol. 16 No. 4 2010

Basic Science and Experimental Studies

Interferon b-1b Therapy in Chronic Viral Dilated CardiomyopathydIs There a Role for Specific Therapy? OLIVER ZIMMERMANN, MD,1,* CHRISTOPH RODEWALD, MD,1,* MICHAEL RADERMACHER, MD,1 MARTIN VETTER,1 JULIANE M. WIEHE, PhD,1 MAGDALENA BIENEK-ZIOLKOWSKI,1 VINZENZ HOMBACH, MD,1 AND JAN TORZEWSKI, MD2 Ulm, Germany; Immenstadt, Germany

ABSTRACT Background: Myocardial biopsy can be used for the detection of viral genome in dilated cardiomyopathy (DCM). Pilot studies have previously reported beneficial effects on clinical outcome and safety of an antiviral therapy using interferon b-1b in chronic viral DCM. Methods and Results: Myocardial biopsies were taken from patients with DCM. Using polymerase chain reaction and Southern Blot analysis, viral genome could be detected in 49% of patients. In 42 patients with viral infection, off-label use with interferon b-1b was initiated. A further 68 patients formed the control group. The outcome was evaluated after follow-up with echocardiography, exercise electrocardiogram, and New York Heart Association class. A total of 81 men and 29 women with a median left ventricular ejection fraction of 34% were included. The follow-up period was 36 months. In 33 (79%) patients with interferon b-1b treatment, minor adverse reactions occurred, but no major adverse events were reported. No significant benefit for interferon b-1b treatment on clinical outcome could be detected during follow-up. Conclusions: Off-label use with interferon b-1b in patients with viral DCM is feasible and safe under routine clinical practice. Concerning the herein evaluated clinical outcome parameters, promising results from pilot studies could not be confirmed. High prevalence of parvovirus B19 (92%) might influence the results. (J Cardiac Fail 2010;16:348e356) Key Words: Virus, biopsy, heart failure, outcome, interferon b-1b.

inflammation resulted in a series of studies to determine whether immunosuppressive therapy improves left ventricular function in patients with acute and chronic myocarditis. These studies reported heterogeneous results as analysis of inflammation was limited to histomorphological criteria only. Furthermore, before application of immunosuppressive therapy, persisting viral genomes were not excluded.10e12 Consequently, clinical outcome may have been impaired by a potential increase of virus load under immunosuppression. During the last decade, the light microscopical Dallas criteria13 of myocarditis were expanded by new molecular biological techniques, which provided novel insights to etiology and epidemiology of cardiac dysfunction. Viral infection of the myocardium is now considered to be the most common cause of chronic DCM resulting from acute myocarditis.14,15 In about 50% of idiopathic DCM, chronic virus persistence in the myocardium has been detected, and these patients seem to show a poorer prognosis.15e17 Adeno- and enteroviruses are known as classical cardiotropic pathogens in acute myocarditis and subsequent chronic DCM, and can be detected in about 10% of viral

Dilated cardiomyopathy (DCM) represents a chronic myocardial disease with poor prognosis.1e3 Established heart failure treatment consists of drug therapies and implantable devices.4 For selected patients surgical procedures, in which heart transplantation represents an ultimate step, complete the spectrum. Despite all progress, therapeutic options in advanced heart failure are limited and for most subtypes of DCM, causal treatment is still not available. Myocardial biopsy was introduced as a powerful tool for differential diagnosis in DCM.5e9 Detection of myocardial From the 1Department of Internal Medicine II - Cardiology, University of Ulm, Ulm, Germany and 2Herz- und Gefa¨ß-Zentrum Oberallga¨u, Klinik Immenstadt, Immenstadt, Germany. Manuscript received January 23, 2009; revised manuscript received October 22, 2009; revised manuscript accepted December 17, 2009. Reprint requests: Dr. Oliver Zimmermann, University of Ulm, Department of Internal Medicine II-Cardiology, Albert-Einstein-Allee 23, 89081 Ulm, Germany. Tel.: þ49 731 500- 45090; Fax: þ49 731 50045005. E-mail: [email protected] Supported in part by the Deutsche Stiftung fu¨r Herzforschung. * Both authors contributed equally to this work. 1071-9164/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.cardfail.2009.12.016

