Antiviral Therapy 2015; 20:249–254 (doi: 10.3851/IMP2818)
Case report Management of multidrug-resistant CMV infection in immunocompromised patients: case report of a heart-transplant recipient and review of the literature Claire Deback1, Sonia Burrel2,3, Shaïda Varnous4, Guislaine Carcelain2,5, Françoise Conan3, Zaïna Aït-Arkoub3, Brigitte Autran2,5, Iradj Gandjbakhch4, Henri Agut2,3, David Boutolleau2,3* INSERM UMR S996 and AP-HP, Hôpitaux Universitaires Paris-Sud, Service de Virologie, Villejuif, France Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d’Immunologie et des Maladies Infectieuses (CIMI-Paris), INSERM U1135, Paris, France 3 AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Service de Virologie, Paris, France 4 AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Service de Transplantation Thoracique, Paris, France 5 AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Département d’Immunologie, Paris, France 1 2
*Corresponding author e-mail: [email protected]
Cytomegalovirus (CMV) remains a leading cause of morbidity after solid organ transplantation. The efficiency of antivirals for the treatment of CMV infections may be hampered because of the emergence of CMV resistance to antivirals. The development of CMV multidrug resistance, which remains uncommon but does occur, constitutes a clinically challenging complication and may contribute
to difficult therapeutic management and adverse clinical outcome. We report here the observation of the emergence of a multidrug-resistant CMV infection in a hearttransplant recipient and review the literature on similar cases to identify the potential strategies for the successful management of CMV multidrug resistance among immunocompromised patients.
Introduction Cytomegalovirus (CMV) remains a leading cause of morbidity and mortality after solid organ transplantation (SOT). Only a few antiviral drugs are currently licensed for the systemic treatment of CMV infections: ganciclovir (GCV) and its oral prodrug valganciclovir (VGCV), foscarnet (FOS) and cidofovir (CDV). The emergence of CMV resistance to antivirals among immunocompromised patients constitutes a rising therapeutic challenge [1]. Moreover, given the paucity of antiviral drugs, this phenomenon may have devastating consequences. In the field of SOT, risk factors for the emergence of CMV resistance to antivirals have been identified such as the degree of host immunosuppression, the type of transplantation, the duration of drug exposure, or a SOT performed with an organ from a CMV-seropositive donor in a CMVseronegative recipient (D+/R- status) [2]. The global incidence of drug resistance among D+/R- recipients treated for CMV infection varies from 5% to 10% [1]. The molecular mechanisms of CMV resistance to ©2015 International Medical Press 1359-6535 (print) 2040-2058 (online)
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current antivirals rely on the presence of mutations within viral genes encoding UL97 phosphotransferase and UL54 DNA polymerase. The emergence of multidrug-resistant CMV infection may be observed. This phenomenon may be associated with a single CMV clinical isolate harbouring different mutations located in both UL97 and UL54 genes, or in UL54 gene alone, and conferring resistance to GCV, FOS and CDV. Otherwise, CMV multidrug resistance may result from distinct CMV clinical isolates, each of them harbouring one or two mutations conferring resistance to one or two different antiviral drugs. However, whatever its origin, the therapeutic management of multidrugresistant CMV infection or disease remains challenging and, to date, no consensus recommendations are available in that field. We report here the occurrence of a multidrug-resistant CMV infection in a 55-year-old heart-transplant recipient and discuss the management of this type of clinical situation against the background of the literature. 249
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Discussion
In March 2006, heart transplantation was performed in a 55-year-old man who was diagnosed with ischaemic dilated cardiopathy. This CMV-seronegative recipient was transplanted with a graft from a CMVseropositive donor. He received no anti-CMV prophylaxis. CMV infection was monitored by viral DNA quantitation in whole blood [3] twice a week during the first month post-transplantation, once a week during the second month post-transplantation and then twice a month. The patient developed asymptomatic CMV primary infection, consisting of an isolated CMV viraemia, 3 weeks after the transplantation. He therefore received a treatment with intravenous GCV (10 mg/kg/day) during 3 weeks, followed by a maintenance treatment with oral VGCV (900 mg/day). After an initial decrease, CMV load reincreased 2 months later and peaked over 100,000 copies/ml (Figure 1). At that time, the genotypic resistance testing, performed by conventional sequencing as previously described [4], revealed A594V and L595S changes in UL97 phosphotransferase, as mixed populations, conferring resistance to GCV. The antiviral treatment was then switched to intravenous FOS (90 mg/kg) twice a day during 3 weeks, and then once a day during 7 weeks. When FOS treatment was stopped (8 months post-transplantation) because of renal toxicity, CMV load was still detectable (109 copies/ml) and showed a new elevation with a peak at 35,855 copies/ml 1 month later (Figure 1). At that time, the genotypic resistance testing revealed several resistance mutations: L595S change (UL97) conferring resistance to GCV, P522S and L802M (UL54) associated with cross-resistance to GCV/CDV and GCV/FOS, respectively [1]. It is noteworthy that both the P522S change, elicited by prolonged GCV treatment, and the L802M change, elicited by FOS treatment, were detected about 2 weeks after the respective drugs were discontinued. Because of the CMV multidrug resistance, all antiviral treatments were stopped 10 months posttransplantation, the dose of cyclosporin A (CsA) was reduced and a treatment with everolimus, an inhibitor of mammalian target of rapamycine (mTOR), was initiated. CMV load remained approximately 10,000 copies/ml during 7 weeks and then decreased slowly and remained below 500 copies/ml (Figure 1). The CMV-specific CD8+ T-cell immunity was investigated by means of ELISPOT assays [5]. At 10 months post-transplantation, the results of functional assays were negative whereas they were highly positive at 14 months post-transplantation, indicating CMV-specific cellular immunity recovery. The patient remained free of symptoms during all the different episodes of CMV infection.
