Viral Infections Randomized Clinical Trial of Ganciclovir Vs Acyclovir for Prevention of Cytomegalovirus Antigenemia After Allogeneic Transplantation

Bone Marrow Transplantation (2002) 30, 945–951  2002 Nature Publishing Group All rights reserved 0268–3369/02 $25.00 www.nature.com/bmt Viral infections Randomized clinical trial of ganciclovir vs acyclovir for prevention of cytomegalovirus antigenemia after allogeneic transplantation

LJ Burns, W Miller, C Kandaswamy, TE DeFor, ML MacMillan, J-A van Burik and DJ Weisdorf

Blood and Marrow Transplant Program, University of Minnesota, Minneapolis, MN, USA

Summary: Bone Marrow Transplantation (2002) 30, 945–951. doi:10.1038/sj.bmt.1703770 Cytomegalovirus (CMV) disease remains a major cause Keywords: cytomegalovirus; ganciclovir; acyclovir; ran- of morbidity following allogeneic stem cell transplan- domized clinical trial tation (SCT). In a prospective randomized trial, we tested prophylactic therapy with ganciclovir or acyclo- vir for patients at high risk of disease. Ninety-one CMV seropositive recipients of related (n = 53) and unrelated Cytomegalovirus (CMV) disease is a frequent complication (n = 38) donor transplants were enrolled. All patients following allogeneic stem cell transplantation (SCT).1,2 received intravenous (i.v.) ganciclovir 5 mg/kg every CMV seropositive recipients are at a high risk of CMV h days ؊7to؊2, followed by acyclovir 10 mg/kg i.v. disease, as reactivation of latent endogenous virus is the 12 every 8 h from day ؊1 until neutrophil engraftment. dominant mechanism of infection in immunocompromised Patients were then randomly assigned to either ganciclo- patients.1–5 Despite recent advances in therapy, the mor- vir (n = 45) or acyclovir (n = 46) until day 100 post tality from CMV disease, and particularly CMV pneu- transplant. Any degree of antigenemia was treated with monia, remains quite high. Recent therapeutic strategies ganciclovir 5 mg/kg i.v. twice a day for 2 weeks, fol- have focused on the prevention of CMV disease. lowed by 5 mg/kg i.v. each weekday for 6 weeks. At day Acyclovir and ganciclovir have each been shown to be 100, the cumulative incidence of antigenemia was 31% effective prophylaxis for patients at high risk of CMV dis- (95% CI 17–45%) for ganciclovir and 41% (95% CI ease. Two prospective studies demonstrated a decrease in 26–56%) (P = 0.22) for acyclovir prophylaxis, respect- the occurrence of CMV disease as well as a survival benefit ively. The assigned prophylaxis cohort did not predict of high-dose acyclovir for allogeneic marrow transplant for CMV antigenemia. The cumulative incidence of recipients.5–7 Ganciclovir has been incorporated into vari- CMV disease at 12 months was 13% (95% CI 3–23%) ous prophylactic strategies.8–15 In each of three randomized and 17% (95% CI 6–28%) (P = 0.59) for the studies,8–10 ganciclovir prophylaxis decreased CMV infec- ganciclovir- and acyclovir-treated groups, respectively. tion and/or disease; however, there was no benefit in .An absolute neutrophil count (ANC) р1500 ؋ 106/l at overall survival randomization (P < 0.01) and grade II–IV acute graft- This study was designed to test whether prophylactic versus-host-disease (P = 0.01), but not the assigned ganciclovir is superior to high-dose acyclovir, when gan- prophylaxis cohort (P = 0.62), were independent risk ciclovir is used pre-emptively at first evidence of active factors for CMV disease. The incidence of fungal infec- CMV replication, in a prospective, randomized study. We tions and renal insufficiency was similar across treat- report an analysis of the incidence of CMV antigenemia ment groups; however, bacterial infections and second- measured at 100 days post transplant and CMV disease, in ary neutropenia occurred more frequently in the addition to a comparison of the frequency of complications ganciclovir group. With our study powered to detect a by prophylactic therapy. 60% reduction in antigenemia with ganciclovir prophy- laxis, we did not find a statistically significant difference between ganciclovir and acyclovir when used as part of Materials and methods an overall strategy for prevention of CMV antigenemia and disease in SCT, although fewer side-effects Patients occurred with acyclovir treatment. Ninety-one CMV seropositive recipients of related (n = 53) and unrelated (n = 38) donor SCT were enrolled, irrespec- Correspondence: Dr LJ Burns, University of Minnesota, Mayo Mail Code tive of donor CMV status. All patients were first-time trans- 286, Minneapolis, MN 55455, USA plant recipients. HLA (human leukocyte antigen matching) Received 26 April 2002; accepted 16 September 2002 was determined by A, B serology and DRB high-resolution Ganciclovir vs acyclovir for CMV prophylaxis LJ Burns et al 946 techniques. Data regarding the pre-transplantation charac- CMV surveillance teristics, post-transplantation complications, and survival were collected prospectively by the Biostatistics Support Antigenemia assays were performed weekly from day 0 to Group at the University of Minnesota using standardized day 100 post transplant. The assay was done using a com- methods. Details of CMV therapy and clinical outcomes mercial kit (CMV-Vue: Incstar, Stillwater, MN, USA) were obtained from a review of patients’ medical records. according to the manufacturer’s instructions. Standard methods were used for isolation of CMV from broncho- alveolar lavage fluid and tissue samples, as previously Protocol design described.15 As shown in Figure 1, all patients received intravenous (i.v.) ganciclovir 5 mg/kg every 12 h days Ϫ7toϪ2, fol- CMV therapy lowed by acyclovir 10 mg/kg i.v. every 8 h from day Ϫ1 With any degree of antigenemia (у1 positive cell/50 000 until neutrophil engraftment (absolute neutrophil count leukocytes), prophylaxis was discontinued and patients (ANC) у750 ϫ 106/l for 2 consecutive days). Patients were treated pre-emptively with an induction dose of gan- were then randomly assigned, with stratification for related ciclovir 5 mg/kg i.v. twice daily for 2 weeks, followed by vs unrelated donor transplant, to either acyclovir 800 mg 5 mg/kg i.v. every weekday for 6 weeks. If antigenemia (adults) or 18 mg/kg (children) orally 5 times a day (n = 46) recurred during or after the maintenance phase, induction or ganciclovir 5 mg/kg i.v. every weekday (Monday to with twice daily ganciclovir was restarted and was again Friday) (n = 45) until day 100. All patients received i.v. followed by 6 weeks of maintenance therapy. Foscarnet immunoglobulin (IVIg) 500 mg/kg on days Ϫ6, 0, 7, 21, was given to patients whose antigenemia did not resolve 35, 55, 76 and 98. All patients had CMV serology tested with ganciclovir therapy. All patients in whom CMV dis- within 4 weeks prior to transplantation. Donor CMV serol- ease was diagnosed were treated with the same schedule ogy was tested before blood stem cell or bone marrow har- and duration of ganciclovir, with the addition of IVIg vest. The Institutional Review Board of the University of 500 mg/kg on alternate days for 2 weeks, then twice a week Minnesota approved the trial, and all enrolled patients or for another 4 weeks. If disease recurred during the mainte- their legal guardians gave written informed consent. nance phase, induction was restarted.