348

Interferon b-1b in Viral Cardiomyopathy

DCM.14 In the late 1990s, parvovirus B19 was added and could be detected in up to 50% of DCM. Its high prevalence and probably a different pathomechanism, pathogenicity, and response to interferons may lead to a discrete role among other cardiotropic viruses.18e22 Today, human herpes virus (HHV) 6 represents a novel player and increasing prevalence is being reported.23 In contrast, viruses such as cytomegalovirus, herpes simplex virus, Epstein-Barr virus, or influenza A and B virus are only rarely found within the myocardium in DCM patients.23 The new diagnostic insights gained by extended biopsy analysis provided a basis for novel therapeutic strategies and prognostic considerations.5e9 Several attempts for specific treatment of chronic DCM have been described (ie, immunosuppressants, immunoglobulins, immunomodulators, and antivirals).11,12,24e26 In 2003, a phase I study demonstrated safety for treatment of DCM with myocardial enteroor adenoviral infection with interferon b-1b.27 In all patients (n 5 22), the viral genome was completely eliminated. In 15 patients, an improvement of left ventricular function was reported. Between 2002 and 2005, a European, randomized, placebo-controlled, double-blinded, multicenter phase II study (BICC trial) was performed to evaluate safety and effectiveness of interferon b-1b in chronic viral cardiomyopathy. The first results were reported at the American Heart Association scientific sessions in 2008. Interferon b-1b treatment led to a significant reduction/elimination of viral load with some evidence of clinical improvement. This study indicated for the first time that a biopsy-based specific and causal therapy is possible for this condition.28 In the present study, patients suffering from chronic viral DCM received specific therapy with interferon b-1b. Whereas former studies focused on elimination or reduction of viral genome in the myocardium of a selected study population, the primary aim of our study addressed clinical outcome and safety/feasibility of a specific therapy under routine clinical practice. Secondarily, the potential benefit of a specific treatment with interferon b-1b versus conventional heart failure therapy was evaluated retrospectively. Materials and Methods Patients A total of 110 patients with chronic viral DCM admitted to Ulm University Medical Center between 1999 and 2008 were included. Almost all patients were Caucasian. Essential inclusion criteria consisted of a reduced left ventricular function (ejection fraction !60%) and the detection of viral genome in myocardial biopsy specimens. Inclusion criteria have been described in detail elsewhere.29 In brief, exclusion criteria for biopsy and interferon b-1b therapy included coronary artery disease, valvular disease, obstructive or restrictive cardiomyopathy, uncontrolled arrhythmias, significant hepatic, renal, pulmonary or endocrine disease, a history of depression, drug or alcohol abuse, hypersensitivity to human proteins including interferons, intolerance to paracetamol or other analgetics, pregnancy or lactation, and antiviral therapy within 6 months before enrollment. Patients were in a cardiopulmonary stable condition without episodes of



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decompensated heart failure within the preceding 2 months. Furthermore, patients with serious viral or bacterial infections within the last 4 weeks were excluded. Acute myocarditis was excluded clinically by physical examination, lack of newly developed electrocardiogram (ECG) changes and blood analysis. Blood samples (EDTA plasma) taken during myocardial biopsy were available for all patients since 2005. Within the first years (1999 to 2004), our routine viral analysis included the most common and established types of myocardial virus (ie, adeno- and enterovirus). Later, HHV6 and parvovirus B19 (PVB19) were introduced as novel players for myocardial infection.15,17e20,23,39 Consequently, we considered these reports and extended our virus analysis by inclusion of HHV6 and PVB19 since 2005. For this study, we additionally analyzed patients included between 1999 and 2004 (n 5 153) for presence of myocardial HHV6 and PVB19. In 58 patients, for who viral infection with entero- and adenovirus was initially excluded, we could now detect HHV6 or PVB19. In 4 patients, for whom initially entero- or adenovirus could be detected, we were now able to detect a simultaneous infection with HHV6 or PVB19 (Table 1). The newly diagnosed patients were considered in the negative control, as we were not able to refer them to interferon b-1b therapy based on a myocardial biopsy that was taken a couple of years ago. Consequently a significantly longer follow-up period could be observed for the control group compared to the interferon b-1b group (Table 2). All procedures were performed in accordance with ethical standards, and patients gave written informed consent. Approval was Table 1. Recruitment of the Study Population Patients

n

Total number of biopsies Virus detection: Adenovirus Enterovirus HHV6 PVB19 Simultaneous viral infection Patients excluded because of other myocardial pathology: Sarcoidosis Amyloidosis Graft vs. host disease Acute myocarditis Autoimmune disease Tuberculosis Patients excluded because of follow-up !6 months Study population: With interferon b-1b therapy Control group

273 (49%) (0.7%) (11%) (4%) (92%) (8%) (7%) (20%) (20%) (10%) (30%) (10%) (10%) (11%) 110 42 (38%) 68 (62%)

135 1 15 6 124 11 10 2 2 1 3 1 1 15

Prevalence of viral genome in the study population

Adenovirus Enterovirus HHV6 PVB19 Simultaneous infection No PVB19 infection

IFN b-1b group

Control group

P

1 6 1 38 4 4

0 7 5 63 7 5

.81 .74 .49 .96 .84 .96

HHV, human herpes virus 6; PVB, parvovirus B19; IFN, interferon. Between 1999 and 2008, myocardial biopsies were performed in 273 patients. Simultaneous viral infection was detected with 2 different kinds of viruses in 11 patients. As a result of simultaneous infection, the percentage for viral subgroup analysis exceeds 100%. For comparison of viral subgroup analysis between the interferon b-1b and control groups, chi-square test was calculated.