Among immunocompromised patients, the efficiency of antiviral drugs used for the treatment of CMV infections may be hampered because of the emergence of CMV resistance to antivirals. Moreover, the development of CMV multidrug-resistant infection, which remains uncommon but does occur, constitutes a clinically challenging complication and may contribute to difficult therapeutic management and adverse clinical outcome. In heart-transplant recipients, the incidence of CMV resistance to GCV was reported to be 1.5% and was significantly associated with CMV D+/R- status [6]. Two cases of CMV resistance to GCV and CDV have been previously reported in Australian patients [7]. To our knowledge, this is the first report describing a multidrug-resistant CMV infection after heart transplantation. The D+/R- heart-transplant recipient presented herein, considered at high-risk of CMV infection, did not receive VGCV prophylaxis. Instead, CMV load was monitored in blood at regular intervals in order to detect early viral replication and start a pre-emptive antiviral treatment. However, according to the international consensus guidelines on the management of CMV in SOT, this patient should have received universal VGCV prophylaxis [2]. Nevertheless, the emergence of CMV resistance has been reported in a high-risk heart transplant recipient despite VGCV prophylaxis [4]. Moreover, for the patient presented herein, the pre-emptive treatment should have been initiated probably earlier, once viral load had reached the threshold of 3 log copies/ml, as previously reported [4]. Different types of management of multidrug-resistant CMV infections have been reported so far in the literature [7–18] (Table 1). All patients presented immunodeficiency disorders: severe combined immunodeficiency (n=1), HIV infection (n=2), haematopoietic stem cell transplantation (n=1) and SOT (n=9). Among SOT recipients, 7/8 were at high-risk for developing CMV resistance to antivirals according to their D+/R- status [11–18]. CMV-associated clinical symptoms were observed in all patients except one [12]. In particular, retinitis occurred among seven of them. The patient presented herein remained free of symptoms despite multidrug-resistant CMV infection. In transplant recipients, CMV load in the initial phase of active infection and the rate of increase in viral load have been reported to correlate with CMV disease [19]. In the present case, the initial CMV load was 3.21 log and the rate of change in CMV load was 0.41 log genomes/ ml/day (Figure 1). According to the contour map provided by the authors, the patient had a risk of approximately 30% to develop CMV disease [19]. Most clinical reports of CMV drug resistance have underlined
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Figure 1. Kinetics of CMV load, anti-CMV and immunosuppressive treatments and emergence of CMV multidrug resistance
MMF
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Cytomegalovirus (CMV) DNA load (circles) measured by real-time PCR in whole blood samples is represented (logarithmic scale) during the post-transplantation period. The horizontal dashed line represents the limit of detection of CMV real-time PCR assay (that is, 25 copies/ml). The detection of the different CMV resistance mutations is indicated above the figure as follows: (+) presence of mutation in 100% of the detected sequence population, (±) presence of mutation as a mixed population and (-) absence of mutation. Durations of immunosuppressive and anti-CMV treatments are indicated by horizontal arrows at the top of the graph. FOS, foscarnet; GCV, ganciclovir; MMF, mycophenolate mofetil; VGCV, valganciclovir. Antiviral Therapy 20.2
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Prophylactic antiviral Curative treatments antiviral treatments
Resistance mutations in pUL97
Resistance mutations in pUL54 (associated Management of drug resistance) multidrug resistance Outcome
[11]
[17]
[13]
[7]
[15]
[18]
[16]
[12]
[14]
[10] [18]
[9]
[8]
Reference
a Pneumonitis, encephalitis, retinitis. bSmall intestine, stomach, pancreas, kidney. CDV, cidofovir; CMV-Ig, CMV immune globulin; D/R, donor/recipient CMV serostatus; F, female; FOS, foscarnet; GCV, ganciclovir; HSC, haematopoietic stem cell; IS, immunosuppression; m, month; M, male; NA, not available; SCID, severe combined immonodeficiency; Tx, transplantation; y, year.
