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STOCKHOLM – Christopher McGuigan, MD, and colleagues reported at the annual congress of the European Committee for Treatment and Research in Multiple Sclerosis.
“This is a very important issue for us as neurologists. I think this data suggests that plasma exchange does not seem to confer an advantage to our patients when it comes to mortality and – albeit with caveats – it actually seems to be associated with worsening of the disability level in survivors,” according to Dr. McGuigan, consultant neurologist at St. Vincent’s University Hospital in Dublin and clinical professor at University College Dublin.
Natalizumab is an effective treatment for patients with highly active MS, but its use is limited by the feared complication of PML. Plasma exchange to clear the drug from the patient’s system is a popular and biologically plausible therapy, but its impact on clinical outcomes had not been formally studied until now.
Examining a database of confirmed PML cases
Dr. McGuigan presented a retrospective study of 723 patients with confirmed PML included in the natalizumab pharmacovigilance database run by Biogen, which markets the drug. A total of 85% (616 patients) underwent plasma exchange. The study’s primary outcome was the survival rate 2 years after PML diagnosis in patients who received plasma exchange, compared with those who did not.
Since the viral load of John Cunningham (JC) virus is known to influence outcome in PML, Dr. McGuigan and coinvestigators stratified the primary outcome based on tertiles of baseline viral copy number (VCN). The key study finding was that, across the range of viral loads, plasma exchange was consistently associated with a numerically worse 2-year survival rate, although the difference did not reach statistical significance. Among patients with less than a log5 baseline JC virus VCN, 2-year survival was 88.2% in the plasma exchange group, compared with 89.3% in the patients who did not undergo plasma exchange. For patients with a JC virus VCN greater than log5 but not more than log7, the survival rate was 89.3% without plasma exchange versus 73.8% with the intervention. In the group with greater than a log7 VCN, the 2-year survival was 78.9% without plasma exchange and 68.2% with it.
Statistically significant covariates
In a multivariate Cox proportional hazards analysis, plasma exchange was associated with a statistically nonsignificant 44% increased risk of mortality at 2 years post PML diagnosis. However, several other covariates emerged as statistically significant independent predictors of 2-year mortality. These included age greater than 50 years at diagnosis of PML, with an associated hazard ratio of 1.56, compared with younger patients; male gender (HR, 1.48); a JC virus VCN greater than log 7, compared with log 5 or less (HR, 2.86); a VCN greater than log5 but not more than log7, compared with a VCN of log5 or less (HR, 2.11); and widespread as opposed to localized MRI brain lesions of PML (HR, 1.61). In contrast, an asymptomatic presentation of PML was protective, with an HR of 0.38, compared with patients with a symptomatic presentation.
The likelihood of survival at 2 years was not affected by the number of plasma exchange cycles utilized, the number of natalizumab infusions received prior to diagnosis of PML, or the time from the last natalizumab infusion to starting plasma exchange.
Additional analyses focused on functional ability and disability
A secondary analysis addressed the question of whether plasma exchange has a favorable impact on functional ability. This is an important issue because many MS patients who remain alive 2 years after diagnosis of PML are left with marked permanent disability. This analysis was restricted to the 523 MS patients with PML for whom Expanded Disability Status Scale (EDSS) scores were available 6 months or more after PML diagnosis. The key finding here was that, at 2 years, 62% of the plasma exchange group, but only 38% of non–plasma exchange controls, were either dead or had an EDSS score of 7 or greater, which is a degree of disability likely to render a patient unable to live independently.
Of note, the median EDSS score 6 months before diagnosis of PML was 3.5 in both groups. Moreover, the median EDSS score at the time of diagnosis was similar in the two groups as well: 4.0 in those who underwent plasma exchange and 4.5 in those who did not. So the physician decision to employ plasma exchange clearly was not driven by more-severe disability.
In a multivariate analysis, plasma exchange was independently associated with a 168% increased likelihood of death or an EDSS score of 7 or more at 2 years. A sensitivity analysis restricted to patients who fell into that category was supportive of the main analysis: it concluded that such patients were 159% more likely to have received plasma exchange than not.
Dr. McGuigan cited several study limitations, including possible selection bias, inability to assess the potential impact of other disease-modifying therapies utilized after PML diagnosis, the lack of baseline EDSS scores in a fair number of patients, and the necessity to evaluate all-cause mortality rather than death attributable to PML.
He made a plea for neurologists to diligently submit their own cases of natalizumab-associated PML in MS patients to the Biogen pharmacovigilance database, which is totally dependent upon voluntary physician reporting.
“This is the only tool by which we can get this information at present. It’s the best data we’re likely to be able to get,” he observed.
The study was funded by Biogen. Dr. McGuigan reported receiving research grants from and serving as an advisor to that company and several other pharmaceutical companies.
SOURCE: McGuigan C et al. ECTRIMS 2019, Abstract 63.
STOCKHOLM – Christopher McGuigan, MD, and colleagues reported at the annual congress of the European Committee for Treatment and Research in Multiple Sclerosis.
