INTRODUCTION — Focal segmental glomerulosclerosis (FSGS) is a histologic diagnosis that may be found either without an identifiable cause (in which case it is called "idiopathic" or "primary") or in response to previous glomerular injury, glomerular hypertension, or hypertrophy ("secondary") [1]. Primary FSGS may present acutely with overt nephrotic syndrome with hypoalbuminemia and edema or, less often, insidiously with less dramatic manifestations, possibly related to the underlying histologic variant. In contrast, secondary FSGS most often presents as asymptomatic proteinuria without hypoalbuminemia or edema [2]. Distinguishing between primary and secondary disease is particularly important because of the markedly different approach to therapy in the two disorders. (See "Classification and pathogenesis of focal segmental glomerulosclerosis", section on 'Secondary FSGS'.)
Primary FSGS was previously considered to be largely unresponsive to immunosuppressive therapy; however, glucocorticoids, cyclosporine, and other immunosuppressive agents have been used with considerable therapeutic success. In contrast, immunosuppression is not indicated in secondary FSGS.
Renin-angiotensin-aldosterone system blockade (with angiotensin converting enzyme [ACE] inhibitors or angiotensin receptor blockers [ARBs]) reduce proteinuria and slow progression in proteinuric kidney diseases, and are therefore likely to be beneficial in primary and secondary FSGS. Among the rare patients with FSGS related to malignancy, effective therapy of the malignancy may lead to remission of the proteinuria [3].
This topic will review the prognosis and treatment of primary FSGS in adults, focusing on patients with nephrotic range proteinuria. The causes of FSGS and the treatment of children with FSGS are discussed separately. (See "Classification and pathogenesis of focal segmental glomerulosclerosis" and "Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults" and "Treatment of idiopathic nephrotic syndrome in children".)
The following discussion does not apply to collapsing FSGS, which may be associated with HIV and a variety of other conditions. This variant is discussed separately. (See "Collapsing focal segmental glomerulosclerosis and other renal diseases associated with HIV infection" and "Collapsing focal segmental glomerulosclerosis not associated with HIV infection".)
PROGNOSIS — The potential efficacy of therapy must be considered in relation to the natural history of the disease. Untreated primary FSGS often follows a progressive course to end-stage renal disease (ESRD). The rate of spontaneous complete remission among patients with nephrotic syndrome is unknown, but is probably less than 10 percent. Spontaneous remission is more likely to occur among patients with normal kidney function and non-nephrotic proteinuria [4].
Previously, treatment was not considered to substantially improve the prognosis of FSGS. However, longer courses of treatment have resulted in response rates of up to 70 percent and improved overall prognosis. Whether the outcome of patients who present with a substantial reduction in kidney function can be altered is less clear. (See 'Treatment' below.)
Prognostic factors — Factors that appear to influence response to treatment and/or prognosis principally include degree of proteinuria and renal dysfunction, histologic findings, and the response to therapy.
Degree of proteinuria — Patients with the nephrotic syndrome (proteinuria ≥3.0 or 3.5 g/day and low plasma albumin concentration) have five-year renal survival rates of 60 to 90 percent, and 10-year renal survival rates of 30 to 55 percent [5-8]. Massive proteinuria (>10 g/day), when unresponsive to treatment, is associated with an even worse prognosis, with most patients progressing to ESRD within five years [5]. In contrast, renal survival is much better in patients without nephrotic syndrome, especially when this is associated with normal renal function (over 85 percent renal survival at 10 years) [9].
The rate of spontaneous complete remission among patients with nephrotic range proteinuria is unknown, since most patients are treated. It is probably less than 10 percent; slightly higher spontaneous remission rates in some reports may reflect more widespread use of ACE inhibitors [5,10-12].
Severity of renal dysfunction — More severe renal dysfunction at presentation is generally associated with worse renal survival [13-15]. In one series, for example, patients with a plasma creatinine concentration of greater than 1.3 mg/dL (115 micromol/L) had a significantly decreased 10-year renal survival (27 versus 100 percent for those with a lower plasma creatinine) that was independent of the degree of proteinuria [14]. Worse renal function at presentation (unless it is acute) is generally associated with a greater extent of fibrosis on biopsy (reflecting more severe disease, disease of longer duration, or other factors such as hypertension or aging); therefore, it is less likely to respond to therapy.
Histologic findings — The presence of interstitial fibrosis at the time of presentation uniformly predicts poor renal survival, although this may reflect secondary FSGS in some cases [7,15-17]. The collapsing variant is particularly associated with a worse prognosis and is often considered a different disorder. Although the association of other histologic findings with prognosis is less clear, patients with segmental scarring at the tubular pole of the glomeruli, the so-called "glomerular tip lesion" (picture 1), have been considered more likely to respond to steroid therapy or to spontaneously remit (if renal function is normal), although this remains under considerable debate, and the presence of this lesion does not guarantee responsiveness [4,17-20]. (See "Classification and pathogenesis of focal segmental glomerulosclerosis".)