3 m, M SCID Multiorgan diseasea None GCV, FOS M460V/I K513N (GCV/CDV) CMV-Ig Death CDV A594V T700A (FOS) L595S 42 y, M HIV infection Retinitis GCV GCV, FOS C603W F412C (GCV/CDV) Association of anti- Death CDV L802M (FOS) CMV approved drugs NA, M HIV infection Retinitis None GCV, FOS L595S Del 981-982 (GCV/CDV/FOS) None Progression of retinitis 47 y, F D-/R+ HSC Tx Fever VGCV GCV C592G L545S (GCV/CDV) Artesunate Favourable Neutropenia FOS, CDV D588N (GCV/CDV/FOS) 43 y, F D+/R- kidney Tx Pneumonitis VGCV GCV, FOS H520Q N408K (GCV/CDV) CMV-Ig Favourable Retinitis Fomivirsen A594V A834P (GCV/CDV/FOS) Leflunomide Colitis D413E (GCV/CDV) V787L (FOS) 68 y, F D+/R- kidney Tx None None VGCV, GCV None A834P (GCV/CDV/FOS) FOS, GCV Transplant rejection CMV-Ig 43 y, F D+/R- kidney Tx Retinitis VGCV VGCV, GCV, NA NA (GCV/CDV/FOS) CMV-Ig Favourable Uveitis FOS Leflunomide 60 y, M D+/R- kidney Tx Fever VGCV, GCV VGCV, GCV, C592G A987G (GCV/CDV) Artesunate Death Hepatic cytolysis FOS N408K (GCV/CDV) Encephalitis G841A (GCV/FOS) 68 y, F D+/R- lung Tx Retinitis VGCV, GCV VGCV, GCV, M460I A834P (GCV/CDV/FOS) Maribavir Favourable Duodenitis FOS, CDV L595S A987G (GCV/CDV) NA Lung Tx Colitis VGCV, GCV VGCV, GCV E596G F412S (GCV/CDV) CMV-Ig NA Duodenitis CDV L802M (FOS) IS reduction Gastritis A809V (GCV/FOS) 39 y, M D+/R+ lung Tx Pneumonitis VGCV GCV, FOS, A594T/V V715M (FOS) CMV-Ig Favourable Retinitis CDV C603W A987G (GCV/CDV) Leflunomide Colitis CMX001 Artesunate Letermovir 57 y, F D+/R- lung Tx Gastrointestinal disease VGCV VGCV, GCV, A594P K513N (GCV/CDV) VGCV, FOS Favourable FOS E756Q (FOS) CMV-Ig Leflunomide 34 y, F D+/R- multiorgan Txb Diarrhoea VGCV VGCV, GCV C603W L545S (GCV/CDV) Leflunomide Favourable Renal impairment FOS, CDV Q578H (FOS) IS reduction
CMV-associated Age, sex Context symptoms
Table 1. Overview of literature on the management of multidrug-resistant CMV infections in immunocompromised patients
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the highly symptomatic presentations [20], and most of multidrug-resistant CMV infections reported so far were associated with severe symptoms (Table 1). Nevertheless, drug resistance mutations have also been observed in relatively asymptomatic subjects [1]. Given those data, the absence of symptoms in the patient presented herein is not that surprising. Before the emergence of multidrug-resistant CMV infection, all patients received first-line (V)GCV followed by second-line FOS treatments and seven patients received third-line CDV treatment (Table 1). The retinitis of one patient was treated with the antisense nucleotide fomivirsen [14]. For each patient, CMV multidrug resistance was associated with resistance mutations located both in UL97 phosphotransferase, conferring GCV resistance, and in UL54 DNA polymerase. Two different genotypic resistance patterns were identified in UL54 DNA polymerase: either one mutation accounting by itself for multidrug resistance, for example, the deletion 981–982 or A834P change, or one mutation conferring cross-resistance to GCV/CDV and one mutation conferring resistance to FOS. Similarly to previous reports, CMV multidrug resistance emerged in the heart-transplant recipient presented here following antiviral treatments with (V)GCV and FOS, but no CDV [10,12,16], and was associated with several mutations located in UL97 phosphotransferase and UL54 DNA polymerase (Table 1). The kinetics of these resistance mutations during the study period in both viral enzymes and the detection of mixtures of wild type and resistant sequences indicate that CMV multidrug resistance is likely due to the infection of the patient by different CMV strains harbouring different resistance mutations (Figure 1). Cloning experiments or new-generation sequencing approaches may help to address this issue of single versus multiple infecting strains. The question of CMV multidrug resistance management in immunocompromised patients is still pending. A variety of strategies exist, but none of them has been evaluated adequately. Since it is well-recognized that patients lacking a specific immune response to CMV are at increased risk for developing CMV disease, one option consists in the improvement of antiviral host defences by the reduction of immunosuppression and the use of adjunctive therapies such as CMV-Ig or adoptive infusion of CMV-specific T-cells [2,20]. The immunomodulatory agents leflunomide and everolimus have been associated with lower CMV incidence [17,21,22]. Another strategy consists the use of experimental antiCMV agents currently under investigation in clinical trials: the CDV prodrug CMX001, the UL97 phosphotransferase inhibitor maribavir, the terminase complex inhibitor letermovir, or the antimalarial drug artesunate [1,2,20,23]. In the present case, the management of CMV multidrug resistance consisted the reduction Antiviral Therapy 20.2
