Severe cytomegalovirus infection in immunocompetent patients

Severe cytomegalovirus (CMV) infection is rare in previously healthy immunocompetent individuals; to our knowledge, only thirty-four such cases have been reported in the worldwide literature. Multiorgan involvement was associated with a high mortality rate among these patients. Disease that clinically involves only the liver or lungs could be fatal; in contrast, none of the patients with isolated central nervous system infection died. Although few patients were treated with specific antiviral therapy, five of six patients with severe infection recovered after receiving therapy with ganciclovir or foscarnet. The rarity of severe CMV disease in immunocompetent patients probably precludes the performance of a clinical trial to evaluate the efficacy of specific antiviral therapy. However, the historically poor prognosis in the absence of such therapy suggests that rapid diagnosis of CMV disease and early instigation of specific treatment may be important.

Outcomes in Transplant Recipients Treated With Foscarnet for Ganciclovir-Resistant or Refractory Cytomegalovirus Infection

BACKGROUND

Antiviral-resistant or refractory cytomegalovirus (CMV) infection is challenging, and salvage therapies, foscarnet, and cidofovir, have significant toxicities. Several investigational anti-CMV agents are under development, but more information is needed on outcomes of current treatments to facilitate clinical trial design for new drugs.

METHODS

Records of solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients at a single center over a 10-year period were reviewed retrospectively to characterize those who had received foscarnet treatment for ganciclovir-resistant or refractory CMV infection. Data were collected on virologic responses, mortality, and nephrotoxicity.

RESULTS

Of 39 patients (22 SOT, 17 HCT), 15 had documented ganciclovir resistance mutations and 11 (28%) of 39 had tissue-invasive CMV. Median duration of foscarnet was 32 days. Virologic failure occurred in 13 (33%) of 39 and relapses of viremia occurred in 31%. Mortality was 12 (31%) of 39 and was higher in HCT than SOT (P = 0.001), although ganciclovir resistance was more common in SOT (P = 0.003). Doses of ganciclovir or valganciclovir were low in 10 (26%) of 39 at some time before switching to foscarnet. Renal dysfunction occurred in 20 (51%) of 39 by end of treatment and in 7 (28%) of 25 after 6 months.

CONCLUSIONS

Outcomes of existing treatment for ganciclovir-resistant or refractory CMV are suboptimal, in terms of virologic clearance, renal dysfunction, and mortality. These data should provide background information for future clinical trials of newer antiviral agents.

A Randomized, Controlled Trial Comparing Ganciclovir to Ganciclovir Plus Foscarnet (Each at Half Dose) for Preemptive Therapy of Cytomegalovirus Infection in Transplant Recipients

Forty-eight patients who provided 2 consecutive blood samples that tested positive for cytomegalovirus DNA by polymerase chain reaction (PCR) were randomized to receive either full-dose ganciclovir (5 mg/kg intravenously [iv] twice daily) or half-dose ganciclovir (5 mg/kg iv once daily) plus half-dose foscarnet (90 mg/kg iv once daily) for 14 days. In the ganciclovir arm, 17 (71%) of 24 patients reached the primary end point of being CMV negative by PCR within 14 days of initiation of therapy, compared with 12 (50%) of 24 patients in the ganciclovir-plus-foscarnet arm (P = .12). Toxicity was greater in the combination-therapy arm. In patients who failed to reach the primary end point, baseline virus load was 0.77 log10 higher, the replication rate before therapy was faster (1.5 vs. 2.7 days), and the viral decay rate was slower (2.9 vs. 1.1 days) after therapy. Bivariable logistic regression models identified baseline virus load, bone-marrow transplantation, and doubling time and half-life of decay as the major factors affecting response to therapy within 14 days. This study did not support a synergistic effect of ganciclovir plus foscarnet in vivo.

Treatment of AIDS-associated gastrointestinal cytomegalovirus infection with foscarnet and ganciclovir: a randomized comparison

Patients with symptomatic gastrointestinal disease due to cytomegalovirus (CMV) were randomized to receive open-label ganciclovir (22) or foscarnet (26). Patients were stratified by disease site and concurrent gut infection. Response was assessed by a visual analogue score of symptoms, endoscopic appearances, histologic inflammation, and numbers of CMV inclusions. In each treatment group, 73% had a complete or good clinical response; 83% of foscarnet-treated and 85% of ganciclovir-treated patients showed response by endoscopy, and inclusion bodies disappeared from follow-up biopsies in 73% of these. Most patients (35) developed further evidence of CMV disease during follow-up. The time to progression was not significantly different between recipients (16 weeks) and nonrecipients (13 weeks) of maintenance therapy, although patients were not randomized to receive maintenance or not. Survival in both treatment groups was < 40 weeks and was unaffected by maintenance treatment. Both ganciclovir and foscarnet are effective first-line treatments for gastrointestinal (GI) CMV infection. Maintenance therapy does not prevent progression of disease.