Supportive care Definitions Patients who developed an ANC of <750 ϫ 106/l but > CMV antigenemia: one or more positive cells per 50 000 500 ϫ 106/l during prophylactic therapy were treated with (or fewer) leukocytes examined. Recurrent antigenemia granulocyte colony-stimulating factor (G-CSF) at a dose of was defined as any degree of antigenemia occurring follow- 5 ␮g/kg/day and continued receiving the assigned CMV ing complete resolution of antigenemia as a result of pre- prophylaxis. If the ANC fell to <500 ϫ 106/l, prophylaxis emptive ganciclovir therapy; persistent antigenemia was was discontinued until recovery to >750 ϫ 106/l, then defined as failure to resolve CMV antigenemia with pre- restarted with continued G-CSF support. Patients received emptive ganciclovir therapy. CMV disease: signs/symptoms ongoing oral prophylaxis for bacterial infections (penicillin of disease in conjunction with culture of CMV (by conven- V potassium 250 mg twice daily), fungal infections tional or shell-vial technique) from visceral tissue or cer- (fluconazole 200 mg daily), and Pneumocystis carinii pneu- ebrospinal fluid, or pathologic changes of CMV in biopsy monia (trimethoprim-sulfamethoxazole, one double- tissue. CMV pneumonia was defined as interstitial infil- strength tablet twice daily every Monday and Tuesday). trates on chest radiograph accompanied by histologic dem- onstration of CMV in lung biopsy material or a positive CMV culture from bronchoalveolar lavage fluid. CMV gastroenteritis was defined as gastrointestinal symptoms Ganciclovir Acyclovir Ganciclovir 5 mg/kg i.v. accompanied by histologic demonstration of CMV or a 5 mg/kg i.v. 10 mg/kg i.v. Monday–Friday positive CMV culture from biopsy material obtained by every 12 h every 8 h n = 45 endoscopy. Early CMV disease was defined as disease occurring prior to day 100 post transplant; late CMV dis- Acyclovir 800 mg or ease as disease occurring after day 100. CMV related death: 18 mg/kg orally 5 times a day death occurring within 6 weeks of the diagnosis of CMV n = 46 disease in which CMV disease was clinically felt to be a contributing cause.