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of CsA dose and the addition of everolimus, but the decrease of CMV load was very low. Indeed the recovery of CMV-specific T-cell immunity 14 months after transplantation is likely to have permitted the improvement of CMV infection. The prevention of the emergence of CMV resistance to antivirals remains highly required in transplant recipients by evaluation of risk factors, surveillance of CMV load, and use of prophylactic/pre-emptive antiviral treatments. Despite its relative infrequency, the management of CMV multidrug resistance has to be improved, in particular with new antivirals lacking cross-resistance with current drugs. In that field, maribavir and letermovir appear to be promising molecules [13,15]. Moreover, salvage therapies consisting in the choice of specific maintenance immunosuppressive drugs with antiviral properties, like leflunomide, may constitute an attractive alternative strategy [17,24,25].
Acknowledgements This work was supported in part by the Association pour la Recherche sur les Infections Virales (ARIV).
Disclosure statement The authors declare no competing interests.
References 1. 2.
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Lurain NS, Chou S. Antiviral drug resistance of human cytomegalovirus. Clin Microbiol Rev 2010; 23:689–712. Kotton CN, Kumar D, Caliendo AM, et al. Updated international consensus guidelines on the management of cytomegalovirus in solid-organ transplantation. Transplantation 2013; 96:333–360. Deback C, Fillet AM, Dhedin N, et al. Monitoring of human cytomegalovirus infection in immunosuppressed patients using real-time PCR on whole blood. J Clin Virol 2007; 40:173–179. Boutolleau D, Deback C, Bressollette-Bodin C, et al. Resistance pattern of cytomegalovirus (CMV) after oral valganciclovir therapy in transplant recipients at high-risk for CMV infection. Antiviral Res 2009; 81:174–179. Sacre K, Nguyen S, Deback C, et al. Expansion of human cytomegalovirus (HCMV) immediate-early 1-specific CD8+ T cells and control of HCMV replication after allogeneic stem cell transplantation. J Virol 2008; 82:10143–10152. Li F, Kenyon KW, Kirby KA, Fishbein DP, Boeckh M, Limaye AP. Incidence and clinical features of ganciclovirresistant cytomegalovirus disease in heart transplant recipients. Clin Infect Dis 2007; 45:439–447. Iwasenko JM, Scott GM, Naing Z, Glanville AR, Rawlinson WD. Diversity of antiviral-resistant human cytomegalovirus in heart and lung transplant recipients. Transpl Infect Dis 2011; 13:145–153. Blackman SC, Lurain NS, Witte DP, Filipovich AH, Groen P, Schleiss MR. Emergence and compartmentalization of fatal multi-drug-resistant cytomegalovirus infection in a patient with autosomal-recessive severe combined immune deficiency. J Pediatr Hematol Oncol 2004; 26:601–605. Chou S, Marousek G, Guentzel S, et al. Evolution of mutations conferring multidrug resistance during prophylaxis and therapy for cytomegalovirus disease. J Infect Dis 1997; 176:786–789. 253
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10. Chou S, Miner RC, Drew WL. A deletion mutation in region V of the cytomegalovirus DNA polymerase sequence confers multidrug resistance. J Infect Dis 2000; 182:1765–1768. 11. Goldsmith PM, Husain MM, Carmichael A, Zhang H, Middleton SJ. Case-report: Multidrug-resistant cytomegalovirus in a modified multivisceral transplant recipient. Transplantation 2012; 93:e30–e32. 12. Hantz S, Garnier-Geoffroy F, Mazeron MC, et al. Drugresistant cytomegalovirus in transplant recipients: a French cohort study. J Antimicrob Chemother 2010; 65:2628–2640. 13. Kaul DR, Stoelben S, Cober E, et al. First report of successful treatment of multidrug-resistant cytomegalovirus disease with the novel anti-CMV compound AIC246. Am J Transplant 2011; 11:1079–1084. 14. Levi ME, Mandava N, Chan LK, Weinberg A, Olson JL. Treatment of multidrug-resistant cytomegalovirus retinitis with systematically administered leflunomide. Transpl Infect Dis 2006; 8:38–43. 15. Strasfeld L, Lee I, Tatarowicz W, Villano S, Chou S. Virologic characterization of multidrug-resistant cytomegalovirus infection in 2 transplant recipients treated with maribavir. J Infect Dis 2010; 202:104–108. 16. Dunn JH, Weinberg A, Chan LK, Mandava N, Levi ME, Olson JL. Long-term suppression of multi-drug-resistant cytomegalovirus retinitis with systemically administered leflunomide. JAMA Ophthalmol 2013; 131:958–960. 17. Verkaik NJ, Hoek RA, van Bergeijik H, et al. Leflunomide as part of the treatment for multi-drug-resistant cytomegalovirus disease after lung transplantation: case report and review of the literature. Transpl Infect Dis 2013; 15:E243–E249. 18. Germi R, Mariette C, Alain S, et al. Success and failure of artesunate treatment in five transplant recipients with disease caused by drug-resistant cytomegalovirus. Antiviral Res 2014; 101:57–61.