Forscarnet vs ganciclovir for cytomegalovirus (CMV) antigenemia after allogeneic hemopoietic stem cell transplantation (HSCT): a randomised study

This trial was designed to compare foscarnet with ganciclovir as pre-emptive therapy for CMV infection in patients undergoing allogeneic hemopoietic stem cell transplant (HSCT). Thirty-nine patients were randomized to receive foscarnet 90 mg/kg every 12 h (n = 20) or ganciclovir 5 mg/kg every 12 h (n = 19) for 15 days at the time of development of CMVAg-emia. Primary-end points of the study were (1) outcome of CMVAg-emia; (2) progression to CMV disease; and (3) side-effects of treatment. The secondary end-point was transplant-related mortality (TRM). The two groups were comparable for diagnosis, status of disease, donor type, acute graft-versus-host (aGVHD) prophylaxis, interval between HSCT and CMVAg-emia and number of CMVAg positive cells; the donor and recipient age were borderline older in the foscarnet group. Increments of serum creatinine in the foscarnet group, and cytopenia in the ganciclovir group were controlled by reducing the administered dose: in the first 15 days of therapy 9/20 foscarnet and 10/19 ganciclovir patients had a dose reduction greater than 20% (P = 0.43). Clearance of CMVAg-emia was faster in the foscarnet group although with borderline statistical significance. Failures of treatment occurred in 3/20 patients in foscarnet group vs 8/19 patients in ganciclovir group (P= 0.06): causes of failure were the need for combination therapy to control antigenemia (1/20 vs 5/19), and reactivation during treatment for 2 vs 3 patients, respectively. CMV disease was diagnosed in 1 vs 2 patients (P = 0.5) who subsequently died. The actuarial 1-year TRM was 25 vs 12%, respectively (P = 0.3). This study suggests that foscarnet and ganciclovir are both effective for pre-emptive therapy of CMVAg-emia, although the number of failures would seem to be slightly higher in the ganciclovir patients. Side-effects are seen in both groups and can be managed with appropriate dose reduction.

Effect of foscarnet induction treatment on quantitation of human cytomegalovirus (HCMV) DNA in peripheral blood polymorphonuclear leukocytes and aqueous humor of AIDS patients with HCMV retinitis. The Italian Foscarnet Study Group

The aim of this study was to investigate peripheral blood polymorphonuclear leukocytes and, whenever possible, aqueous humor from 65 AIDS patients with ophthalmoscopically diagnosed human cytomegalovirus (HCMV) retinitis to determine (i) whether patients consistently carry viral DNA and (ii) to what extent foscarnet induction treatment decreases viral DNA levels. HCMV DNA was quantified by PCR using densitometric analysis of hybridization products obtained from external standards and a standard curve from which the number of genome equivalents of test samples, normalized by using an internal amplification control, was interpolated. Results showed that 56 of 65 patients (86.1%) were positive for HCMV DNA prior to induction treatment. Of 41 of the 56 patients (73.2%) whose blood had become DNA negative after induction, only 5 had a high viral load (> 5,000 genome equivalents per 2 x 10(5) polymorphonuclear leukocytes) prior to induction, whereas as many as 13 of the 15 (26.8%) patients remaining DNA positive after induction had a high viral load prior to induction. Finally, of the nine patients (13.8%) with DNA-negative blood prior to induction treatment, three were shifted to foscarnet from ganciclovir, while six were erroneously enrolled in the study. Pre- and postinduction aqueous humor samples were obtained from 12 patients; all of these were DNA positive prior to induction, whereas after induction, 4 became negative, 6 showed a marked decrease in viral DNA, and 2 had nearly stable low DNA levels. In conclusion, PCR is a valuable tool for etiologic diagnosis and monitoring of HCMV retinitis treatment in AIDS patients. HCMV DNA is consistently present in the blood and aqueous humor of all patients with HCMV retinitis. Foscarnet induction treatment is highly effective in suppressing or reducing DNA levels in both blood leukocytes and aqueous humor.