350 Journal of Cardiac Failure Vol. 16 No. 4 April 2010 Table 2. Major Characteristics of the Study Population at Baseline Visit IFN b-1b Group (n 5 42)

Control Group (n 5 68)

P

50 (20-73) 74% : 26% 27 (14-40) 3 (2-7)

55 (20-73) 74% : 26% 27 (16-41) d

.01 .85 1.00 d

12 (6-96) 32 (11-57) 217 (133-474)

30 (6-96) 35 (11-58) 251 (116-444)

.002 .69 .26

690 (10-9858)

1408 (143-4996)

.25

3 (0;21)

3 (0;15)

.37

42 (100%)

63 (93%)

.18

41 36 25 16

(98%) (86%) (60%) (38%)

62 56 39 29

(91%) (82%) (57%) (43%)

.35 .84 .98 .79

I: 3 II: 15 III: 24 IV: 0

(7%) (36%) (57%) (0%)

I: 6 II: 22 III: 32 IV: 8

(9%) (32%) (47%) (12%)

.51

Age (y) Gender (m : f) BMI (kg/m2) Duration from biopsy to interferon therapy (months) Follow-up period (months) EF at time of biopsy (%) Left ventricular end-diastolic volume; EDV (mL) NT-proBNP (pg/mL) Myocardial inflammation Myocardial CD2/mm2 Conventional heart failure therapy ACE inhibitor and/or AT-receptor blocker b receptor blocker Diuretics Aldosterone antagonists Digitalis Clinical data NYHA Class

ECG Sinus rhythm Heart rate (min1) Exercise ECG (W) Blood pressure (mm Hg) Systolic Diastolic Echocardiography LVF (qual.) EDD (mm)

38 (90%) 68 (44-114) 100 (25-200)

53 (79%) 71 (45-140) 100 (25-200)

.27 .22 .54

120 (90-180) 70 (50-100)

120 (80-200) 80 (50-121)

.18 .03

0: 0 (0%) 2: 24 (35%) 1: 6 (9%) 3: 36 (53%) 65 (47-80)

.10

0: 2 (5%) 2: 19 (45%) 1: 5 (12%) 3: 16 (38%) 61 (43-83)

.06

IFN, interferon; BMI, body mass index; EF, ejection fraction; EDV, end-diastolic volume; ACE, angiotensin-converting enzyme; NYHA, New York Heart Association; ECG, electrocardiogram; LVF, left ventricular function; EDD, end-diastolic diameter. EF and EDV were determined by left ventriculography during cardiac catheterization or cardiac magnetic resonance imaging. Quantitative parameters: median (range); qualitative parameters: absolute numbers. LVF was assessed qualitatively and classified as either normal (0), mildly (1), moderately (2), or severely (3) depressed. To each class a rank was applied (0-3). Myocardial inflammation was considered with more than 7 CD2 positive lymphocytes/ mm2. t-test was calculated for age, BMI, EF, EDV, EDD; chi-square test was calculated for gender and heart failure medication; Mann-Whitney rank sum test was calculated for follow-up period, NT-proBNP, adverse events, CD2 count, NYHA class, sinus rhythm, heart rate, exercise ECG, blood pressure, and echocardiographic LVF. P values shown in bold were considered to be statistically significant. The significant difference for the follow-up period can be explained by the recruitment of the study population (see Methods section).

given by a university ethics review board and the investigation conforms to the principles outlined in the Declaration of Helsinki. Demographic Data and Clinical Parameters All patients underwent careful medical history and physical examination. Demographic and clinical data such as New York Heart Association (NYHA) class, echocardiographic parameters, drug therapy, 12-lead ECG, ejection fraction measured by cardiac catheterization or magnetic resonance imaging were completed retrospectively by chart review, and medical records as described previously.29 Echocardiography Left ventricular function (LVF) was assessed qualitatively in the apical view and classified as either normal (0), mildly (1), moderately (2), or severely (3) depressed. To each class a rank was applied (0-3). Left ventricular end-diastolic diameter (EDD, mm) was obtained from the parasternal view using M-mode. The individual who performed echocardiography was not involved in the treatment of the patients nor informed about their therapy.