19. Emery VC, Sabin CA, Cope AV, Gor D, Hassan-Walker AF, Griffiths PD. Application of viral-load kinetics to identify patients who develop cytomegalovirus disease after transplantation. Lancet 2000; 355:2032–2036. 20. Avery RK. Update in management of ganciclovir-resistant cytomegalovirus infection. Curr Opin Infect Dis 2008; 21:433–437. 21. Avery RK, Mossad SB, Poggio E, et al. Utility of leflunomide in the treatment of complex cytomegalovirus syndromes. Transplantation 2010; 90:419–426. 22. Brennan DC, Legendre C, Patel D, et al. Cytomegalovirus incidence between everolimus versus mycophenolate in de novo renal transplants: pooled analysis of three clinical trials. Am J Transplant 2011; 11:2453–2462. 23. Goldner T, Hewlett G, Ettischer N, Rubsamen-Schaeff H, Zimmermann H, Lischka P. The novel anticytomegalovirus compound AIC246 (Letermovir) inhibits human cytomegalovirus replication through a specific antiviral mechanism that involves the viral terminase. J Virol 2011; 85:10884–10893. 24. Brennan DC, Aguado JM, Potena L, et al. Effect of maintenance immunosuppressive drugs on virus pathobiology: evidence and potential mechanisms. Rev Med Virol 2013; 23:97–125. 25. Sabé N, Gonzalez-Costello J, Rama I, et al. Successful outcome of ganciclovir-resistant cytomegalovirus infection in organ transplant recipients after conversion to mTOR inhibitors. Transpl Int 2012; 25:e78–e82.
Accepted 18 June 2014; published online 25 June 2014
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Case report Management of multidrug-resistant CMV infection in immunocompromised patients: case report of a heart-transplant recipient and review of the literature Claire Deback1, Sonia Burrel2,3, Shaïda Varnous4, Guislaine Carcelain2,5, Françoise Conan3, Zaïna Aït-Arkoub3, Brigitte Autran2,5, Iradj Gandjbakhch4, Henri Agut2,3, David Boutolleau2,3* INSERM UMR S996 and AP-HP, Hôpitaux Universitaires Paris-Sud, Service de Virologie, Villejuif, France Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d’Immunologie et des Maladies Infectieuses (CIMI-Paris), INSERM U1135, Paris, France 3 AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Service de Virologie, Paris, France 4 AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Service de Transplantation Thoracique, Paris, France 5 AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière – Charles Foix, Département d’Immunologie, Paris, France 1 2
*Corresponding author e-mail: [email protected]
Cytomegalovirus (CMV) remains a leading cause of morbidity after solid organ transplantation. The efficiency of antivirals for the treatment of CMV infections may be hampered because of the emergence of CMV resistance to antivirals. The development of CMV multidrug resistance, which remains uncommon but does occur, constitutes a clinically challenging complication and may contribute
to difficult therapeutic management and adverse clinical outcome. We report here the observation of the emergence of a multidrug-resistant CMV infection in a hearttransplant recipient and review the literature on similar cases to identify the potential strategies for the successful management of CMV multidrug resistance among immunocompromised patients.