“This is a very important issue for us as neurologists. I think this data suggests that plasma exchange does not seem to confer an advantage to our patients when it comes to mortality and – albeit with caveats – it actually seems to be associated with worsening of the disability level in survivors,” according to Dr. McGuigan, consultant neurologist at St. Vincent’s University Hospital in Dublin and clinical professor at University College Dublin.
Natalizumab is an effective treatment for patients with highly active MS, but its use is limited by the feared complication of PML. Plasma exchange to clear the drug from the patient’s system is a popular and biologically plausible therapy, but its impact on clinical outcomes had not been formally studied until now.
Examining a database of confirmed PML cases
Dr. McGuigan presented a retrospective study of 723 patients with confirmed PML included in the natalizumab pharmacovigilance database run by Biogen, which markets the drug. A total of 85% (616 patients) underwent plasma exchange. The study’s primary outcome was the survival rate 2 years after PML diagnosis in patients who received plasma exchange, compared with those who did not.
Since the viral load of John Cunningham (JC) virus is known to influence outcome in PML, Dr. McGuigan and coinvestigators stratified the primary outcome based on tertiles of baseline viral copy number (VCN). The key study finding was that, across the range of viral loads, plasma exchange was consistently associated with a numerically worse 2-year survival rate, although the difference did not reach statistical significance. Among patients with less than a log5 baseline JC virus VCN, 2-year survival was 88.2% in the plasma exchange group, compared with 89.3% in the patients who did not undergo plasma exchange. For patients with a JC virus VCN greater than log5 but not more than log7, the survival rate was 89.3% without plasma exchange versus 73.8% with the intervention. In the group with greater than a log7 VCN, the 2-year survival was 78.9% without plasma exchange and 68.2% with it.
Statistically significant covariates
In a multivariate Cox proportional hazards analysis, plasma exchange was associated with a statistically nonsignificant 44% increased risk of mortality at 2 years post PML diagnosis. However, several other covariates emerged as statistically significant independent predictors of 2-year mortality. These included age greater than 50 years at diagnosis of PML, with an associated hazard ratio of 1.56, compared with younger patients; male gender (HR, 1.48); a JC virus VCN greater than log 7, compared with log 5 or less (HR, 2.86); a VCN greater than log5 but not more than log7, compared with a VCN of log5 or less (HR, 2.11); and widespread as opposed to localized MRI brain lesions of PML (HR, 1.61). In contrast, an asymptomatic presentation of PML was protective, with an HR of 0.38, compared with patients with a symptomatic presentation.
The likelihood of survival at 2 years was not affected by the number of plasma exchange cycles utilized, the number of natalizumab infusions received prior to diagnosis of PML, or the time from the last natalizumab infusion to starting plasma exchange.
Additional analyses focused on functional ability and disability
A secondary analysis addressed the question of whether plasma exchange has a favorable impact on functional ability. This is an important issue because many MS patients who remain alive 2 years after diagnosis of PML are left with marked permanent disability. This analysis was restricted to the 523 MS patients with PML for whom Expanded Disability Status Scale (EDSS) scores were available 6 months or more after PML diagnosis. The key finding here was that, at 2 years, 62% of the plasma exchange group, but only 38% of non–plasma exchange controls, were either dead or had an EDSS score of 7 or greater, which is a degree of disability likely to render a patient unable to live independently.
Of note, the median EDSS score 6 months before diagnosis of PML was 3.5 in both groups. Moreover, the median EDSS score at the time of diagnosis was similar in the two groups as well: 4.0 in those who underwent plasma exchange and 4.5 in those who did not. So the physician decision to employ plasma exchange clearly was not driven by more-severe disability.
In a multivariate analysis, plasma exchange was independently associated with a 168% increased likelihood of death or an EDSS score of 7 or more at 2 years. A sensitivity analysis restricted to patients who fell into that category was supportive of the main analysis: it concluded that such patients were 159% more likely to have received plasma exchange than not.
Dr. McGuigan cited several study limitations, including possible selection bias, inability to assess the potential impact of other disease-modifying therapies utilized after PML diagnosis, the lack of baseline EDSS scores in a fair number of patients, and the necessity to evaluate all-cause mortality rather than death attributable to PML.
He made a plea for neurologists to diligently submit their own cases of natalizumab-associated PML in MS patients to the Biogen pharmacovigilance database, which is totally dependent upon voluntary physician reporting.
“This is the only tool by which we can get this information at present. It’s the best data we’re likely to be able to get,” he observed.
The study was funded by Biogen. Dr. McGuigan reported receiving research grants from and serving as an advisor to that company and several other pharmaceutical companies.
SOURCE: McGuigan C et al. ECTRIMS 2019, Abstract 63.
STOCKHOLM – Christopher McGuigan, MD, and colleagues reported at the annual congress of the European Committee for Treatment and Research in Multiple Sclerosis.
“This is a very important issue for us as neurologists. I think this data suggests that plasma exchange does not seem to confer an advantage to our patients when it comes to mortality and – albeit with caveats – it actually seems to be associated with worsening of the disability level in survivors,” according to Dr. McGuigan, consultant neurologist at St. Vincent’s University Hospital in Dublin and clinical professor at University College Dublin.