Myocardial Biopsy In patients suffering from dilated cardiomyopathy for at least 3 months, without any improvement of clinical conditions or LVF on regular medical treatment, 7 right ventricular, septal endomyocardial biopsies were obtained. This procedure was in accordance with the recently published recommendations of the European and American cardiac societies.5 Biopsies were processed as previously described and classified by histopathological analysis, immunohistochemistry and presence of viral DNA/RNA.29 Active myocarditis was excluded according to the Dallas criteria.13 A duration of unexplained heart failure for more than 3 months and myocardial detection of viral genome was considered as chronic viral DCM.30 For ethical reasons, we were not able to obtain a second biopsy during the follow-up to reevaluate myocardial infection and inflammation. Specific Diagnosis of Inflammatory and Viral DCM Using immunohistochemical staining for lymphocytes (CD2), the level of myocardial inflammation was evaluated. The secondary diagnosis of inflammation was made if biopsies showed more than 7 leucocytes/mm2.31 The CD2 count was expected to

Interferon b-1b in Viral Cardiomyopathy Table 3. Adverse Events during Interferon b-1b Therapy Adverse Events Control group (n 5 68) Interferon b-1b group (n 5 42): Flulike symptoms Headache Myalgic pain Arthralgia Fever/elevated temperature Shivering/perspiration Loss of hair Fatigue Sleep disorder Reaction at the injection sites Unbalancing Vomiting Loss of appetite Others Abortion of therapy No adverse events at all

N No events 3 16 19 8 10 1 6 5 6 3 1 2 5 1

(7%) (38%) (45%) (19%) (24%) (2%) (14%) (12%) (14%) (7%) (2%) (5%) (12%) (2%) (arthralgia, myalgia, agitation, itch) 9 (21%)

A patient could complain about more than 1 symptom or adverse event. Thus number of adverse events exceeds the number of patients and the percentage exceeds 100%. Total number of patients 110; INF b-1b group 42 patients; control group 68 patients.

correspond with other inflammatory markers such as human leukocyte antigen I, human leukocyte antigen II, CD54, CD3, and CD68 that were assessed routinely.29 However for this current study, we have focused on viral infection, and the secondary diagnosis of inflammation was made by the CD2 count only. Nested polymerase chain reaction was used to detect viral RNA/ DNA. Primers were purchased from Biomers, Germany. We used the primers: GAPDH sense (TAC ATG GTC GGG GTG TTG AA), antisense (AAG AGA GGC ATC CTC ACC CT); adenovirus sense (ACT ACA A(CT)A TTG GCT ACC AGG), antisense (CAA AAC ATA AAG AAG (GT)GT GGG C), sense nested (AAC TTC CAG CCC ATG AGC (AC)G), antisense nested (CTC AAA AGT CAT GTC (GCT)AG CGC); enterovirus sense (CGG TAC CTT TGT GCG CCT GT), antisense (CAG GCC GCC AAC GCA GCC), sense nested (CCC CGG ACT GAG TAT CAA TA), antisense nested (GGC CGC CAA CGC AGC CAC CG); parvovirus B19 sense (AGC ATG TGG AGT GAG GGG GC), antisense (AAA GCA TCA GGA GCT ATA CTT CC), sense nested (GCC AAC TCT GTA ACT TGT AC), antisense nested (AAA TAT CTC CAT GGG GTT GAG); human herpes virus 6 sense (CAT CGC ATA CGT CTC CCA G), antisense (TCT CTA ACG TGT CCG TGC C), sense nested (CCC ATT GGA ACT GTG GTC T), antisense nested (TAG AGA TAT GCA CTC ACC G). Southern Blot analysis and subsequent genome sequencing was performed to confirm and specify viral subtypes and strains. Measurement of NT-proBNP Since 2005, NT-proBNP levels were measured using the NTproBNP electro-chemiluminescence immunoassay (Modular Analytics E170, Roche Diagnostics, Germany) at baseline visit. According to the manufacturer’s instructions, measured NTproBNP levels were expected to be 10% lower than in vivo levels as EDTA-plasma was used. Follow up Follow-up was organized in our outpatient department. The following parameters were assessed for longitudinal and transversal analysis:



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A, NYHA classification (Class I-IV). B, maximum level during exercise ECG (watt). C, echocardiography: for qualitative assessment of LVF, a rank was applied from normal (0), mildly depressed (1), moderately depressed (2), to severely depressed (3). For left ventricular EDD, absolute values were measured. Patients with less than a 6 months follow-up period were not included. Conventional Heart Failure Therapy After diagnosis of DCM, patients received conventional heart failure therapy as recommended by the American College of Cardiology/American Heart Association guidelines for at least 3 months.4 If no adequate improvement of left ventricular function or clinical symptoms was observed, a myocardial biopsy was taken. Analysis of myocardial biopsy took on average about 3 to 4 weeks. Afterwards the results were discussed with the patient and interferon b-1b was requested from their health insurance companies. Finally, patients were invited to start application of interferon b-1b inpatient. In most patients, the overall time from myocardial biopsy to the start of interferon b-1b therapy was 3 months (Table 2). In some patients, a chronic course of DCM was already diagnosed by the referring general practitioner and heart failure medication was started. Thus we could take a biopsy shortly after the first contact in our department. In other patients, we had a longer correspondence with the health insurance companies and thus start of interferon b-1b therapy was delayed. Finally, specific therapy of viral DCM was started within 2 to 7 months after myocardial biopsy (Table 2). Specific Therapy of Viral DCM with Interferon b-1b Off-label therapy with interferon b-1b (Betaferon, Bayer Schering Pharma AG, Germany) was considered for patients showing either no improvement or worsening of clinical symptoms, NYHA class or LVF after 3 months of heart failure therapy. The first week of interferon therapy was initiated inpatient. The dose of interferon b-1b was increased stepwise to reduce side effects. 2  106 units of interferon b-1b were applied subcutaneously 3 times per week, every other day during the first week. During the second week 4  106 units were applied. From week 3 to 24, patients received the maintenance dose of 8  106 units. For each patient with chronic viral DCM reimbursement of costs for specific therapy with interferon b-1b was requested at their health insurance companies. Patients whose health insurance companies did not reimburse the costs for interferon b-1b were referred to the control group (n 5 68). In Germany, there are hundreds of different health insurance companies working independently from each other. This fact attenuates the bias as patients usually belong to different health insurance companies with different refund policies. One major reason for rejection of reimbursement of the costs for interferon b-1b therapy was the poor data on its effectiveness and the lack of significant studies. Within recent years, we could see a decrease in the absorption of costs. The increasing shortness of money in the health sector might additionally contribute to this development. In our opinion socioeconomic factors and race did not influence the refund policies of the health insurance companies.

352 Journal of Cardiac Failure Vol. 16 No. 4 April 2010 Table 4. Comparison of Clinical Data after 6 Months of Follow-up within the Interferon b-1b and Control Group, Respectively

LVF (qual.)

P N EDD (mm) P n NYHA

P n Exercise ECG (W) P n

IFN b-1b Group (n 5 42)

Control Group (n 5 68)

0: 2 (5%) / 0: 7 (17%) 1: 5 (12%) / 1: 12 (29%) 2: 19 (45%) / 2: 13 (31%) 3: 16 (38%) / 3: 10 (24%) !.001 42 / 42 61 / 60 .068 41 / 38 0: 0 (0%) / 0: 5 (12%) I: 3 (7%) / I: 11 (26%) II: 15 (36%) / II: 21 (50%) III: 24 (57%) / III: 4 (10%) IV: 0 (0%) / IV: 1 (2%) !.001 42 / 42 100 / 100 .298 40 / 37

0: 0 (0%) / 0: 8 (12%) 1: 6 (9%) / 1: 18 (28%) 2: 24 (36%) / 2: 29 (45%) 3: 36 (55%) / 3: 10 (15%) !.001 66 / 65 65 / 60 !.001 59 / 61 0: 0 (0%) / 0: 0 (0%) I: 6 (9%) / I: 26 (40%) II: 22 (32%) / II: 31 (48%) III: 32 (47%) / III: 8 (12%) IV: 8 (12%) / IV: 0 (0%) !.001 68 / 65 100 / 100 .429 44 / 58

IFN, interferon; NYHA, New York Heart Association; ECG, electrocardiogram; LVF, left ventricular function; EDD, end-diastolic diameter. Evaluation of clinical outcome for interferon b-1b and control group 6 months after baseline visit, respectively (longitudinal analysis). LVF, EDD, NYHA class, and exercise ECG were analyzed. LVF was assessed qualitatively and classified as either normal (0), mildly (1), moderately (2), or severely (3) depressed. EDD and exercise ECG were described by the median. Patients who present with a normal LVF and without any clinical limitations are characterized by NYHA ‘‘0’’. In each column, the first line describes parameters at baseline visit (left side of the arrow) and 6 months later during follow-up (right side of the arrow). The second line describes the statistical P value. The third line describes the number of subjects being analyzed at baseline visit (left side of the arrow) and 6 months follow-up (right side of the arrow). Wilcoxon signed rank test was calculated for exercise ECG, LVF, and NYHA class; paired t-test was calculated for EDD. P values shown in bold were considered to be statistically significant.

Statistical Analysis

Results

Statistical analysis was performed using SigmaStat version 2.0 software. Chi-square test, Mann-Whitney rank sum test, t-test, Wilcoxon signed rank test, and paired t-test were calculated as indicated. Tests were calculated 2-sided. Paired tests were performed for 6 months follow-up within groups (Table 4) and unpaired tests for comparative follow-up between groups (Tables 1, 2, 5). A P ! .05 was considered statistically significant. Due to the relatively small number of patients included in each subgroup statistical analysis should be interpreted with caution.