A pilot phase II study of alternate day ganciclovir and foscarnet in preventing cytomegalovirus (CMV) infections in at-risk pediatric and adolescent allogeneic stem cell transplant recipients

BACKGROUND

Prophylaxis with ganciclovir or foscarnet post allogeneic stem cell transplant (AlloSCT) reduces cytomegalovirus (CMV) disease. Combination ganciclovir/foscarnet is more effective than monotherapy in HIV patients with CMV retinitis. We hypothesized that alternate day ganciclovir and foscarnet for the prevention of CMV during the first 100 days after AlloSCT would be safe and effective.

PROCEDURE

Fifty-three pediatric and adolescent AlloSCT recipients receiving 57 AlloSCTs where donors and/or recipients were CMV seropositive received ganciclovir (5 mg/kg/48 hr) alternating with foscarnet (90 mg/kg/48 hr) from myeloid recovery (>or=ANC 750/mm3) until Day +100.

RESULTS

Patients were: M:F 31:22; age 6 years (0.8-18 years); donor sources: 25 related peripheral blood/bone marrow, 3 unrelated adult peripheral blood, 26 unrelated cord blood, and 3 related cord blood. GVHD prophylaxis included tacrolimus/mycophenolate mofetil (MMF). Median-nucleated and CD34 cell counts were 7.3x10(8)/kg and 5.07x10(6)/kg, respectively, for BM/PBSC; 4.07x10(7)/kg and 1.69x10(5)/kg, respectively, for CB. Despite a 36.5% probability of Grades II-IV acute GVHD, no patient developed systemic CMV disease. Five percent had Grade IV hematological toxicity that required discontinuation of ganciclovir. Twenty-five percent required discontinuation of foscarnet secondary to electrolyte abnormalities and/or renal dysfunction that were presumed to be multifactorial in origin. Probability of 1-year overall survival was 58.8%.

CONCLUSIONS

Alternate day ganciclovir/foscarnet in AlloSCT recipients where recipient and/or donor is seropositive appears to be tolerable and 100% effective in preventing CMV systemic disease. A randomized study will be required to determine if this approach is superior to other CMV prophylactic designs.

A dose-ranging study of daily maintenance intravenous foscarnet therapy for cytomegalovirus retinitis in AIDS

Thirty-two patients with AIDS and previously untreated cytomegalovirus retinitis completed an induction course of foscarnet, 60 mg/kg every 8 h for 14 days, had retinitis stabilize, and were then randomly assigned to receive foscarnet maintenance as either a 90- or 120-mg/kg/day infusion administered over 2 h. Median survival was 157 and 336 days for the 90- and 120-mg/kg/day groups, respectively (P < .001). In an independent, masked analysis of retinal photographs, median time to progression of retinitis was 31 versus 95 days (P = .13). Daily intravenous foscarnet at a dose of 120 mg/kg (adjusted for renal function) resulted in significantly longer survival and tended to increase time to retinitis progression compared to the standard 90-mg/kg/day maintenance dose. Although a substantial increase in the risk of serious toxicity at the 120-mg/kg/day dose was not observed, the small sample size in this trial limited the power to detect differences that might be clinically important.

Treatment of mucocutaneous herpes simplex virus infections unresponsive to acyclovir with topical foscarnet cream in AIDS patients: a phase I/II study

The efficacy and toxicity of foscarnet cream for the treatment of mucocutaneous herpes simplex virus lesions or lesions that were clinically unresponsive to systemic acyclovir treatment (median, 30.5 days) in AIDS patients were studied in a phase I/II, open-label, nonrandomized multicenter trial. In the study, 20 patients with advanced stages of AIDS were treated with foscarnet 1% cream five times a day for a mean duration of 34.5 days. Response of index lesions (n = 20) was judged to be completely healed (8 lesions), excellent (4 lesions), or good (1 lesion) in 65% of lesions. The median time to first negative herpes simplex virus culture of index lesion was 8 days. Among 15 patients with pain at baseline, 11 had complete resolution of pain and 2 had at least a 50% reduction. Clinical adverse events included skin ulceration (4 patients), application site reactions (3 patients), fever (3 patients), and headache (3 patients). Five (25%) patients developed new lesions due to herpes simplex virus at sites other than those being treated topically while enrolled in the study. Topical foscarnet 1% cream appears to be a safe and effective treatment for acyclovir-unresponsive mucocutaneous herpes simplex virus infection in AIDS patients.