Introduction Cytomegalovirus (CMV) remains a leading cause of morbidity and mortality after solid organ transplantation (SOT). Only a few antiviral drugs are currently licensed for the systemic treatment of CMV infections: ganciclovir (GCV) and its oral prodrug valganciclovir (VGCV), foscarnet (FOS) and cidofovir (CDV). The emergence of CMV resistance to antivirals among immunocompromised patients constitutes a rising therapeutic challenge [1]. Moreover, given the paucity of antiviral drugs, this phenomenon may have devastating consequences. In the field of SOT, risk factors for the emergence of CMV resistance to antivirals have been identified such as the degree of host immunosuppression, the type of transplantation, the duration of drug exposure, or a SOT performed with an organ from a CMV-seropositive donor in a CMVseronegative recipient (D+/R- status) [2]. The global incidence of drug resistance among D+/R- recipients treated for CMV infection varies from 5% to 10% [1]. The molecular mechanisms of CMV resistance to ©2015 International Medical Press 1359-6535 (print) 2040-2058 (online)
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current antivirals rely on the presence of mutations within viral genes encoding UL97 phosphotransferase and UL54 DNA polymerase. The emergence of multidrug-resistant CMV infection may be observed. This phenomenon may be associated with a single CMV clinical isolate harbouring different mutations located in both UL97 and UL54 genes, or in UL54 gene alone, and conferring resistance to GCV, FOS and CDV. Otherwise, CMV multidrug resistance may result from distinct CMV clinical isolates, each of them harbouring one or two mutations conferring resistance to one or two different antiviral drugs. However, whatever its origin, the therapeutic management of multidrugresistant CMV infection or disease remains challenging and, to date, no consensus recommendations are available in that field. We report here the occurrence of a multidrug-resistant CMV infection in a 55-year-old heart-transplant recipient and discuss the management of this type of clinical situation against the background of the literature. 249
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Case report
Discussion
In March 2006, heart transplantation was performed in a 55-year-old man who was diagnosed with ischaemic dilated cardiopathy. This CMV-seronegative recipient was transplanted with a graft from a CMVseropositive donor. He received no anti-CMV prophylaxis. CMV infection was monitored by viral DNA quantitation in whole blood [3] twice a week during the first month post-transplantation, once a week during the second month post-transplantation and then twice a month. The patient developed asymptomatic CMV primary infection, consisting of an isolated CMV viraemia, 3 weeks after the transplantation. He therefore received a treatment with intravenous GCV (10 mg/kg/day) during 3 weeks, followed by a maintenance treatment with oral VGCV (900 mg/day). After an initial decrease, CMV load reincreased 2 months later and peaked over 100,000 copies/ml (Figure 1). At that time, the genotypic resistance testing, performed by conventional sequencing as previously described [4], revealed A594V and L595S changes in UL97 phosphotransferase, as mixed populations, conferring resistance to GCV. The antiviral treatment was then switched to intravenous FOS (90 mg/kg) twice a day during 3 weeks, and then once a day during 7 weeks. When FOS treatment was stopped (8 months post-transplantation) because of renal toxicity, CMV load was still detectable (109 copies/ml) and showed a new elevation with a peak at 35,855 copies/ml 1 month later (Figure 1). At that time, the genotypic resistance testing revealed several resistance mutations: L595S change (UL97) conferring resistance to GCV, P522S and L802M (UL54) associated with cross-resistance to GCV/CDV and GCV/FOS, respectively [1]. It is noteworthy that both the P522S change, elicited by prolonged GCV treatment, and the L802M change, elicited by FOS treatment, were detected about 2 weeks after the respective drugs were discontinued. Because of the CMV multidrug resistance, all antiviral treatments were stopped 10 months posttransplantation, the dose of cyclosporin A (CsA) was reduced and a treatment with everolimus, an inhibitor of mammalian target of rapamycine (mTOR), was initiated. CMV load remained approximately 10,000 copies/ml during 7 weeks and then decreased slowly and remained below 500 copies/ml (Figure 1). The CMV-specific CD8+ T-cell immunity was investigated by means of ELISPOT assays [5]. At 10 months post-transplantation, the results of functional assays were negative whereas they were highly positive at 14 months post-transplantation, indicating CMV-specific cellular immunity recovery. The patient remained free of symptoms during all the different episodes of CMV infection.