Day –7 –2/–1 ANC 750 ´106/l +100 Statistical analysis Figure 1 Clinical protocol schema. Patients received intravenous (i.v.) ganciclovir 5 mg/kg every 12 h days Ϫ7toϪ2, followed by acyclovir Prestudy sample size and power projections: The study 10 mg/kg i.v. every 8 h from day Ϫ1 until absolute neutrophil count was designed as a prospective randomized trial. The pri- (ANC) у750 ϫ 106/l for 2 consecutive days. Patients were then randomly assigned, with stratification for type of transplant, to either ganciclovir mary endpoint of the study was the incidence of CMV anti- 5 mg/kg i.v. Monday to Friday (n = 45) or acyclovir 800 mg (adults) or genemia at day 100. To detect a 60% reduction in antigene- 18 mg/kg (children) orally five times a day (n = 46) until day +100. mia with ganciclovir prophylaxis (assuming a 50%

Bone Marrow Transplantation Ganciclovir vs acyclovir for CMV prophylaxis LJ Burns et al 947 incidence in the acyclovir arm) with 80% power at ␣ of Table 1 Patient Characteristics 0.05, a sample size of 90 patients (half randomized to each arm) was needed. The assumed incidence in the acyclovir Characteristics Acyclovir Ganciclovir P arm was based on our own institutional experience and the (n = 46) (n = 45) incidences of CMV infection reported in previously pub- frequency frequency lished studies of acyclovir prophylaxis,5–7 recognizing the Age 0.30 differences in study design, patient population, method of Median (range) 34 (1.5–55) 40 (1.1–55) CMV detection, and statistical analysis of outcomes. Gender 0.25 Secondary endpoints included CMV disease, survival and Male 30 (65%) 24 (53%) complications related to prophylactic therapy. Female 16 (35%) 21 (47%) Diagnosis 0.70 Acute leukemia + MDS 17 (37%) 19 (42%) Antigenemia and disease: the cumulative incidence of CML 12 (26%) 13 (29%) antigenemia and disease were calculated by treating deaths Other malignancy 7 (16%) 5 (11%) from other causes as competing risks.16 Univariate compari- Nonmalignant disease 10 (22%) 8 (18%) Ͼ sons of the impact of study variables on antigenemia and Type of transplant 0.80 Related donor 27 (59%) 26 (58%) disease were determined by the Mantel–Cox log-rank test. URD:matched 11 (24%) 11 (42%) Study variables included age, diagnosis, donor CMV seros- URD:mismatched 8 (17%) 8 (18%) tatus, type of transplant (related vs unrelated matched donor Days from transplant to Ͼ0.80 vs unrelated mismatched donor), days from transplant to randomization Median (range) 22 (13–66) 23 (11–42) randomization, graft-versus-host disease (GVHD) prophy- Donor CMV serostatus 0.60 laxis (methotrexate/cyclosporine vs T cell depletion by Negative 26 (57%) 24 (53%) elutriation), grade II–IV acute GVHD, as well as hemoglo- Positive 20 (44%) 21 (47%) bin (>10 vs р10 g/dl), white blood cell (WBC) (>2500 ver- Stem cell source 0.67 sus р2500 ϫ 106/l), ANC (>1500 vs р1500 ϫ 106/l) and Bone marrow 31 (67%) 34 (76%) у Peripheral blood 14 (30%) 10 (22%) creatinine (<1.5 vs 1.5 mg/dl) at time of randomization. Cord blood 1 (2%) 1 (2%) The independent effect of study variables was analyzed Conditioning regimen >0.80 using Cox proportional hazards regression models. All fac- TBI containing 42 (93%) 42 (96%) tors were tested for the proportional hazards assumption. Bu/Cy 3 (7%) 1 (2%) TLI/Cy 1 (2%) 1 (2%) Acute GVHD was treated as a time-dependent variable in GVHD prophylaxis 0.63 17 these models. MTX/CsA 30 (65%) 28 (62%) T cell depletion by elutriation 13 (28%) 14 (31%) Survival: Patient survival was determined using the Other 3 (7%) 3 (7%) Kaplan–Meier method18 with 95% confidence intervals derived from standard errors. Patients were censored at the MDS = myelodysplastic syndrome; CML = chronic myelogenous leuke- mia; URD = unrelated donor; Bu = busulfan; Cy = cyclophosphamide; date of last contact. Comparison of survival between the TBI = total body irradiation; TLI = total lymphoid irradiation; GVHD = two treatment groups was carried out using Kaplan–Meier graft-versus-host disease; MTX = methotrexate; CsA = cyclosporine. plots and log-rank tests.18