Combination ganciclovir and foscarnet in the treatment of clinically resistant cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome

OBJECTIVE

To assess the clinical response and patient tolerance to daily infusions of both ganciclovir sodium and foscarnet sodium for the treatment of clinically resistant cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome.

DESIGN AND PATIENTS

Nine patients with clinically resistant cytomegalovirus retinitis who had shown progression of retinitis despite extended intravenous induction single-drug therapy or alternating therapy with induction doses of ganciclovir or foscarnet at 6 weeks were subsequently treated with a combination of ganciclovir and foscarnet. The dosing regimen for induction combination therapy was ganciclovir at 5 mg/kg every 12 hours and foscarnet at 60 mg/kg every 8 hours. Maintenance combination therapy was ganciclovir at 5 mg/kg every 12 to 24 hours and foscarnet at 90 to 120 mg/kg every day. Patients were observed closely for signs of a toxic effect or intolerance to the drug regimen.

RESULTS

All patients exhibited a favorable response to combination therapy, with complete healing of retinitis in 12 of 14 eyes and partial healing of retinitis with decreased border activity and a cessation of border advancement in two of 14 eyes. Two of the nine patients stopped receiving combination therapy before completion of the study owing to their dissatisfaction with the time commitment. The regimen was otherwise well tolerated, with no significant medical toxic effects attributable to the drugs requiring cessation of therapy.

CONCLUSIONS

Combination anticytomegalovirus therapy should be considered in those patients who have shown a poor clinical response to sustained single-drug induction therapy and alternating drug therapy. As survival time for patients with cytomegalovirus retinitis continues to improve, clinical resistance may become more common. Further work to delineate the optimal dosing and indications for combination therapy will be important.

Adverse effects and drug interactions of clinical importance with antiviral drugs

Most antiviral drugs are nucleoside analogues with potential teratogenic, embryotoxic, carcinogenic and antiproliferative activities. They must be administered with caution during pregnancy, because some are known teratogens (e.g. amantadine) and a similar propensity cannot be entirely excluded for others (e.g. aciclovir). Their adverse effects mostly involve bone marrow depression (e.g. granulocytopenia with ganciclovir, anaemia with zidovudine) or neurotoxicity (e.g. seizures with interferon-alpha, peripheral neuropathy with zalcitabine), although gastrointestinal effects are also seen. Idiosyncratic reactions include didanosine-induced acute pancreatitis. Only inosine pranobex is largely free from toxicity. Idoxuridine must be administered topically, given the severity of its systemic adverse effects. Drug interactions involving antiviral agents mostly reflect shared toxicity with other agents (e.g. neutropenia with ganciclovir and zidovudine, pancreatitis with didanosine and alcohol), although renal excretion or hepatic metabolism may be implicated. Given the possibility of severe adverse reactions and drug interactions, antiviral chemotherapy should only be used for potentially serious virus infections. Topical administration avoids systemic adverse effects but not mutagenic risks, and may result in exposure of individuals other than the patient (e.g. aerosolised ribavirin).

Acyclovir-resistant herpes zoster in human immunodeficiency virus-infected patients: results of foscarnet therapy

We retrospectively studied 18 consecutive cases of acyclovir-resistant zoster. All the patients had chronic skin lesions that failed to heal despite treatment with intravenous acyclovir (30 mg/[kg.d]) in 15 cases and oral acyclovir (4 g/d) in three cases for > 10 days. The mean CD4+ cell count was 20 x 10(6)/L. The mean number of previous zoster episodes was 1.53. Fifteen of the 16 patients evaluable for previous acyclovir treatment had received the drug. Thirteen patients were treated with intravenous foscarnet (200 mg/[kg.d]) for a mean of 17.8 days. Complete healing was observed in 10 (77%) of the 13 treated patients. Zoster relapsed after cessation of foscarnet therapy in five of the 10 responding patients. The median time to relapse was 110 days. Four patients died of varicella-zoster virus-associated visceral complications. These results show that acyclovir-resistant zoster has a poor prognosis but responds well to foscarnet therapy.