Characteristics of the Study Population

Between 1999 and 2008, endomyocardial biopsies were taken from 273 patients with suspected DCM. In 135 (49%) patients, viral genome could be detected. Subtype analysis of viral genome is depicted in Table 1. Eleven patients showed simultaneous infection with 2 different types of virus. Ten patients with viral cardiomyopathy were not included in our study because of a specific myocardial

Table 5. Comparison between Interferon b-1b and Control Group throughout the Follow-up Period

LVF (qual.) P n EDD (mm) P n NYHA P n Exercise ECG (W) P n

Initial

6 Months

12 Months

24 Months

36 Months

2 vs. 3 .10 42 vs. 66 61 vs. 65 .06 41 vs. 59 3 vs. 3 .51 42 vs. 68 100 vs. 100 .54 40 vs. 44

2 vs. 2 .97 42 vs. 65 60 vs. 60 .60 38 vs. 61 2 vs. 2 .79 42 vs. 65 100 vs. 100 .87 37 vs. 58

2 vs. 1 .16 30 vs. 53 61 vs. 59 .65 29 vs. 47 2 vs. 2 .84 30 vs. 52 88 vs. 100 .14 28 vs. 46

2 vs. 1 .02 20 vs.34 62 vs. 59 .19 17 vs. 30 2 vs. 2 .18 20 vs. 34 100 vs. 100 .90 12 vs. 31

2 vs. 2 .45 9 vs. 23 67 vs. 63 .17 8 vs. 18 2 vs. 2 .54 9 vs. 23 100 vs. 100 .37 9 vs. 19

IFN, interferon; NYHA, New York Heart Association; ECG, electrocardiogram; LVF, left ventricular function; EDD, end-diastolic diameter. Evaluation of clinical outcome for interferon b-1b vs. control group during follow-up (transversal analysis). LVF, EDD, NYHA class, and exercise ECG were analyzed. All parameters are described by the median. In each field the first line describes parameters (interferon b-1b group left and control group right), the second line describes the statistical P value, and the third line describes the absolute number of subjects for each group. Because of patient dropout during the follow-up, statistical analysis would not be reasonable beyond 36 months. Although single patients can provide a follow-up to 96 months, we restricted Table 5 to a 36-month period. Mann-Whitney rank sum test was calculated for exercise ECG (initial, 6, 12, and 24 months), EDD (24 months), LVF, and NYHA class; t-test was calculated for exercise ECG (36 months) and EDD (initial, 6, 12, and 36 months). P values shown in bold were considered to be statistically significant.

Interferon b-1b in Viral Cardiomyopathy

affection (Table 1). A total of 42 patients received specific therapy with interferon b-1b and 68 patients with viral cardiomyopathy served as a control. The median follow-up period was 12 (6 to 96) months for the interferon b-1b group and 30 (6 to 96) months for the control group (P 5 .002). No significant differences could be detected for ejection fraction, specific myocardial diagnosis, conventional heart failure therapy, and NT-proBNP plasma level between interferon b-1b and control group at baseline visit (Table 2). The median NT-proBNP level for the interferon b-1b group was 690 (10 to 9858) and for the control group 1408 (143 to 4996). Table 2 depicts the clinical and demographic data for our study population at the time of the first dose of interferon b-1b therapy or myocardial biopsy. Between the interferon b-1b and control group, no significant differences could be analyzed for different ECG parameters, exercise ECG, NYHA class, systolic blood pressure, and echocardiography. All patients included in this study were in a cardiopulmonary stable condition. Individuals with a history of recent cardiopulmonary decompensation did not undergo myocardial biopsy nor received specific therapy. Statistical analysis for clinical outcome (Tables 4, 5) is not affected when the 8 patients from the control group presenting with NYHA Class IV were omitted (data not shown). In Table 2, subjective assessment of the physician performing echocardiography classified 2 patients as ‘‘normal LVF’’ (ie, rank ‘‘0’’), whereas assessment of these 2 patients by cardiac magnetic resonance imaging or levocardiography/ cardiac catheterization resulted in a left ventricular ejection fraction of 57% and 56%, respectively. This might cause a marginal discrepancy in absolute numbers, although without clinical relevance. By far, PVB19 was the most prevalent virus type, and is followed by enterovirus. Simultaneous infection with two different types of virus was detected in 4 patients in the interferon b-1b group and in 7 patients in the control group. No significant differences in virus distribution were detected between both groups. In 22 (20%) patients myocardial inflammation could be observed simultaneously. Inflammatory cardiomyopathy was defined by a myocardial lymphocyte (ie, CD2) count above 7 cells/mm2 using immunohistochemistry. Adverse Events