Complications of prophylactic therapy istics were similar between treatment groups, including CMV serology and time from transplant to randomization. Complications studied included secondary neutropenia Ͻ ϫ 6 (defined as ANC 750 10 /l following initiation of CMV antigenemia prophylactic therapy), renal insufficiency (defined as creati- nine у15 mg/dl for patients with a creatinine <1.5 mg/dl Thirty-three (36%) of the 91 patients developed CMV anti- at randomization, or as у3 mg/dl for patients with creatin- genemia before day 100 post-transplant (Table 2). The ine of 1.5–3 mg/dl at randomization), and infections. The cumulative incidence of CMV antigenemia was 31% (95% cumulative incidence of complications was calculated by CI 17–45) with ganciclovir prophylaxis compared with a treating deaths from other causes as competing risks.16 To 41% incidence (95% CI 26–56) with high-dose acyclovir. account for multiple events, incidence density was used to The median number of days to antigenemia was similar by describe the total rate of infections. Incidence density was treatment, as was the median level of antigenemia. We defined as the total number of infections per 1000 patient- further evaluated the effect of treatment group within strata days. Confidence intervals for these rates were determined of various pre-treatment study variables and did not find a by assuming a Poisson distribution for the number of infec- differing risk of antigenemia, except for an increased risk tions. A corresponding P-value was calculated from the in patients у18 years of age who received acyclovir Mantel–Haenzsel chi-square test for person-years data.19 prophylaxis. At day 100, 14 of 29 (48%, 95% CI 33–63%) acyclovir-treated patients у18 years of age compared with eight of 30 (27%, 95% CI 13–41%) (P = 0.04) ganciclovir- Results treated patients developed antigenemia. Multiple regression analysis did not identify any independent risk factors for Table 1 summarizes the demographic characteristics of the antigenemia or show any confounding of the effect of 91 patients by prophylactic treatment. Patient character- prophylactic treatment.

Bone Marrow Transplantation Ganciclovir vs acyclovir for CMV prophylaxis LJ Burns et al 948 Table 2 CMV antigenemia before day 100 post transplantation Table 4 Factors associated with CMV disease

Acyclovir Ganciclovir P Factor Relative risk P (n = 46) (n = 45) (95% CI)