Combined foscarnet-ganciclovir treatment for cytomegalovirus infections after allogeneic hemopoietic stem cell transplantation

In a previous study, we showed that patients undergoing allogeneic hemopoietic stem cell transplantation (HSCT) who had cytomegalovirus (CMV) antigenemia with more than 4 CMV antigen-positive cells/200,000 have a high transplant-related mortality (TRM) rate, despite treatment with ganciclovir or foscarnet. In an attempt to reduce TRM, 32 allogeneic HSCT recipients, between the ages of 16 and 55 years (median, 35 years), with CMV antigenemia (> or = 5 positive cells) developing at a median interval from HSCT of 49 days, were given combination treatment with foscarnet and ganciclovir for 15 days. The prescribed dose was 180 mg/kg/day of foscarnet and 10 mg/kg/day of ganciclovir: the median administered dose in the first 15 days, after adjusting for creatinine levels and peripheral blood counts, was 64% for foscarnet and 53% for ganciclovir. Maintenance was given with foscarnet and ganciclovir on alternate days for an additional 2 weeks. Thirty-one of 32 patients were on cyclosporine, 30 were on systemic antibiotics, and 9 were on intravenous amphotericin. Median laboratory values on days 1 and 15 of treatment were 1.0 and 1.1 mg/100 ml creatinine, 5.7 x 10(9)/L, and 4.1 x 10(9)/L white blood cells, and 78 x lO(9)/L and 72 x 10(9)/L platelets. All patients cleared CMV antigenemia by day +15, although CMV antigenemia recurred in 5 patients on maintenance therapy and in 14 patients off maintenance therapy: the dose of foscarnet (but not ganciclovir) received in the first 15 days was significantly lower in patients in whom antigenemia recurred within 30 days (P=0.0002). Six patients died, one with interstitial pneumonia, one with multiorgan failure, and four with infections. Twenty-six patients survived 119-1051 days after transplant. The actuarial TRM rate at 1 year is 23%. Eighteen patients who had received unmanipulated bone marrow transplants from HLA-identical siblings were compared with 15 matched controls who had been treated with a single drug (either foscarnet or ganciclovir) for CMV antigenemia (> or = 5 cells): the actuarial 1 year TRM rate was 13% for patients receiving combined treatment, compared with 47% for controls receiving a single drug (P=0.02). This study shows that combined foscarnet-ganciclovir is one therapeutic option for allogeneic HSCT recipients who develop CMV antigenemia with a high number of CMV antigen-positive cells. Treatment can be given together with cyclosporine and antibiotics with appropriate dose reductions. It produces prompt clearing of CMV infection, and may reduce TRM rates in comparison to single-agent therapy.

Foscarnet-induced severe hypomagnesemia and other electrolyte disorders

OBJECTIVE

To report a case of possible foscarnet-induced severe hypomagnesemia and other electrolyte disorders.

CASE SUMMARY

An AIDS patient experienced an exacerbation of cytomegalovirus retinitis and was treated with foscarnet. The patient experienced muscle twitches, tremulousness, and anxiety on day 17 of foscarnet therapy. Laboratory results indicated hypomagnesemia, hypocalcemia, hypokalemia, and hypophosphatemia. After electrolyte supplementation and discontinuation of foscarnet, the symptoms resolved and laboratory indices returned to normal.

DISCUSSION

Electrolyte disorders associated with foscarnet are reviewed. Severe hypomagnesemia occurred in this patient and published literature is highlighted. In addition, known and/or possible mechanisms of the disorders are discussed.

CONCLUSIONS

It is probable that foscarnet contributed to the electrolyte disorders and symptomatology in this patient. Electrolytes must be monitored frequently during foscarnet therapy. Also, concomitant therapy with antianxiety medications that may mask the symptoms of electrolyte disorders should be undertaken with caution.

Local therapy for cytomegalovirus retinopathy

PURPOSE

We sought to understand better the efficacy and risks of local therapies (direct placement of drug into the eye) for the treatment of cytomegalovirus retinopathy. This understanding can be used to design rational treatment regimens, to formulate indications for use of local therapy, and to establish criteria for assessment of future results in this area.

METHODS

We collected information about local therapies through a review of published literature.

RESULTS

Intraocular injection of ganciclovir and foscarnet and implantation of intraocular devices that slowly release ganciclovir are able to decrease the activity of cytomegalovirus retinopathy lesions and prevent their enlargement for variable periods of time. The time to disease progression (lesion enlargement) may be longer with intraocular devices than with current treatments using intravenously administered antiviral drugs. Local therapies have many advantages (for example, convenience, reduced cost, and lack of systemic toxicity), but there are potential disadvantages, including endophthalmitis, increased rates of retinal detachment, and development of nonocular cytomegalovirus disease and cytomegalovirus retinopathy in fellow, uninvolved eyes.