Interestingly, focal "global" sclerosis (eg, lesions that involve most or all of the glomerular tuft, not just segments) was associated with steroid responsiveness in a small study of children [21]. One possible explanation is that these patients actually had minimal change disease and the totally sclerotic glomeruli reflected prior damage. (See 'Glucocorticoid resistance' below.)
Response to therapy — The strongest prognostic indicator of outcome is the initial response to therapy regardless of the type of histology. Response is reported in terms of degree of reduction in proteinuria [5,13,22,23]. We propose the following definitions:
Some investigators also include normalization of the plasma albumin concentration in the definition of response. Patients who undergo partial or complete remission have a much better chance of renal survival (approximately 80 versus <50 percent at 10 years in nonresponders and untreated patients) [5,6,9,11,13,16,18,24].
General outcomes with respect to response to therapy, including the prognosis associated with partial remissions and relapses, were perhaps best shown in a retrospective study of 281 FSGS patients with the nephrotic syndrome who were followed for a minimum of one year in the Toronto Glomerulonephritis Registry [13]. Two-thirds of the patients received immunosuppressive therapy, including high-dose glucocorticoids (50 percent), cytotoxic agents (19 percent), or cyclosporine (12 percent). Over one-half of patients also received an ACE inhibitor or ARB.
At a median follow-up of 64 months, a complete, partial, or no remission was observed in 20, 41, and 39 percent, respectively. The time to remission was 12 to 14 months. Relapses occurred less frequently in those who had a complete remission (36 versus 52 percent among partial responders). Renal failure occurred in 6, 18, and 45 percent of patients with a complete, partial, or no remission, respectively. Patients who remained in remission had a slower rate of decline in renal function and a lower risk of renal failure compared to those who experienced a later relapse.
Disease progression — Disease progression, either by worsening renal function or, in some studies, histologic parameters, may occur despite partial remission of proteinuria. Some patients have a modest increase in the plasma creatinine concentration and, on repeat renal biopsy, an increased number of glomeruli with segmental or global sclerosis and more severe tubulointerstitial disease. This may be in part due to bias in the selection of patients for repeat biopsy and tissue sampling bias given the focal nature of the disease. However, it may also reflect a low level of continued disease activity, healing of previous injury, or secondary hemodynamic damage (which may be minimized by administration of an ACE inhibitor or ARB). (See 'Nonimmunosuppressive therapy' below.)
TREATMENT — Although less responsive than minimal change disease, primary FSGS appears to respond to glucocorticoids, as well as other agents [16]; however, more prolonged glucocorticoid therapy than in minimal change disease is generally required to induce remission.
For the treatment of steroid-resistant or relapsing disease, cyclosporine is most commonly used, although other agents, including cyclophosphamide, mycophenolate, and sirolimus, have been tried with various degrees of response in a small number of cases.
Although not specifically studied in primary or secondary FSGS, ACE inhibitors or ARBs reduce proteinuria and slow progression in proteinuric kidney diseases, and are therefore indicated in all patients with primary FSGS whether or not immunosuppressive therapy is provided. In addition, patients with nephrotic syndrome are often hypercholesterolemic and require appropriate statin therapy. (See 'Nonimmunosuppressive therapy' below.)
These recommendations do not apply to collapsing FSGS, the treatment of which is discussed separately. (See "Collapsing focal segmental glomerulosclerosis and other renal diseases associated with HIV infection" and "Collapsing focal segmental glomerulosclerosis not associated with HIV infection".)
Initial immunosuppressive therapy — The recommendations for initial therapy with prednisone are solely based upon observational studies and the authors' clinical experience. There are no randomized trials comparing prednisone or other agents to placebo for initial therapy of primary FSGS. Prednisone induces complete or partial remission in 40 to 80 percent of patients with relatively preserved renal function and, as noted above, responders have better long-term outcomes. (See 'Glucocorticoid studies' below.)
It is not possible to confidently predict at presentation which patients will respond to steroids. In addition, a small number of patients with primary FSGS will spontaneously remit and have a good prognosis and will not require immunosuppressive therapy. These patients, however, are also not predictable at presentation. Perhaps more important to weigh are the risks and benefits of steroid therapy in the elderly patients or those with co-morbid conditions.
We generally provide immunosuppressive therapy to patients with primary FSGS who present with nephrotic range proteinuria. Prednisone is usually administered for a minimum of 12 to 16 weeks [25,26]. The efficacy of immunosuppression in patients with significantly decreased kidney function (eg, GFR <25 to 35 mL/min per 1.73 m2) is unclear. The decision should take into consideration the acuity of the renal failure (better response with acute disease), the findings on renal biopsy (eg, poor response with the presence of significant tubulointerstitial fibrosis and glomerulosclerosis), and the patient's risk for adverse consequences related to immunosuppression. (See 'Monitoring response to and duration of therapy' below.)