Antigenemia Randomized treatment n (% (95% CI)) 19 (41 (26–56)) 14 (31 (17–45)) 0.22 Acyclovir 1.0 0.39 Days to onset Ganciclovir 0.6 (0.2–1.8) Median (range) 20 (0–90) 36 (0–98) 0.23 ANC at randomization Antigen level (cells/50 000) >1500 ϫ 106/l 1.0 <0.01 Median (range) 2 (1–130) 4 (1–53) 0.22 р1500 ϫ 106/l 13.2 (3.1–55.7) Recurrent or persistent Grade II–IV acute GVHD Antigenemia 8 (17 (6–28)) 3 (7 (0–14)) 0.12 No 1.0 0.01 n (% (95% CI)) Yes 7.4 (1.6–35.5) Type of transplant Related 1.0 URD:match 0.6 0.53 The incidence of recurrent or persistent antigenemia URD:mismatch 3.1 0.08 requiring a second course of therapy with ganciclovir = = and/or foscarnet was similar between groups, although ANC absolute neutrophil count; GVHD graft-versus-host-disease; URD = unrelated donor. there was a trend towards a higher incidence in the acyclo- Shown are the results of multivariate regression models assessing the inde- vir treated group. Eight of 46 (17%) patients who received pendent association of risk factors with CMV disease. GVHD was ana- acyclovir prophylaxis developed recurrent or persistent lyzed as a time-dependent variable. There was no significant interaction CMV antigenemia; three of 45 (7%) patients who received with randomized treatment assignment and any variables examined. ganciclovir prophylaxis required additional therapy (P = 0.12) (Table 2). and ANC (P < 0.01) at time of randomization were the most important factors associated with CMV disease. Mul- CMV disease tiple regression analysis identified ANC р1500 ϫ 106/l at time of randomization (P < 0.01), grade II–IV acute GVHD Of the 91 patients, 14 developed CMV disease with a P = cumulative incidence of 14% (95% CI 7–21%) at 1 year. Of ( 0.01), and a trend towards unrelated mismatched donor (0.08), but not the assigned prophylaxis cohort (P = 0.62), these 14 patients, eight received acyclovir and six received ganciclovir prophylaxis. As shown in Table 3, there was no as independent risk factors for CMV disease (Table 4). difference in the incidence of early or late CMV disease by treatment. In addition, there was no difference in the Toxicity median time to development of disease (for acyclovir, 2.7 months; ganciclovir 3.1 months). Sites of disease were Table 5 demonstrates the toxicity associated with each regi- men. The incidence density of bacterial infections, but not similar between the two groups. Of the eight patients who received acyclovir prophylaxis and developed recurrent or fungal, was greater in the ganciclovir-treated group (12.4 vs persistent antigenemia, six (75%) ultimately developed per 1000 patient-days 8.0 per 1000 patient-days; P = 0.05). Secondary neutropenia developed in 18 of 46 CMV disease. Each of the three patients who received gan- vs ciclovir prophylaxis and developed recurrent or persistent patients (39%) who received acyclovir prophylaxis, 32 of 45 (71%) who received ganciclovir (P = 0.03). Of the antigenemia developed CMV disease. 18 acyclovir-treated patients who developed neutropenia, Univariate comparisons of the impact of study variables on CMV disease demonstrated that lower WBC (P < 0.01) only seven (39%) did so while receiving acyclovir. The remaining patients developed neutropenia after identifi- cation of antigenemia or CMV disease that necessitated Table 3 Cumulative incidence of CMV disease

Occurrence post transplant Acyclovir Ganciclovir P Table 5 Toxicities of prophylactic treatment (n = 46) (n = 45) Toxicity Acyclovir Ganciclovir P n % (95% n % (95% (n = 46) (n = 45) CI) CI) Infections Study entry to day 100 5 11 (3–19) 3 7 (0–14) 0.47 Bacterial 8.0 (5.6–11.2)a 12.4 (9.2–16.3)a 0.05 Gastroenteritis 2 2 Fungal 2.4 (1.1–4.3)a 16 (0.4–2.8)a 0.21 Pneumonia 3 2a Secondary neutropeniab 39 (25–53)d 62 (48–76)d 0.03 Day 101 to one year 3 3 Renal insufficiencyc 33 (19–57)d 38 (24–52)d 0.61 Gastroenteritis 0 1 Pneumonia 3 2 aRate/1000 patient days is shown. Total at 1 year 8 17 (6–28) 6 13 (3–23) 0.59 bNeutropenia defined as ANC <750 ϫ 106/l. cRenal insufficiency defined as creatinine у1.5 mg/dl for patients with a Cumulative incidence (%) and 95% confidence intervals (CI) are shown. creatinine <1.5 mg/dl at randomization, or as у3 mg/dl for patients with P values represent log rank comparisons. creatinine of 1.5–3 mg/dl at randomization. aOne patient had both gastroenteritis and pneumonia. dCumulative incidence (%) and 95% confidence intervals (CI) are shown.