In 33 (79%) patients with interferon b-1b treatment minor adverse reactions occurred. Most commonly injection site disorders and influenza-like symptoms (eg, headache, fatigue, fever, myalgia, arthralgia) were reported. In the control group, no adverse events were reported and thus they were significantly higher in the interferon b-1b group (P ! .001). No serious adverse events of interferon b-1b therapy could be observed (eg, admission to hospital, death) (Table 3). Adverse events could be reduced by a stepwise increase of the interferon b-1b dose. Usually a maximum of adverse events was reported when the maintenance dose of 8  106 IU interferon b-1b was approached after



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approximately 3 to 4 weeks. Use of nonsteroidal anti-inflammatory drugs (eg, paracetamol, ibuprofen) could effectively lower adverse events. In 9 (21%) patients, no adverse events could be detected at all during the 24 weeks of specific therapy. Only 1 patient aborted interferon b-1b therapy because of adverse events (Table 3). Longitudinal Follow-up

Table 4 shows the 6-month follow-up results for LVF, EDD, NYHA, and exercise ECG within the interferon b-1b and control group, respectively. All patients received standard heart failure therapy,4 but 42 patients were additionally treated with interferon b-1b. After 6 months, a significant improvement of left ventricular global function, EDD (control group), and NYHA class could be observed for both groups. No significant changes were evident for end-diastolic diameter (interferon b-1b group) and exercise ECG, respectively. Due to dropout, the reported number of patients decreased after 6 months follow-up. For exercise ECG no significant changes between baseline visit and 6 months follow-up were detectable. One explanation is the fact that at baseline visit patients showed a significantly worse LVF and NYHA class compared with the 6-month follow-up. Thus, several patients could not perform an exercise ECG for physical reasons at baseline visit. Consequently, the number of patients with exercise ECG is initially smaller. Six months later, consistent application of heart failure therapy improved physical conditions of the study group. Transversal Follow-up

Comparative follow-up was evaluated for interferon b-1b group versus control group (Table 5). At different times LVF, EDD, NYHA, and exercise ECG were compared between both groups during a follow-up period of up to 36 months. In our study population, we were not able to detect a significant benefit of interferon b-1b treatment for clinical outcome during follow-up. Due to dropout of patients during the follow-up, statistical analysis would not be reasonable beyond 36 months. Although single patients could provide a follow-up period to 96 months, we restricted Table 5 to a 36-month period. The relatively large number of dropouts can be explained by the structure of our DCM clinic. Patients were referred to our clinic for special consultation related to myocardial biopsy and interferon b-1b therapy from a large catchment area, but not for longterm treatment or takeover of therapy. Consequently, patients went back to their local attending physicians because of familiarity and convenience, if we were not able to detect a treatable reason or after finishing interferon b-1b therapy. Discussion In 49% of patients suffering from DCM, viral DNA/RNA could be detected within the myocardium. A total of 110 patients with chronic viral DCM were retrospectively

354 Journal of Cardiac Failure Vol. 16 No. 4 April 2010 analyzed for clinical outcome. A total of 42 patients received specific therapy with interferon b-1b and 68 patients served as a control. Both groups were continuously treated with conventional heart failure therapy. Although off-label use with interferon b-1b is feasible and safe under routine clinical practice, we were not able to confirm beneficial effects on left ventricular function and NYHA class as reported by other groups.27,28 Establishing sensitive molecular biological techniques for differential biopsy analysis in DCM has yielded to a tremendous gain of knowledge. The significance of these findings is still a matter of debate and a final consensus has yet to be reached. The pathomechanistic role of viral infection for DCM and consecutive heart failure seems to be apparent but not yet definitely approved.17,19,27 Nevertheless, some reports do not find a correlation of myocardial infection with outcome and could even demonstrate presence of viral genome in healthy hearts.32e34 Detection of different genotypes of the same virusdwhereas only single genomic subgroups are correlated with severe myocardial damage and poor outcomedcould provide an explanation for these findings.20 In our study, all myocardial biopsies were performed under a clinical aspect and all patients presented with myocardial alterations and a reduced left ventricular ejection fraction. In this context, we attributed the detection of viral DNA/RNA to a pathomechanistical role in DCM that represents the background for interferon b-1b therapy. This is described by the terms detection of viral genome and viral cardiomyopathy. Recently, interferon b-1b turned out to be a promising approach for specific treatment in chronic viral DCM. A phase I study reported complete virus elimination and improvement of LVF after 24 weeks of interferon b-1b therapy.27 This study formed the basis for a randomized, placebo-controlled, double-blinded, multicenter phase II study (BICC trial) performed between 2002 and 2005.28 Whereas the phase I study concentrated on patients with myocardial entero- and adenovirus, the BICC trial allowed inclusion of PVB19 and HHV6 later in 2003. Although, added to the inclusion criteria later, the BICC trial reported more than 80% of patients being positive for parvovirus B19. The virus elimination rates were significantly higher in the interferon b-1b group compared with placebo (P 5 .048). At the same time a complete clearance was shown for enterovirus, but only partial parvoviral clearance occurred.28 When applying 8  106 units of interferon b-1b, overall response rates were 50% in the adeno-/enterovirus stratum and 36% in the parvovirus stratum.28 The lower response of parvovirus to interferon b-1b is in line with literature reports.35 There are speculations that potentially higher doses of interferon could improve myocardial parvovirus elimination or LVF.35,36 Different distribution, action and genotypes of parvovirus B19 within the myocardium compared with classical cardiotropic viruses may be a possible explanation for this phenomenon.21,22,37e39 Parvovirus is frequently associated with endothelial and diastolic dysfunction21,22,38 and patients often present