Among immunocompromised patients, the efficiency of antiviral drugs used for the treatment of CMV infections may be hampered because of the emergence of CMV resistance to antivirals. Moreover, the development of CMV multidrug-resistant infection, which remains uncommon but does occur, constitutes a clinically challenging complication and may contribute to difficult therapeutic management and adverse clinical outcome. In heart-transplant recipients, the incidence of CMV resistance to GCV was reported to be 1.5% and was significantly associated with CMV D+/R- status [6]. Two cases of CMV resistance to GCV and CDV have been previously reported in Australian patients [7]. To our knowledge, this is the first report describing a multidrug-resistant CMV infection after heart transplantation. The D+/R- heart-transplant recipient presented herein, considered at high-risk of CMV infection, did not receive VGCV prophylaxis. Instead, CMV load was monitored in blood at regular intervals in order to detect early viral replication and start a pre-emptive antiviral treatment. However, according to the international consensus guidelines on the management of CMV in SOT, this patient should have received universal VGCV prophylaxis [2]. Nevertheless, the emergence of CMV resistance has been reported in a high-risk heart transplant recipient despite VGCV prophylaxis [4]. Moreover, for the patient presented herein, the pre-emptive treatment should have been initiated probably earlier, once viral load had reached the threshold of 3 log copies/ml, as previously reported [4]. Different types of management of multidrug-resistant CMV infections have been reported so far in the literature [7–18] (Table 1). All patients presented immunodeficiency disorders: severe combined immunodeficiency (n=1), HIV infection (n=2), haematopoietic stem cell transplantation (n=1) and SOT (n=9). Among SOT recipients, 7/8 were at high-risk for developing CMV resistance to antivirals according to their D+/R- status [11–18]. CMV-associated clinical symptoms were observed in all patients except one [12]. In particular, retinitis occurred among seven of them. The patient presented herein remained free of symptoms despite multidrug-resistant CMV infection. In transplant recipients, CMV load in the initial phase of active infection and the rate of increase in viral load have been reported to correlate with CMV disease [19]. In the present case, the initial CMV load was 3.21 log and the rate of change in CMV load was 0.41 log genomes/ ml/day (Figure 1). According to the contour map provided by the authors, the patient had a risk of approximately 30% to develop CMV disease [19]. Most clinical reports of CMV drug resistance have underlined
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Figure 1. Kinetics of CMV load, anti-CMV and immunosuppressive treatments and emergence of CMV multidrug resistance
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Cytomegalovirus (CMV) DNA load (circles) measured by real-time PCR in whole blood samples is represented (logarithmic scale) during the post-transplantation period. The horizontal dashed line represents the limit of detection of CMV real-time PCR assay (that is, 25 copies/ml). The detection of the different CMV resistance mutations is indicated above the figure as follows: (+) presence of mutation in 100% of the detected sequence population, (±) presence of mutation as a mixed population and (-) absence of mutation. Durations of immunosuppressive and anti-CMV treatments are indicated by horizontal arrows at the top of the graph. FOS, foscarnet; GCV, ganciclovir; MMF, mycophenolate mofetil; VGCV, valganciclovir. Antiviral Therapy 20.2
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Prophylactic antiviral Curative treatments antiviral treatments
Resistance mutations in pUL97
Resistance mutations in pUL54 (associated Management of drug resistance) multidrug resistance Outcome
[11]
[17]
[13]
[7]
[15]
[18]
[16]
[12]
[14]
[10] [18]
[9]
[8]
Reference
a Pneumonitis, encephalitis, retinitis. bSmall intestine, stomach, pancreas, kidney. CDV, cidofovir; CMV-Ig, CMV immune globulin; D/R, donor/recipient CMV serostatus; F, female; FOS, foscarnet; GCV, ganciclovir; HSC, haematopoietic stem cell; IS, immunosuppression; m, month; M, male; NA, not available; SCID, severe combined immonodeficiency; Tx, transplantation; y, year.
3 m, M SCID Multiorgan diseasea None GCV, FOS M460V/I K513N (GCV/CDV) CMV-Ig Death CDV A594V T700A (FOS) L595S 42 y, M HIV infection Retinitis GCV GCV, FOS C603W F412C (GCV/CDV) Association of anti- Death CDV L802M (FOS) CMV approved drugs NA, M HIV infection Retinitis None GCV, FOS L595S Del 981-982 (GCV/CDV/FOS) None Progression of retinitis 47 y, F D-/R+ HSC Tx Fever VGCV GCV C592G L545S (GCV/CDV) Artesunate Favourable Neutropenia FOS, CDV D588N (GCV/CDV/FOS) 43 y, F D+/R- kidney Tx Pneumonitis VGCV GCV, FOS H520Q N408K (GCV/CDV) CMV-Ig Favourable Retinitis Fomivirsen A594V A834P (GCV/CDV/FOS) Leflunomide Colitis D413E (GCV/CDV) V787L (FOS) 68 y, F D+/R- kidney Tx None None VGCV, GCV None A834P (GCV/CDV/FOS) FOS, GCV Transplant rejection CMV-Ig 43 y, F D+/R- kidney Tx Retinitis VGCV VGCV, GCV, NA NA (GCV/CDV/FOS) CMV-Ig Favourable Uveitis FOS Leflunomide 60 y, M D+/R- kidney Tx Fever VGCV, GCV