Bone Marrow Transplantation Ganciclovir vs acyclovir for CMV prophylaxis LJ Burns et al 949 ganciclovir therapy. Of the patients randomized to gan- Discussion ciclovir prophylaxis who developed secondary neutropenia, 26 of the 32 (81%) developed secondary neutropenia while The first prospective study of antiviral prophylaxis of CMV receiving prophylactic doses of ganciclovir, with the in transplant recipients was with acyclovir, as reported by remainder developing neutropenia after a change to thera- Meyers et al.5 Intravenous acyclovir prophylaxis decreased peutic doses following the identification of CMV antigene- and delayed the risk of both CMV infection and disease, mia or disease. There was no difference in the overall inci- and was associated with significantly improved survival. dence of renal insufficiency between the two regimens. In a second study by Prentice et al,6,7 CMV seropositive recipients or recipients of a seropositive graft were ran- Reasons for removal from assigned prophylaxis domized to receive one of three acyclovir prophylactic regi- mens differing by route and dose of administration. Intra- The assigned prophylaxis was discontinued and ganciclovir venous acyclovir significantly reduced the risk of CMV therapy instituted for any degree of antigenemia or disease. infection, confirming the results of Meyers et al.5 In One patient assigned to ganciclovir prophylactic therapy addition, the sequential use of i.v. acyclovir followed by was switched to acyclovir when secondary neutropenia was oral acyclovir resulted in a survival advantage of 1 year.5,6 severe and not responsive to interruption of ganciclovir and Over the past decade, ganciclovir has been incorporated growth factor support. An additional patient randomized to into prophylactic and/or pre-emptive treatment strategies ganciclovir was switched to acyclovir when ganciclovir for CMV seropositive patients with demonstrated suc- was temporarily unavailable for use. cess.8,9,11,13 Two prospective, randomized studies showed that ganciclovir was effective in reducing CMV infection Survival and disease when given at time of engraftment to CMV seropositive allogeneic transplant recipients.8,9 Goodrich et There was no statistically significant difference between al8 reported a trial of 64 patients who received high-dose treatment groups in overall survival at 1 year, with 64% i.v. acyclovir until engraftment, at which time patients were (95% CI 50–78%) ganciclovir recipients and 54% (95% CI randomized to ganciclovir or placebo until day 100. By 40–68%) (P = 0.38) acyclovir recipients surviving extending antiviral prophylaxis with ganciclovir, the inci- (Figure 2). Univariate comparisons of the impact of study dence of CMV infection was reduced from 45% to 3%, and variables demonstrated that the type of transplant (related that of disease from 29% in the placebo group to none in vs unrelated donor) was the most important factor associa- the ganciclovir group. Winston et al9 demonstrated that ted with survival (P = 0.05). We next examined factors when ganciclovir was given prior to transplantation, then associated with survival in multiple regression analysis. As restarted at engraftment, the incidence of CMV infection the type of transplant violated the proportional hazards was reduced from 43% in the placebo group to 20% in assumptions, the regression model was stratified for related the ganciclovir-treated group. In an historically controlled vs unrelated donor transplantation. Age у18 was the only study, CMV seropositive patients were given ganciclovir independent risk factor for survival associated with a higher pretransplant from day Ϫ10 to day Ϫ4, followed by high- relative risk of death of 2.2 (95% CI 1.0–4.6) (P = 0.05). dose i.v. acyclovir from 3 days pre-transplant to 29 days Prophylactic treatment with ganciclovir was not an inde- post transplant, then i.v. ganciclovir until day 90.13 The his- pendent significant risk factor for survival with a relative torical control group received i.v. acyclovir alone. The risk of death of 0.8 (95% CI 0.4–1.5) (P = 0.50), and ganciclovir-treated patients had a significantly reduced risk showed no interaction with age or other potentially signifi- of CMV antigenemia, infection and disease. cant variables. There were three CMV-related deaths in the More recently, Boeckh et al10 reported results of a pro- acyclovir group, and one in the ganciclovir-treated group spective, randomized study designed to determine whether (P = 0.32). CMV antigenemia-guided ganciclovir therapy was as effec- tive as ganciclovir administered at engraftment. Compared 1.0 P = 0.38 to antigenemia-guided therapy, ganciclovir at engraftment was associated with more CMV disease occurring after day