CONCLUSIONS

Local therapies are effective for the treatment of cytomegalovirus retinopathy, but their relative risks and benefits, when compared with those of intravenous drug therapy, have yet to be fully evaluated. We anticipate that local therapy will be an important treatment modality for selected patients with cytomegalovirus retinopathy. Indications include the use of local therapy as an alternative therapy for patients who are unable to receive systemic therapy (intolerance to intravenous or oral medication, or lack of intravenous access) and as supplementation in patients whose retinal disease is incompletely controlled by maximum tolerated systemic medications. The use of local therapy as sole initial treatment in lieu of systemic therapy remains controversial. Its most useful role may be in conjunction with oral forms of antiviral drugs now in development.

Nephrogenic diabetes insipidus and renal tubular acidosis secondary to foscarnet therapy

Foscarnet is used as therapy of cytomegalovirus (CMV) infection in immunosuppressed subjects. We present a patient with human immunodeficiency virus infection under treatment with foscarnet for CMV retinitis who complained of thirst and polyuria. Laboratory data showed hypernatremia with increased plasma osmolality and metabolic hyperchloremic acidosis. A water deprivation test demonstrated a nephrogenic diabetes insipidus. Other laboratory studies, including urine pH, anion gap, titratable acidity, and bicarbonate, showed a distal tubular acidification defect. All abnormalities were transient, with recovery a few days after foscarnet withdrawal. No cases of renal acidosis, and only one case of nephrogenic diabetes insipidus, has been previously reported as a complication of foscarnet treatment. Our patient developed both nephrogenic diabetes insipidus and renal tubular acidosis with a temporal pattern that demonstrated a link between foscarnet therapy and these abnormalities.

Foscarnet-induced crystalline glomerulonephritis with nephrotic syndrome and acute renal failure after kidney transplantation

Foscarnet nephrotoxicity has been reported to be associated with acute tubulointerstitial nephritis. Crystals in glomerular capillary lumens have also been observed in patients with acquired immunodeficiency syndrome who were treated with foscarnet for cytomegalovirus disease. We describe a kidney transplant recipient who developed a nephrotic syndrome with microscopic hematuria and nonoliguric acute renal failure within 15 days after starting foscarnet therapy for cytomegalovirus infection. A kidney biopsy specimen showed the presence of crystals in all glomeruli and in proximal tubules. Fourier transform infrared microscopy analysis demonstrated that crystals were made from several forms of foscarnet salts: mixed calcium and sodium salts, and unchanged trisodium foscarnet salts. Renal function and proteinuria spontaneously improved, and a second transplant biopsy performed 8 months after the first one revealed fibrotic organization of half of the glomeruli and of interstitial tissue, and crystal vanishing. We were thus able to provide proof of the possible precipitation of foscarnet in a transplanted kidney.

Identification of crystals in kidneys of AIDS patients treated with foscarnet

Three acquired immune deficiency syndrome patients given foscarnet to treat cytomegalovirus retinitis developed renal failure with crystal deposits within the renal glomeruli. We identified these crystals as a mixture of sodium salt, calcium salt, and a mixed salt containing both sodium and calcium ions. This composition has not been previously reported. Foscarnet can complex available ionized calcium and secondarily precipitate in glomeruli. The percentage of complexing depends on calcium concentration in serum and the poor calcium salt solubility.

Foscarnet prophylaxis of cytomegalovirus infections in patients undergoing allogeneic bone marrow transplantation (BMT): a dose-finding study