VGCV, GCV, C592G A987G (GCV/CDV) Artesunate Death Hepatic cytolysis FOS N408K (GCV/CDV) Encephalitis G841A (GCV/FOS) 68 y, F D+/R- lung Tx Retinitis VGCV, GCV VGCV, GCV, M460I A834P (GCV/CDV/FOS) Maribavir Favourable Duodenitis FOS, CDV L595S A987G (GCV/CDV) NA Lung Tx Colitis VGCV, GCV VGCV, GCV E596G F412S (GCV/CDV) CMV-Ig NA Duodenitis CDV L802M (FOS) IS reduction Gastritis A809V (GCV/FOS) 39 y, M D+/R+ lung Tx Pneumonitis VGCV GCV, FOS, A594T/V V715M (FOS) CMV-Ig Favourable Retinitis CDV C603W A987G (GCV/CDV) Leflunomide Colitis CMX001 Artesunate Letermovir 57 y, F D+/R- lung Tx Gastrointestinal disease VGCV VGCV, GCV, A594P K513N (GCV/CDV) VGCV, FOS Favourable FOS E756Q (FOS) CMV-Ig Leflunomide 34 y, F D+/R- multiorgan Txb Diarrhoea VGCV VGCV, GCV C603W L545S (GCV/CDV) Leflunomide Favourable Renal impairment FOS, CDV Q578H (FOS) IS reduction
CMV-associated Age, sex Context symptoms
Table 1. Overview of literature on the management of multidrug-resistant CMV infections in immunocompromised patients
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the highly symptomatic presentations [20], and most of multidrug-resistant CMV infections reported so far were associated with severe symptoms (Table 1). Nevertheless, drug resistance mutations have also been observed in relatively asymptomatic subjects [1]. Given those data, the absence of symptoms in the patient presented herein is not that surprising. Before the emergence of multidrug-resistant CMV infection, all patients received first-line (V)GCV followed by second-line FOS treatments and seven patients received third-line CDV treatment (Table 1). The retinitis of one patient was treated with the antisense nucleotide fomivirsen [14]. For each patient, CMV multidrug resistance was associated with resistance mutations located both in UL97 phosphotransferase, conferring GCV resistance, and in UL54 DNA polymerase. Two different genotypic resistance patterns were identified in UL54 DNA polymerase: either one mutation accounting by itself for multidrug resistance, for example, the deletion 981–982 or A834P change, or one mutation conferring cross-resistance to GCV/CDV and one mutation conferring resistance to FOS. Similarly to previous reports, CMV multidrug resistance emerged in the heart-transplant recipient presented here following antiviral treatments with (V)GCV and FOS, but no CDV [10,12,16], and was associated with several mutations located in UL97 phosphotransferase and UL54 DNA polymerase (Table 1). The kinetics of these resistance mutations during the study period in both viral enzymes and the detection of mixtures of wild type and resistant sequences indicate that CMV multidrug resistance is likely due to the infection of the patient by different CMV strains harbouring different resistance mutations (Figure 1). Cloning experiments or new-generation sequencing approaches may help to address this issue of single versus multiple infecting strains. The question of CMV multidrug resistance management in immunocompromised patients is still pending. A variety of strategies exist, but none of them has been evaluated adequately. Since it is well-recognized that patients lacking a specific immune response to CMV are at increased risk for developing CMV disease, one option consists in the improvement of antiviral host defences by the reduction of immunosuppression and the use of adjunctive therapies such as CMV-Ig or adoptive infusion of CMV-specific T-cells [2,20]. The immunomodulatory agents leflunomide and everolimus have been associated with lower CMV incidence [17,21,22]. Another strategy consists the use of experimental antiCMV agents currently under investigation in clinical trials: the CDV prodrug CMX001, the UL97 phosphotransferase inhibitor maribavir, the terminase complex inhibitor letermovir, or the antimalarial drug artesunate [1,2,20,23]. In the present case, the management of CMV multidrug resistance consisted the reduction Antiviral Therapy 20.2
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of CsA dose and the addition of everolimus, but the decrease of CMV load was very low. Indeed the recovery of CMV-specific T-cell immunity 14 months after transplantation is likely to have permitted the improvement of CMV infection. The prevention of the emergence of CMV resistance to antivirals remains highly required in transplant recipients by evaluation of risk factors, surveillance of CMV load, and use of prophylactic/pre-emptive antiviral treatments. Despite its relative infrequency, the management of CMV multidrug resistance has to be improved, in particular with new antivirals lacking cross-resistance with current drugs. In that field, maribavir and letermovir appear to be promising molecules [13,15]. Moreover, salvage therapies consisting in the choice of specific maintenance immunosuppressive drugs with antiviral properties, like leflunomide, may constitute an attractive alternative strategy [17,24,25].
Acknowledgements This work was supported in part by the Association pour la Recherche sur les Infections Virales (ARIV).
Disclosure statement The authors declare no competing interests.
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Accepted 18 June 2014; published online 25 June 2014
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