We generally do not initiate immunosuppressive therapy in patients with the following clinical features:
These patients should receive nonimmunologic therapy with ACE inhibitors and/or ARBs to slow disease progression. (See 'Nonimmunosuppressive therapy' below.)
Although data are limited, we may use cyclosporine or tacrolimus as initial therapy, in conjunction with low dose prednisone, in patients at increased risk for glucocorticoid-associated toxicity. Potential candidates for this approach are the obese, patients with diabetes or at high risk for developing diabetes, patients with severe osteoporosis, and older patients. We avoid using calcineurin inhibitors in patients who have significant vascular or interstitial disease on renal biopsy, or an estimated GFR <40 mL/min per 1.73 m2 because of the potential nephrotoxicity of these drugs. (See "Major side effects of systemic glucocorticoids" and "Cyclosporine and tacrolimus nephrotoxicity".)
Glucocorticoid studies — Nonrandomized retrospective studies utilizing a variety of glucocorticoid doses have reported 40 to 80 percent rates of complete (proteinuria <200 or 300 mg/day) or partial remission (variably defined as <2 to 3.5 g/day and/or ≥50 percent decrease in proteinuria) [5,10,11,13,16,18,24,27]. One report, for example, evaluated the course of 55 adults with a mean creatinine clearance of 90 mL/min at a mean follow-up of 11 years; 18 were treated with prednisone, seven also received cyclophosphamide, and the remainder were not treated [10]. Among the 18 treated patients, 8 (44 percent) achieved complete remission (one received cyclophosphamide in combination with glucocorticoids, another as secondary treatment after relapse), compared to 4 of 37 (11 percent) untreated patients (two of whom were never nephrotic). ESRD occurred significantly less often in treated nephrotic patients (29 versus 53 percent in untreated nephrotic patients).
Another study described renal survival in 60 nephrotic and 21 non-nephrotic patients with FSGS; the serum creatinine at biopsy was 2.3 and 1.8 mg/dL (203 and 160 micromol/L) among nephrotic and non-nephrotic patients, respectively [5]. Half of the nephrotic patients were treated with prednisone. The 5- and 10-year renal survival in the non-nephrotic patients was 92 percent, compared with 76 and 57 percent among nephrotic patients. Among the treated nephrotic patients, half responded. The 5- and 10-year renal survival among responders was 100 percent, compared with 65 and 40 percent among nonresponders, respectively. Similar findings have been described by others [18].
In addition to the presence of nephrotic syndrome, the level of kidney function was predictive of response to treatment in some [11,13,27], but not all studies [5,10]. In the one study providing a stratified analysis, remission was achieved in only 5 of 21 patients with a serum creatinine >1.4 mg/dL (124 micromol/L) compared to 36 of 60 with lower serum creatinine concentrations [27].
Race may also affect the response to steroid therapy. In a retrospective review of 72 individuals with primary FSGS, of whom 65 were African Americans, 60 percent received steroid therapy [28]. The mean maximum dose was 60 mg/day, and duration including taper was almost one year. At a mean follow-up of approximately four years, 26 and 21 percent of the treated and untreated patients, respectively, reached ESRD, all of whom were African American. However, this retrospective study does not preclude the possibility that African Americans might respond to steroids; as a result, we feel that race alone should not be an issue in initiating therapy.
Prednisone dose — The optimal dose and duration of therapy are unknown. In many cases, an overall course of treatment of at least six to eight months is required [16,23], and complete remission may not be attained for 12 months or longer [27]. Shorter courses (≤two months) result in much lower remission rates (20 to 30 percent) and may have led to the earlier belief that this condition was not steroid responsive [5].
There are no randomized trials to guide the dose and duration of glucocorticoid therapy. The following dosing recommendations are extrapolated from doses used with apparent success in some of the observational studies and in trials of other renal diseases:
We prefer daily dosing for initial therapy in patients with no contraindications, since failure to respond to alternate day dosing would necessitate conversion to daily dosing and result in prolongation of the steroid course. Despite this general recommendation, alternate day dosing may be a better option in patients at higher risk of complications from glucocorticoids.
Monitoring response to and duration of therapy — There are no specific guidelines for monitoring the response to therapy, but it seems reasonable to obtain routine blood chemistries, including a plasma creatinine concentration for estimation of GFR, and to follow the urine protein-to-creatinine ratio. During the initial two to three months of therapy, we evaluate for a response (or toxicity) at two to four week intervals. Prior to tapering immunosuppression, we confirm the level of proteinuria with a 24-hour urine collection. Once drug therapy is stabilized and/or is being tapered, we monitor at one- to two- month intervals. (See "Patient information: Collection of a 24-hour urine specimen (Beyond the Basics)".)