This is a dose-finding study using foscarnet for CMV prophylaxis after allogeneic bone marrow transplantation (BMT) in 20 high risk patients (unrelated donors, or T cell depleted, and/or advanced disease). Foscarnet was started on day +1 after BMT and continued until day +100. We explored four different dose levels, patients being entered at the lowest dose level until one patient experiences CMV-reactivation, identified as two consecutive positive CMV antigenemias (CMVAg-emia). The four dose levels expressed as mg/kg/day between days 1 and 30 (induction) and between days 31 and 100 (maintenance) were respectively: dose level I = 60/30 (n = 5); dose level II = 120/60 (n = 4); dose level III = 120/90 (n = 5) and dose level IV = 120/120 (n = 6). All patients showed engraftment: PMN > or =0.5 x 109/l at a median interval of 16, 21, 17, 15 days after BMT, and Plt > or =30x10(9)/l on days 19, 16, 17, 17 respectively. CMVAg-emia was seen in 10 patients at a median interval of 53 days post-BMT (range 33-89) with a median of 10 CMV antigen+ cells (range 1-16). There was a dose effect of foscarnet on CMVAg-emia: respectively 4/5 patients (80%), 2/4 (50%), 3/5 (60%) and 1/6 (18%) at dose levels I, II, III, IV (P = 0.1). CMV disease was seen in 3/9 (33%) at dose levels I, II and 0/11 at dose levels III, IV (P = 0. 07). The median number of CMV antigen-positive cells at diagnosis of CMV infection was different: 13 in dose levels I-II and two in dose levels III-IV (P = 0.01). Increased creatininine was seen in 15 patients with a mean of 1.8 mg% (range 1.5-5.7) and was the cause of discontinuation in nine patients (45%). Renal toxicity was reversible in all nine patients. Overall actuarial TRM at 2 years was 31%: 47% for patients at dose levels I-II and 19% for patients at dose levels III-IV. In conclusion, foscarnet exhibits a dose-dependent prophylactic effect on CMVAg-emia, CMV disease and transplant-related mortality with acceptable and reversible renal toxicity.

The development of cytomegalovirus encephalitis in AIDS patients receiving ganciclovir

PURPOSE

Cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS) requires lifelong therapy with either intravenous ganciclovir sodium or foscarnet sodium. From June 1989 through February 1992, seven patients with AIDS were diagnosed to have CMV retinitis, and all were treated with ganciclovir. Five of the seven developed abrupt preterminal mental status changes. All five with mental status changes received anti-CMV therapy until the time of death. Autopsies were performed in all cases to determine the cause of mental status changes.

PATIENTS AND METHODS

Five patients with AIDS and newly diagnosed CMV retinitis. Retrospective case analyses with autopsies. All five patients were treated with gangciclovir immediately upon the diagnosis of CMV retinitis and received ganciclovir at standard dosages until death.

RESULTS

Four patients had clinically stable retinitis throughout the entire course of ganciclovir therapy. In the fifth patient, because of fundoscopic deterioration, foscarnet therapy was initiated 1 month prior to death. Cerebrospinal fluid analysis and magnetic resonance imaging, although abnormal, were not diagnostically specific. Neuropathologic examination revealed fulminant diffuse CMV encephalitis in all patients, with prominent ependymal and periventricular necrosis.

CONCLUSIONS

These results suggest that while ganciclovir therapy may clinically stabilize CMV retinitis in patients with AIDS, it does not appear to prevent the development of, or be effective in the treatment of, CMV encephalitis. Thus, clinicians should consider the diagnosis of CMV encephalitis in patients receiving ganciclovir who develop mental status changes and, if possible, alter therapy accordingly.

Current management of cytomegalovirus disease in patients with AIDS

Cytomegalovirus (CMV) infection is common in both homosexual and heterosexual HIV-infected patients, and causes disease in a substantial proportion of patients with AIDS and very low CD4+ cell counts. Both ganciclovir, an analog of the nucleoside guanosine, and foscarnet, an analog of pyrophosphate, are licensed for treatment of CMV retinitis. They may also have a role in the treatment of gastrointestinal disease caused by CMV. In the Studies of Ocular Complications of AIDS comparative trial the two agents were equally effective against CMV retinitis, but patients receiving foscarnet had significantly longer survival, even after adjusting for covariates including antiretroviral therapy. Ongoing studies are evaluating higher dosages of foscarnet for maintenance therapy and combined therapy with ganciclovir and foscarnet. Tolerance of ganciclovir therapy has been facilitated by adjunctive therapy with colony-stimulating factors. Because both ganciclovir and foscarnet must be administered by intravenous infusion and are associated with significant toxicities, other anti-CMV agents are under active development, including HPMPC and an oral formulation of ganciclovir. Management of CMV retinitis involves individualizing therapy, balancing side effects and administration requirements, and, in many clinical settings, the overall cost of treatment.

Treatment of Refractory CMV-Infection Following Hematopoietic Stem Cell Transplantation with the Combination of Foscarnet and Leflunomide

BACKGROUND

Treatment of cytomegalovirus (CMV) disease after allogeneic hematopoietic stem cell transplantation (HSCT) is limited by toxicities of current antiviral drugs and the occurrence of drug resistant strains. Leflunomide, an immunosuppressive agent used for treatment of rheumatoid arthritis, also has activity against CMV by impairing viral assembly. Here we report the control of refractory CMV disease by the combined use of foscarnet and leflunomide.