0.8 100 and more early invasive fungal infections. These same Ganciclovir investigators performed a retrospective analysis comparing these two groups of randomized patients to a third group 0.6 of patients who had received i.v. acyclovir 500 mg/m2 Acyclovir every 8 h from day 5 before transplant until engraftment 0.4

Probability followed by ganciclovir until day 100. The incidence of CMV disease and CMV-related mortality was similar 0.2 between the groups, leading the authors to conclude that high-dose acyclovir does not improve survival when gan- 20 0.0 ciclovir is given either at engraftment or for antigenemia. 0 1 2 3 4 5 6 7 8 9 10 11 12 As none of these published studies included a direct com- parison of acyclovir to ganciclovir, we designed our study months to determine whether i.v. ganciclovir could reduce the inci- Figure 2 Kaplan–Meier estimates of survival in each of the treatment dence of CMV antigenemia observed with high-dose acy- arms. clovir by 60%. We assumed that 50% of patients would

Bone Marrow Transplantation Ganciclovir vs acyclovir for CMV prophylaxis LJ Burns et al 950 reactivate CMV with high-dose acyclovir prophylaxis. We Secondary neutropenia was a significant toxicity of gan- actually observed a 41% cumulative incidence of CMV ciclovir therapy in our study, confirming reports by other antigenemia with high-dose acyclovir and 31% with gan- investigators.8–10,31 Ganciclovir-induced neutropenia has ciclovir prophylaxis, a 10% absolute difference. This com- been associated with increased rates of bacterial sepsis and pares with a reported 41% and 79% incidence of antigene- invasive fungal infections in marrow transplant recipients, mia in similar patients randomized to receive ganciclovir as well as mortality.8,10,31 Although we observed more fre- prophylaxis and placebo, respectively.10 To detect a 10% quent bacterial infections in the ganciclovir-treated group, difference in the incidence of antigenemia with 70% power the rate of fungal infections was similar, which may in part and a type I error rate of 5% would have required a sample be attributed to our use of prolonged fungal prophylaxis. size of 310 patients, with 155 per treatment arm. The small patient numbers in this study make it very Several aspects of our study may have contributed to the difficult to draw definitive conclusions on the observed dif- observed outcomes, including the incorporation of eight ference of 10% between the two treatments. Prophylactic doses of IVIg to day 98. Immunoglobulin has been shown ganciclovir, administered in conjunction with pre-emptive to modify the severity of CMV infection and prevent inter- therapy for any degree of CMV antigenemia, may reduce stitial pneumonia, and possibly GVHD in allogeneic recipi- the incidence of CMV antigenemia compared to high-dose ents.21 The pre-emptive strategy we used that included both acyclovir. However, a much larger study would be needed treatment of low-grade antigenemia as well as continuing to confirm the absolute difference of 10% we observed. ganciclovir therapy for a minimum of 8 weeks may also Alternatively, our data suggest that high-dose oral acyclo- have contributed to the relatively low incidence of CMV vir, an easily administered, less expensive drug with fewer disease we observed in both treatment arms. Others have side-effects compared to ganciclovir, is efficacious as CMV demonstrated that delaying treatment until high-grade anti- prophylaxis in this setting of pre-emptive therapy with an genemia or discontinuing ganciclovir early after antigene- acceptable low incidence of CMV disease. Valacyclovir, an mia resolves can be detrimental to success.10,22 oral prodrug of acyclovir, has been shown in a prospective, Several factors have been associated with the develop- randomized trail to be more effective than acyclovir in pre- ment of CMV disease after transplantation including CMV venting CMV reactivation with a similar incidence of CMV positive serostatus before transplant, increased age, T cell disease.32 Other antiviral drugs, including foscarnet, cido- depletion, post-transplant immunosuppression, acute fovir and valganciclovir are also being studied for preven- GVHD and its treatment, total body irradiation in con- tion of CMV disease.33–36 As prophylactic and early treat- ditioning