The subsequent management of patients initially treated with prednisone is based upon the degree and rapidity of response (eg, faster taper for patients who achieve a quick remission), whether full or partial remission is achieved, and the degree of steroid toxicity:
Among patients on prolonged prednisone therapy, the risk of adrenal suppression during tapering must be considered. (See "Glucocorticoid withdrawal".)
Glucocorticoid resistance — As mentioned above, patients who will respond generally start to show some reduction in protein excretion within the first 8 to 12 weeks of therapy. Thus, patients with little or no reduction in protein excretion at 12 to 16 weeks are considered to be steroid-resistant [9,16,18].
Factors that appear to be associated with a lower likelihood of response to steroids are significant tubulointerstitial disease on renal biopsy (which may reflect secondary FSGS in some cases), and an elevated plasma creatinine concentration [5,6,16]. In addition, patients with massive proteinuria (>10 g/day) may be less likely to respond [6,29].
Although certain podocin mutations are associated with steroid-resistance in children, the relevance of these findings to adults is uncertain, and we do not test routinely for this mutation.
At present, it is not possible to confidently predict at presentation which patients with primary FSGS will respond to steroid therapy. Even the finding of severe tubulointerstitial fibrosis must be interpreted with caution, given the focal nature of the disease. As a result, such patients should receive a trial of glucocorticoids, unless they are at markedly increased risk of steroid-induced side effects or have a substantial reduction in estimated glomerular filtration rate. (See 'Initial immunosuppressive therapy' above.)
Calcineurin inhibitors — In patients at increased risk for glucocorticoid-associated toxicity, we occasionally use cyclosporine or tacrolimus in conjunction with low dose prednisone as initial therapy, although data evaluating this strategy are limited. We avoid using calcineurin inhibitors in patients who have significant vascular or interstitial disease on renal biopsy, or an estimated GFR <40 mL/min per 1.73 m2 because of the nephrotoxicity of these drugs.
Studies on cyclosporine are restricted to steroid-resistant or steroid-dependent primary FSGS, while there is only one uncontrolled study of initial therapy with tacrolimus. In this report, six patients with a mean protein excretion of 11 g/day who were being treated with an ACE inhibitor or ARB but no immunosuppression received tacrolimus (initial dose 2 mg twice daily, adjusted to 12-hour trough levels of 4 to 7 ng/mL) [33]. All entered a partial remission with >75 percent reduction in proteinuria (to a mean of 2.8 g/day) within a mean of six months. GFR declined initially in two patients from >90 to 50 mL/min per 1.73 m2, but subsequently stabilized. The optimal duration of therapy with this approach is uncertain.
We favor the use of cyclosporine rather than tacrolimus based upon more extensive experience with its use. The dose and monitoring regimen is the same as that used for steroid-dependent and steroid-resistant disease. (See 'Cyclosporine' below and 'Tacrolimus' below.)
Relapsing disease — Following cessation of initial therapy, some patients experience a recurrence of nephrotic range proteinuria. The approach to this problem varies with the response to initial therapy and the time to relapse:
Steroid-dependent and steroid-resistant FSGS — Recommendations for the therapy of steroid-dependent and steroid-resistant FSGS are based upon a few randomized controlled trials examining the benefits of cyclosporine versus placebo and other agents, as well as observational and uncontrolled studies.
FSGS is considered steroid-dependent if a patient relapses while on therapy (or requires continuation of steroids to maintain remission) and steroid-resistant if there is little or no reduction in proteinuria after 12 to 16 weeks of adequate prednisone therapy or if there is some reduction in proteinuria with more prolonged therapy that does not meet the criteria for partial remission. (See 'Response to therapy' above.)
We suggest that initial therapy of steroid-dependent or steroid-resistant FSGS consist of cyclosporine combined with low-dose prednisone. Among those unresponsive to this combination, additional agents have been evaluated, including cyclophosphamide, chlorambucil, tacrolimus, mycophenolate, and sirolimus [34]. We prefer mycophenolate due to its lower toxicity compared with cyclophosphamide and greater clinical experience than with sirolimus.
Cyclosporine — Randomized controlled trials and uncontrolled studies cited below have demonstrated the effectiveness of cyclosporine in reducing proteinuria in steroid-dependent and steroid-resistant FSGS [6,22,35-39]. The reported response rates in steroid-resistant disease range from 20 to 70 percent; however, efficacy in preventing progression to ESRD is unknown.
Thus, a trial of cyclosporine and low-dose prednisone is warranted in patients with steroid-dependent or steroid-resistant FSGS, particularly in those with marked or symptomatic nephrotic syndrome [40]. However, we avoid using cyclosporine or other calcineurin inhibitors in patients who have significant vascular or interstitial disease on renal biopsy or an estimated GFR <40 mL/min per 1.73 m2, given the potential nephrotoxicity of these drugs. (See "Cyclosporine and tacrolimus nephrotoxicity".)
The response to cyclosporine in FSGS occurs earlier (within three months) than the response to prednisone, although the rate of complete (versus partial) remission appears to be lower than with glucocorticoids [16,22,38].