Natalizumab is an effective treatment for patients with highly active MS, but its use is limited by the feared complication of PML. Plasma exchange to clear the drug from the patient’s system is a popular and biologically plausible therapy, but its impact on clinical outcomes had not been formally studied until now.
Examining a database of confirmed PML cases
Dr. McGuigan presented a retrospective study of 723 patients with confirmed PML included in the natalizumab pharmacovigilance database run by Biogen, which markets the drug. A total of 85% (616 patients) underwent plasma exchange. The study’s primary outcome was the survival rate 2 years after PML diagnosis in patients who received plasma exchange, compared with those who did not.
Since the viral load of John Cunningham (JC) virus is known to influence outcome in PML, Dr. McGuigan and coinvestigators stratified the primary outcome based on tertiles of baseline viral copy number (VCN). The key study finding was that, across the range of viral loads, plasma exchange was consistently associated with a numerically worse 2-year survival rate, although the difference did not reach statistical significance. Among patients with less than a log5 baseline JC virus VCN, 2-year survival was 88.2% in the plasma exchange group, compared with 89.3% in the patients who did not undergo plasma exchange. For patients with a JC virus VCN greater than log5 but not more than log7, the survival rate was 89.3% without plasma exchange versus 73.8% with the intervention. In the group with greater than a log7 VCN, the 2-year survival was 78.9% without plasma exchange and 68.2% with it.
Statistically significant covariates
In a multivariate Cox proportional hazards analysis, plasma exchange was associated with a statistically nonsignificant 44% increased risk of mortality at 2 years post PML diagnosis. However, several other covariates emerged as statistically significant independent predictors of 2-year mortality. These included age greater than 50 years at diagnosis of PML, with an associated hazard ratio of 1.56, compared with younger patients; male gender (HR, 1.48); a JC virus VCN greater than log 7, compared with log 5 or less (HR, 2.86); a VCN greater than log5 but not more than log7, compared with a VCN of log5 or less (HR, 2.11); and widespread as opposed to localized MRI brain lesions of PML (HR, 1.61). In contrast, an asymptomatic presentation of PML was protective, with an HR of 0.38, compared with patients with a symptomatic presentation.
The likelihood of survival at 2 years was not affected by the number of plasma exchange cycles utilized, the number of natalizumab infusions received prior to diagnosis of PML, or the time from the last natalizumab infusion to starting plasma exchange.
Additional analyses focused on functional ability and disability
A secondary analysis addressed the question of whether plasma exchange has a favorable impact on functional ability. This is an important issue because many MS patients who remain alive 2 years after diagnosis of PML are left with marked permanent disability. This analysis was restricted to the 523 MS patients with PML for whom Expanded Disability Status Scale (EDSS) scores were available 6 months or more after PML diagnosis. The key finding here was that, at 2 years, 62% of the plasma exchange group, but only 38% of non–plasma exchange controls, were either dead or had an EDSS score of 7 or greater, which is a degree of disability likely to render a patient unable to live independently.
Of note, the median EDSS score 6 months before diagnosis of PML was 3.5 in both groups. Moreover, the median EDSS score at the time of diagnosis was similar in the two groups as well: 4.0 in those who underwent plasma exchange and 4.5 in those who did not. So the physician decision to employ plasma exchange clearly was not driven by more-severe disability.
In a multivariate analysis, plasma exchange was independently associated with a 168% increased likelihood of death or an EDSS score of 7 or more at 2 years. A sensitivity analysis restricted to patients who fell into that category was supportive of the main analysis: it concluded that such patients were 159% more likely to have received plasma exchange than not.
Dr. McGuigan cited several study limitations, including possible selection bias, inability to assess the potential impact of other disease-modifying therapies utilized after PML diagnosis, the lack of baseline EDSS scores in a fair number of patients, and the necessity to evaluate all-cause mortality rather than death attributable to PML.
He made a plea for neurologists to diligently submit their own cases of natalizumab-associated PML in MS patients to the Biogen pharmacovigilance database, which is totally dependent upon voluntary physician reporting.
“This is the only tool by which we can get this information at present. It’s the best data we’re likely to be able to get,” he observed.
The study was funded by Biogen. Dr. McGuigan reported receiving research grants from and serving as an advisor to that company and several other pharmaceutical companies.
SOURCE: McGuigan C et al. ECTRIMS 2019, Abstract 63.
REPORTING FROM ECTRIMS 2019
Key clinical point: Plasma exchange has no clinical benefit in natalizumab-associated progressive multifocal leukoencephalopathy (PML).
Major finding: The risk of composite endpoint of death or an Expanded Disability Status Scale of 7.0 or more at follow-up 2 years after a natalizumab-associated PML diagnosis was an adjusted 168% greater in multiple sclerosis patients who underwent plasma exchange than in those who did not.
Study details: A retrospective analysis of the records of 723 multiple sclerosis patients with confirmed natalizumab-associated PML.
Disclosures: The study was funded by Biogen. The presenter reported receiving research grants from and serving as an advisor to Biogen and several other pharmaceutical companies.
Source: McGuigan C et al. ECTRIMS 2019, Abstract 63.