with a spontaneous clinical recovery, whereas, in contrast, HHV6 infection was often presumed to progress into chronic heart failure.39 Thus a major focus of interferon b-1b therapy in chronic viral DCM is the cryptic role of parvovirus infection. Furthermore changing prevalence of viral strains isolated in the myocardium could complicate potential specific treatment modalities because diverse viruses may respond to interferon b-1b differently. Consequently results of clinical trials, although true in the decade when they were published, may be less relevant when the prevalence of myocardial viruses changes. Some groups describe alternative attempts for a specific treatment of chronic DCM like antiphlogistic treatment, immunosuppression, immunoadsorption, and immunoglobulin treatment.25,36 Although at first promising data have been reported for each approach, definite evidence for the effectiveness of these approaches is still missing. Most data are derived from in vitro experiments, registries or phase I studies and robust prospective trials are not yet available. As chronic DCM is a rare disease and not all patients are referred to myocardial biopsy, there is only limited data for specific treatment in chronic viral DCM. The Role of Endomyocardial Biopsy in the Management of Cardiovascular Disease has been published as a scientific statement by the American and European cardiac societies in 2007,5 but for most recommendations there is little evidence. Up to now we do not have obliging guidelines for differential diagnosis and therapy of DCM as we use to have them for many other diseases. The primary aim of our study focused on safety and feasibility of a specific therapy with interferon b-1b in patients suffering from chronic viral DCM under routine clinical practice. Furthermore clinical end points were evaluated under interferon b-1b therapy in a 36 months follow-up (Table 5). In contrast, the BICC trial concentrated on presence and elimination of viral genome in DCM up to 36 weeks after start of specific therapy. Nevertheless clinical symptoms represented secondary variables for the BICC trial. No significant differences are reported for single clinical symptoms, LVF at rest and on exertion, EDD, ESD, inflammatory state, peripheral blood analysis for disease markers, and 6-minute walking test. After 24 weeks of treatment a significant benefit of interferon therapy could be reported for quality of life (Minnesota total score, P 5 .032). A temporary improvement for NYHA class under specific treatment at week 12 was reported (P 5 .013), whereas this benefit disappeared at week 24 (P 5 .073).28 In our study, it seems, numerically speaking, that the control group faired better than the interferon b-1b group. Numerically, LVF and EDD improved more in the control than in the interferon b-1b group after 6 months of follow-up. This difference reached partly statistical significance (Table 4). Also, during the follow-up at 24 months the control group presented with a statistically significant better LVF than the interferon b-1b group (Table 5). Besides statistical reasons, this observation may be a function of a longer follow-up period and greater opportunity

Interferon b-1b in Viral Cardiomyopathy

for medical management in the control group. This is based on an additional amount of patients who were preferentially included in the control group from before 2004. In sum, we were not able to attribute a definitely better outcome to a specific therapy with interferon b-1b. Limitations of our study are in the retrospective design, the relatively small number of patients included in the long-term follow-up and the bias of randomization. Whether a patient was referred to the treatment or control group was solely dependent on the decision of their health insurance companies. This fact represents a major source of bias as there were likely both medical and non-medical variables that could not be corrected for (ie, socioeconomic reasons). Despite these limitations this is the first study applying interferon b-1b therapy under routine clinical practice with a follow-up of 36 months and a focus on clinical outcome. Today, the impact of interferon b-1b for specific antiviral therapy cannot be evaluated definitely, but consideration of viral species, genotype, and drug dose may further clarify its role in a disease with a poor prognosis and limited therapeutic options. Finally, specific treatment with interferon b-1b in chronic viral DCM still represents a worthwhile attempt to improve heart function causally and is related with tolerable adverse events. A sufficiently powered phase III study is required with a focus on clinical outcome and future studies must consider higher doses of interferon b-1b and the contribution of parvovirus B19. Acknowledgments We gratefully acknowledge the staff of our catheterization laboratory for excellent technical support. We thank Anne Wiblin for critical reading of the manuscript.

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