Despite initial benefit, relapses are common after cessation of short-term therapy with cyclosporine, although long-term kidney function is preserved. The likelihood of relapse appears to be lower if cyclosporine treatment is prolonged, perhaps up to one year or longer after remission is induced, and then gradually tapered and discontinued [35]. However, the risk of cyclosporine nephrotoxicity with prolonged therapy, particularly if the dose is ≥5 mg/kg per day, must be weighed against potential benefits [35,38,40]. (See "Cyclosporine and tacrolimus nephrotoxicity".)
The following randomized trials illustrate the efficacy of cyclosporine among adults with steroid-resistant FSGS:
Based upon these observations, we treat with cyclosporine and concurrent low-dose prednisone as follows:
We monitor cyclosporine levels periodically to ascertain absorption and avoid higher, more nephrotoxic levels (ie, keep the level between 100 and 175 ng/mL) [33,39].
Tacrolimus — There is limited experience with tacrolimus for the treatment of FSGS [33,41-44]. The largest study was an open-label uncontrolled study consisting of 25 patients (mean proteinuria of 10.2 g/day and plasma creatinine concentration of 1.2 mg/dL [106 micromol/L]) [42]. The patients were resistant to or dependent upon cyclosporine and glucocorticoids and were given tacrolimus plus prednisone for six months. Seventeen patients had a reduction in proteinuria to <3 g/day and 12 had complete or partial remission. Thirteen relapsed after discontinuation of tacrolimus; reinstitution of therapy for one year resulted in complete and partial remission in five and four patients, respectively. Reversible mild acute nephrotoxicity occurred in 40 percent of patients and appeared to be associated with an inappropriately high starting dose.
In summary, tacrolimus may be of benefit in some patients with FSGS, but its efficacy compared to cyclosporine has not been evaluated. Studies in transplant recipients suggest that the efficacy and nephrotoxicity of the two drugs are similar. (See "Cyclosporine and tacrolimus nephrotoxicity".)
Mycophenolate mofetil — Observational studies [45-48] have suggested a benefit of mycophenolate mofetil (MMF) given with or without glucocorticoids in patients with FSGS [45-48].
One randomized trial has tested the efficacy of MMF and high dose dexamethasone [49]. The FSGS-Clinical trial (FSGS-CT) was an NIH-funded multicenter trial that compared mycophenolate mofetil plus oral pulse dexamethasone to cyclosporine among 138 patients with steroid-resistant primary FSGS [49]. Mycophenolate mofetil was given at 25 to 36 mg/kg per day; dexamethasone was given at 0.9 mg/kg per day for two consecutive days at the start of weeks 1 through 8, on alternating weeks through week 26 and every four weeks until week 50; and cyclosporine was given at 5 to 6 mg/kg per day with target trough levels of 100 to 250 ng/mL. All patients were given prednisone 0.3 mg/kg every other day for six months.
At a follow-up of 12 months, there was no difference between groups in the percentage of patients who achieved partial or complete remission (30 percent with MMF plus dexamethasone versus 45 percent with cyclosporine). There was also no difference in the percentage of patients who had a sustained remission at 26 weeks after the termination of treatment.However, this study has important limitations that hinder its interpretation [50]. First, the number of enrolled subjects was smaller than anticipated; whereas the trial was designed to include 500, only 138 patients were actually randomized. As a result, the trial may have been underpowered to detect small but clinically significant benefits associated with cyclosporine.
An additional limitation is that the inclusion criteria allowed patients to be defined as glucocorticoid-resistant after only four weeks of glucocorticoid therapy. This may have resulted in an overestimate of the benefit of immunosuppressive therapy since many patients (especially adults) respond to glucocorticoids after 8 to 12 weeks. The trial also included patients with non-nephrotic proteinuria who generally have a good prognosis and in practice would not be considered for immunosuppressive treatment. (See 'Degree of proteinuria' above and 'Initial immunosuppressive therapy' above.)
The permissive eligibility criteria (among the criteria for trial entry was protein excretion >1.0 grams/day as estimated by protein to creatinine ratio) may also have allowed the inclusion of patients with secondary FSGS. This is in contrast to most studies where patients labeled as having primary FSGS have nephrotic-range proteinuria and patients with presumed secondary FSGS have lower levels of protein excretion. The inclusion of patients with secondary FSGS could potentially have lowered the overall response rate that was observed in this trial since such patients generally do not respond to immunosuppressive treatment. (See "Classification and pathogenesis of focal segmental glomerulosclerosis", section on 'Distinguishing between primary and secondary FSGS'.)
In contrast to this underpowered randomized trial that demonstrated no benefit, some observational studies have suggested a possible benefit of MMF given with or without glucocorticoids:
Based upon these limited observations, we suggest that mycophenolate mofetil (750 to 1000 mg twice daily for six months) be used in patients with FSGS who are resistant to an adequate trial of prednisone and have not responded or should not be exposed to cyclosporine, or who have a partial response to prednisone and/or cyclosporine but have signs of steroid or cyclosporine toxicity.