PATIENTS AND RESULTS

A 1S-year-old boy with juvenile myelo-monocytic leukemia (JMML) received an allogeneic HSCT with bone marrow stem cells from a mismatched, unrelated donor (MMUD, recipient and donor CMV-positive). CMV-reactivation two months post transplantation (Tx) could only be controlled by the use of cidofovir. Because of secondary graft failure, the boy received a second HSCT with peripheral blood stem cells (PBSC) of the same donor after overall 6 months. CMV-infection was noticed three weeks later, associated with a considerable rise of both CMV-copy number and pp65-antigen. Since reinduction with cidofovir was ineffective and ganciclovir not warranted due to the history of graft failure, the child then received a combination of foscarnet/leflunomide, leading to a rapid decline of his CMV-copy number and to an afebrile state. Hematological, hepatic or renal toxicities were not observed.

CONCLUSION

This case report suggests that leflunomide may be of use in the management of transplant recipients with CMV-infection refractory or intolerant to conventional antiviral therapy.

A double-blind placebo-controlled crossover trial of intravenous magnesium sulfate for foscarnet-induced ionized hypocalcemia and hypomagnesemia in patients with AIDS and cytomegalovirus infection

Foscarnet (trisodium phosphonoformate hexahydrate) is an antiviral agent used to treat cytomegalovirus disease in immunocompromised patients. One common side effect is acute ionized hypocalcemia and hypomagnesemia following intravenous administration. Foscarnet-induced ionized hypomagnesemia might contribute to ionized hypocalcemia by impairing excretion of preformed parathyroid hormone (PTH) or by producing target organ resistance. Prevention of ionized hypomagnesemia following foscarnet administration could blunt the development of ionized hypocalcemia. To determine whether intravenous magnesium ameliorates the decline in ionized calcium and/or magnesium following foscarnet infusions, MgSO(4) at doses of 1, 2, and 3 g was administered in a double-blind, placebo-controlled, randomized, crossover trial to 12 patients with AIDS and cytomegalovirus disease. Overall, increasing doses of MgSO(4) reduced or eliminated foscarnet-induced acute ionized hypomagnesemia. Supplementation, however, had no discernible effect on foscarnet-induced ionized hypocalcemia despite significant increases in serum PTH levels. No dose-related, clinically significant adverse events were found, suggesting that intravenous supplementation with up to 3 g of MgSO(4) was safe in this chronically ill population. Since parenteral MgSO(4) did not alter foscarnet-induced ionized hypocalcemia or symptoms associated with foscarnet, routine intravenous supplementation for patients with normal serum magnesium levels is not recommended during treatment with foscarnet.

Minimising the dosage-limiting toxicities of foscarnet induction therapy

This article suggests ways to manage the dose-limiting adverse reactions caused by foscarnet so that this agent may be used with confidence as first-line therapy in patients with cytomegalovirus (CMV) disease. Foscarnet (trisodium phosphonoformate) has been used for the treatment of CMV disease in patients who are infected with HIV. Some physicians who treat patients with CMV infection are reluctant to use foscarnet because of the serious adverse effects that may occur, especially during the induction period. The most frequently reported serious adverse effects are nephrotoxicity, electrolyte disturbances, nausea, penile ulcerations and seizures. The nephrotoxicity associated with foscarnet is attributable to renal tubular damage, and may be minimised by calculating and infusing the appropriate dose after hydrating the patient. Monitoring serum electrolyte levels and replacing electrolytes before symptoms occur may limit the development of dosage-limiting toxicities. Nausea occurring during foscarnet infusions may be ameliorated by using antiemetics and slowing the infusion rate. Seizures associated with the use of this agent are mostly a result of the simultaneous presence of other CNS pathologies. Penile ulcers are best managed by stopping the infusion until the ulcers heal; they may be prevented by paying careful attention to personal hygiene.

Nephrotoxicity of antiviral therapies

An ever-increasing variety of antiviral medications are being used clinically for an array of viral infections ranging from hepatitis to HIV. Some of these medications, such as acyclovir and foscarnet, have significant nephrotoxicity, whereas others are associated only rarely with renal failure. The spectrum of renal lesions associated with antiviral nephrotoxicity suggests that these medications may cause renal failure by affecting tubular cells or glomeruli. In most instances of antiviral-related nephrotoxicity, discontinuation of the offending agent results in a rapid return to normal renal function.