regimens, and unrelated or mismatched ment strategies aimed at further reduction of CMV donors.1,2,23–25 The current study confirmed that patients antigenemia and disease are developed and tested, consider- who develop acute GVHD are at increased risk for CMV ation should be given to comparison with high-dose acyclo- disease, and demonstrated also that early neutropenia may vir or valacyclovir in study designs. be a risk factor, perhaps as a hallmark of delayed immune recovery of effective antiviral surveillance. Similar to the 25 results reported by Foot et al, we saw no difference in References CMV disease between allogeneic recipients of related vs unrelated transplants. Although there was a trend towards 1 Meyers JD, Flournoy N, Thomas ED. Risk factors for cytome- an increased risk following unrelated donor mismatch trans- galovirus infection after human marrow transplantation. J plantation, the number of patients receiving such trans- Infect Dis 1986; 153: 478–488. plants was quite small. We earlier reported that T cell- 2 Miller W, Flynn P, McCullough J et al. Cytomegalovirus depleted marrow was associated with an increased risk for infection following bone marrow transplantation: an associ- CMV disease in patients who did not receive anti-viral ation with acute graft versus host disease. Blood 1986; 67: prophylactic therapy.23 In this study, we saw no association 1162–1167. with T cell depletion and either CMV antigenemia or dis- 3 Riddell SR. Pathogenesis of cytomegalovirus pneumonia in ease, confirming a more recent analysis of patients undergo- immunocompromised hosts. Sem Resp Infect 1995; 10: 199– ing transplantation at our center who routinely received 208. 26 4 Zaia JA, Forman SJ. Cytomegalovirus infection in the bone anti-viral prophylaxis. marrow transplant recipient. In: Rubin RH (ed.). Infectious The most common manifestations of CMV disease, Disease Clinics of North America: Infection in transplan- pneumonia and gastroenteritis, typically occur 45 to 60 tation. WB Saunders Co.: Philadelphia and London, 1995, days after transplantation.27 During the past few years, pp 879–900. CMV disease has been increasingly diagnosed late after 5 Meyers JD, Reed EC, Shepp DH et al. Acyclovir for preven- transplantation.10,28,29 It has been suggested that the late tion of cytomegalovirus infection and disease after allogeneic onset of CMV disease may be due to the use of ganciclovir marrow transplantation. New Engl J Med 1988; 318:70–75. prophylaxis, which delays recovery of CMV-specific T cell 6 Prentice HG, Gluckman E, Powles RP et al. The impact of immunity.30 In our study, the incidence of CMV disease long-term acyclovir on cytomegalovirus infection and survival was small in each treatment arm, with similar incidences in allogeneic bone marrow transplantation. Lancet 1994; 343: 749–753. before and after day 100. This finding of no apparent 7 Prentice HG, Gluckman E, Powles RL et al. Long-term sur- increase in incidence of late onset CMV disease may be vival in allogeneic bone marrow transplant recipients follow- secondary to the different schedule of administration of the ing acyclovir prophylaxis for CMV infection. Bone Marrow maintenance ganciclovir – each weekday instead of daily Transplant 1997; 19: 129–133. as in other reported studies.10,28,29 8 Goodrich JM, Bowden RA, Fisher L et al. Ganciclovir

Bone Marrow Transplantation Ganciclovir vs acyclovir for CMV prophylaxis LJ Burns et al 951 prophylaxis to prevent cytomegalovirus disease after allog- monia after bone marrow transplantation. Risk factors and eneic marrow transplant. Ann Intern Med 1993; 118: 173–178. response to therapy. Transplantation 1993; 55: 1339–1346. 9 Winston DJ, Ho WG, Bartoni K et al. Ganciclovir prophylaxis 24 Takenaka K, Gondo H, Tanimoto K et al. Increased incidence of cytomegalovirus infection and disease in allogeneic bone of cytomegalovirus (CMV) infection and CMV-associated dis- marrow transplant recipients: results of a placebo-controlled, ease after allogeneic bone marrow transplantation from unre- double-blind trial. Ann Intern Med 1993; 118: 179–184. lated donors. Bone Marrow Transplant 1997; 19: 241–248. 10 Boeckh M, Gooley TA, Myerson D et al. Cytomegalovirus 25 Foot AB, Pamphilon D, Caul EO, et al. 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