Cytotoxic therapy — Data on the use of cytotoxic drugs for steroid-dependent or steroid-resistant FSGS in adults are limited to a few retrospective observational studies [10,16,33,39,41-43,45-48], and the previously described randomized trial comparing chlorambucil to cyclosporine, which showed no benefit with chlorambucil [39].
Cytotoxic therapy has been used primarily in the treatment of children with relapsing or steroid-dependent idiopathic nephrotic syndrome [51,52]. In these settings, cyclophosphamide (2 mg/kg per day for 8 to 12 weeks) induced complete or partial remission in approximately 75 percent of cases [6,51-53]. Cyclophosphamide was less effective in patients who were steroid-resistant, with less than 25 percent deriving sustained benefit from an 8- to 12-week course of therapy [6,52]. (See "Treatment of idiopathic nephrotic syndrome in children".)
We do not recommend cyclophosphamide in patients with primary FSGS who do not respond to an adequate trial of prednisone. However, cyclophosphamide may be considered in patients who have shown a partial response to prednisone (eg, ≥50 percent reduction in protein excretion) and who have extensive interstitial fibrosis and/or vascular disease on renal pathology and may therefore be at higher risk of calcineurin nephrotoxicity. If used, cyclophosphamide is added before the prednisone has been discontinued, and is administered for 8 to 12 weeks. More prolonged therapy (>12 weeks) is not beneficial [16,39]. Chlorambucil is not recommended because of greater toxicity.
Sirolimus — There are a few reports examining the use of sirolimus in patients with FSGS who had steroid-resistant disease or were intolerant to continuation of high dose steroids. An initial prospective study suggested benefit from sirolimus [54]. However, the use of sirolimus in the treatment of FSGS and other primary glomerulopathies may worsen renal function [55-57]. In one study of six patients with primary FSGS treated with sirolimus, five experienced a significant decline in GFR after seven to nine months of therapy, and none had a remission of proteinuria [55]. An additional concern is that sirolimus has been associated with the development of proteinuria and FSGS in renal transplant recipients, as well as acute renal failure when used in combination with calcineurin inhibitors. (See "Mammalian target of rapamycin (mTOR) inhibitors in renal transplantation".)
We do not advocate the use of sirolimus in the treatment of primary FSGS.
Plasmapheresis and related modalities — There may be a limited role for plasmapheresis in the treatment of primary FSGS, based in part upon studies in patients who have recurrent FSGS in the renal allograft [34,40,58-60]. In the latter setting, removal of a circulating factor by plasmapheresis or a protein adsorption column can dramatically reduce proteinuria and, in some cases, induce complete remission. (See "Focal segmental glomerulosclerosis: Recurrence after transplantation".)
Any benefit in transplant recipients is generally transient, as protein excretion often returns to pretreatment levels within two months. Furthermore, the applicability of data from transplant recipients to patients with primary FSGS is unclear.
There are conflicting reports regarding benefits of plasmapheresis in treating primary FSGS. In one uncontrolled study of patients with refractory primary FSGS, the addition of plasmapheresis seemed beneficial in some individuals [59]. Eleven patients with biopsy proven FSGS unresponsive to glucocorticoids and cytotoxic therapy underwent an average of 17 plasmapheresis sessions over approximately 22 weeks. At follow-up at 27 months, a complete or partial response was observed in six and two patients, respectively. Among the complete responders, average proteinuria fell from 5.8 to 0.9 g/day and the plasma creatinine stabilized.
In contrast, a second uncontrolled study reported a relatively poor response rate with plasmapheresis, with only two of eight patients experiencing transient improvement in proteinuria [60]. The ongoing immunosuppressive therapy in the first study, compared to no consistent post-plasmapheresis immunosuppression in the second study, may explain these widely discrepant findings.
Whether a patient with primary FSGS might respond to plasmapheresis is thought to vary with the presence or absence, and the absolute level, of the circulating permeability factor. The presence of a permeability factor can be assessed via an in-vitro examination, referred to as the GVV-test [61]. In this test, the patient's serum is incubated with isolated rat glomeruli in a hypo-oncotic solution. If albumin leakage is increased because of the presence of a permeability factor, the volume of the rat glomeruli is reduced due to concurrent water transfer.
In one report, two patients with a positive GVV-test responded to plasma immunoadsorption [62]; after therapy, no evidence of a circulating permeability factor was found in either individual. However, when measured serially in another study, the levels of the permeability factor in patients with primary FSGS were lower than previously reported for patients with recurrent post-transplant FSGS, were not related to severity of disease, and did not decrease despite clinical response to cyclosporine [63].
The accurate assessment of the role of plasmapheresis and the GVV-test in the management of patients with FSGS requires further evaluation. This test is not routinely used for diagnostic purposes in patients with primary FSGS.
Based upon very limited experience, we only consider plasmapheresis in the following settings:
Plasmapheresis should be performed in conjunction with immunosuppression. (See "Prescription and technique of therapeutic plasma exchange".)
The decision to treat patients with significantly reduced renal function (eg, GFR <25 to 35 mL/min per 1.73 m2) should take into consideration the acuity of the renal failure, findings on renal biopsy (eg, presence of significant tubulointerstitial fibrosis and glomerulosclerosis), and the individual patient's risk for adverse consequences related to therapy.
LDL apheresis — Several small nonrandomized studies using variable schedules of LDL apheresis in patients with steroid-resistant primary FSGS have demonstrated some benefit in terms of reduction in proteinuria and improvement in serum albumin concentration, at least in short term follow-up [64-68]. Why this might work is unclear, but postulated mechanisms include reduction in oxidized LDL and associated inflammatory cytokines, and improvement in hypercoagulability.
Nonimmunosuppressive therapy — Two major nonimmunosuppressive therapies that should be instituted in most patients with primary FSGS are angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), and lipid-lowering with a statin. These are also the mainstays of therapy for nonnephrotic patients with primary FSGS and for patients with proteinuric chronic kidney disease in general.
Nonsteroidal antiinflammatory drugs (NSAIDs) also may reduce proteinuria, but they are rarely used given their potential to reduce kidney function.
ACE inhibitors or ARBs — An ACE inhibitor or an ARB should be given to all patients with primary FSGS, even as specific immunosuppressive treatment is undertaken, or as primary therapy for patients with nonnephrotic proteinuria and patients who have other reasons for not receiving immunosuppression.
ACE inhibitors reduce proteinuria in patients with both primary and secondary FSGS and rarely induce a remission without immunosuppressive treatment [9,69-73]. In addition, these drugs slow the rate of progression to kidney failure in patients with proteinuric renal diseases, although such a benefit has not been specifically proven in primary FSGS. (See "Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults".)
For these reasons, administration of an ACE inhibitor or ARB is recommended for virtually all patients with primary FSGS, in particular for those who do not go promptly into remission with immunosuppressive therapy. Specific goals should be met as described elsewhere. (See "Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults".)
Lipid-lowering — Hyperlipidemia, with often dramatic elevations in the serum cholesterol concentration, is commonly present in patients with nephrotic syndrome. (See "Lipid abnormalities in nephrotic syndrome".)
The following observations provide the rationale for lipid-lowering therapy with a statin in such patients:
Thus, patients with FSGS who have persistent nephrotic syndrome and/or chronic kidney disease should be treated with a statin. Patients also on cyclosporine are at increased risk for rhabdomyolysis because of a drug interaction with many statins. (See "Lipid abnormalities in nephrotic syndrome" and "Muscle injury associated with lipid lowering drugs".)
NSAIDs — Among patients who do not respond to immunosuppressive therapy, as many as 60 percent given an NSAID have a marked reduction in proteinuria (50 to 75 percent) that presumably reflects a decline in intraglomerular pressure induced by renal vasoconstriction [8,74]. Uncontrolled observations suggest that these responders have a lower rate of progressive renal failure, although the true efficacy of these agents remains to be proven [74].
The possibility of precipitating acute renal failure, a known complication of traditional NSAIDs and the newer selective COX-2 inhibitors, has generally precluded use of these drugs for reducing proteinuria and slowing progression of renal insufficiency. (See "NSAIDs: Acute kidney injury (acute renal failure) and nephrotic syndrome".)
The only circumstance in which we consider NSAIDs in primary FSGS is in patients with massive proteinuria and end-stage renal disease in an attempt to induce medical nephrectomy.
Other agents — Limited evidence suggests that an orally active antifibrotic agent, pirfenidone, may slow the rate of progression in patients with FSGS. In an open-label trial of 21 patients with biopsy-proven FSGS and advanced chronic kidney disease, the rate of decline in kidney function over one year with pirfenidone was compared with that observed with conventional ACE inhibitor and ARB therapy over an equivalent time period [75]. Pirfenidone improved the monthly change in GFR from -.61 mL/min per 1.73 m2 to -.45 mL/min per 1.73 m2 and had no effect on either proteinuria or blood pressure. The drug was well tolerated. Further study in controlled trials is required to clarify the role of this agent.
The thiazolidinedione rosiglitazone has also been shown to have antifibrotic effects in animal models of FSGS [76]. A phase 1 clinical trial (FONT-I) showed that this agent was safe and well tolerated in 11 patients with biopsy-proven FSGS [77]. Additional studies are in progress (FONT-II).
Role of protein restriction — The role of a protein-restricted diet in nephrotic syndrome and in chronic kidney disease is discussed elsewhere. (See "Protein restriction and progression of chronic kidney disease".)
Complications of therapy — The toxicities of the immunosuppressive drugs used to treat primary FSGS are described in detail elsewhere.
SUMMARY AND RECOMMENDATIONS — Focal segmental glomerulosclerosis (FSGS) may occur either as a primary disease or as a secondary response to glomerular injury. Distinguishing between primary and secondary disease is important because immunosuppressive therapy is indicated in most patients with primary FSGS but not in secondary FSGS. (See 'Treatment' above and "Classification and pathogenesis of focal segmental glomerulosclerosis".)
Untreated patients with nephrotic syndrome (proteinuria >3.5 g/day and hypoalbuminemia) due to primary FSGS typically have a progressive course to ESRD. Treatment with glucocorticoids and other immunosuppressive agents can lead to partial and complete proteinuric response rates of almost 70 percent. Patients without nephrotic syndrome are more likely to remit spontaneously, or to have more slowly progressive disease. (See 'Prognosis' above.)
The most important predictor of outcome in patients with primary FSGS is the response to initial therapy.
Over the long-term, there is a much lower rate of renal failure among patients achieving a complete or partial remission, compared with those who are steroid-resistant. Patients with complete remission should not progress to renal failure if they do not relapse. (See 'Response to therapy' above and 'Disease progression' above.)
The therapeutic recommendations that follow do not apply to collapsing FSGS and to secondary FSGS, which are discussed separately. (See "Collapsing focal segmental glomerulosclerosis and other renal diseases associated with HIV infection" and "Collapsing focal segmental glomerulosclerosis not associated with HIV infection" and "Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults".)
Initial immunosuppression — We recommend immunosuppressive therapy for nephrotic patients with primary FSGS (Grade 1A). The decision to provide immunosuppression to patients with significantly decreased kidney function (eg, GFR <25 to 35 mL/min per 1.73 m2) should take into consideration the acuity of the renal failure (suggesting more reversible disease), findings on renal biopsy (eg, presence of significant tubulointerstitial fibrosis and glomerulosclerosis, which suggest less reversible disease), and the individual patient's risk for adverse consequences related to immunosuppression.
Relapsing disease — A relapse is defined as a return of proteinuria to ≥3.5 g/day in someone who had undergone a complete or partial remission.
If a patient has recurrence of nephrotic syndrome after a complete response to steroids and has not had significant side effects related to this therapy, we suggest a second course of prednisone (Grade 2C). (See 'Initial immunosuppressive therapy' above.)
If the patient has had significant steroid-induced toxicity or has subsequent relapses, we suggest treatment with cyclosporine and low dose prednisone (Grade 2B). The same considerations for its use in initial therapy regarding cautions, dose, and duration of therapy apply.
Steroid-resistant or steroid-dependent disease — We recommend cyclosporine for the treatment of patients who are resistant to or dependent upon glucocorticoids (Grade 1B). The same considerations for its use in initial therapy regarding cautions, dose, and duration of therapy apply. (See 'Initial immunosuppressive therapy' above and 'Cyclosporine' above.)
We suggest treating with mycophenolate mofetil in patients who are resistant to or dependent upon prednisone and have not responded or should not be exposed to cyclosporine, or in patients who have shown a partial response to prednisone and/or cyclosporine but have signs of steroid or cyclosporine toxicity (Grade 2C). We usually treat with 750 to 1000 mg twice daily for six months. (See 'Mycophenolate mofetil' above.)
We suggest plasmapheresis in combination with immunosuppression only in the rare circumstances described above (Grade 2C). (See 'Plasmapheresis and related modalities' above.)
Monitoring — We recommend obtaining routine blood chemistries, including a plasma creatinine concentration for estimation of GFR, and measurement of the urine protein-to-creatinine ratio at two- to four-week intervals during the initial two to three months of therapy. Prior to tapering immunosuppression, we confirm the level of proteinuria with a 24-hour urine collection. Once drug therapy is stabilized and/or is being tapered, we suggest monitoring at one- to two-month intervals. (See 'Monitoring response to and duration of therapy' above.)
Nonimmunosuppressive therapies — For all patients with FSGS, we recommend treatment with an ACE inhibitor or an ARB (Grade 1B). ACE inhibitors or ARBs are the principal therapy for nonnephrotic patients and patients not eligible for immunosuppression, and may also be particularly beneficial for nephrotic patients who do not go into a prompt remission following immunosuppressive therapy or who have persistently decreased kidney function. (See "Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults".)
For patients with persistent nephrotic syndrome and/or chronic kidney disease, we suggest lipid lowering with a statin, with the goal of reducing the risk of cardiovascular disease (Grade 2B). Patients treated with cyclosporine and a statin should be monitored for rhabdomyolysis. (See "Lipid abnormalities in nephrotic syndrome" and "Treatment of lipids (including hypercholesterolemia) in secondary prevention" and "Muscle injury associated with lipid lowering drugs".)
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