Serious infections in patients with relapsing and progressive forms of multiple sclerosis: A German claims data study

Narrative Review on the Use of Cladribine Tablets as Exit Therapy for Stable Elderly Patients with Multiple Sclerosis

The number of ageing people with relapsing multiple sclerosis (RMS) is increasing. The efficacy of disease-modifying therapies (DMTs) for RMS declines with age. Also, older persons with MS may be more susceptible to infections, hospitalisations and malignancy. Aging people with MS have higher rates of comorbidities versus aged-matched controls, increasing the individual risk of disability. We review the therapeutic properties of cladribine tablets (CladT) in ageing people with RMS, with regard to their utility for allowing these individuals to cease continuous administration of a DMT (i.e. to act as an "exit therapy"). CladT is thought to be an immune reconstitution therapy, in that two short courses of oral treatment 1 year apart provide suppression of MS disease activity in responders that far outlasts the duration of treatment and post-treatment reductions in lymphocyte counts. Post hoc analyses, long-term follow-up of populations with RMS in randomised trials, and real-world evidence suggest that the efficacy of CladT is probably independent of age, although more data in the elderly are still needed. No clear adverse signals for lymphopenia or other adverse safety signals have emerged with increasing age, although immunosenescence in the setting of age-related "inflammaging" may predispose elderly patients to a higher risk of infections. Updating vaccination status is recommended, especially against pneumococci and herpes zoster for older patients, to minimise the risk of these infections. CladT may be a useful alternative treatment for ageing people with MS who often bear a burden of multiple comorbidities and polypharmacy and who are more exposed to the adverse effects of continuous immunosuppressive therapy.

Hypogammaglobulinemia and Infection Risk in an Ocrelizumab-treated Multiple Sclerosis Cohort

BACKGROUND

Ocrelizumab is an effective anti-CD20 therapy approved for Relapsing Remitting (RRMS) and Primary Progressive Multiple Sclerosis (PPMS). In clinical trials, a proportion of patients developed hypogammaglobulinemia which could contribute to infection risk. This study aimed to identify hypogammaglobulinemia and its risk factors and evaluate potentially associated serious infection risk in a real-world cohort of patients.

METHODS

All MS patients treated with ocrelizumab in a Quebec City MS clinic from January 2017 to August 2021 were included and detailed patient characteristics were collected by chart review. Levels of immunoglobulins (IgM, IgA and IgG) were assessed prior to each treatment. Serious infection was defined as an infection requiring hospitalization or emergency room treatment. Association between hypogammaglobulinemia and serious infection was analyzed.

RESULTS

A total of 266 patients (average follow-up 2.05 years) were included (87% RRMS). After 6 infusions, 32.8%, 3.5% and 4.2% of patients had at least one IgM, IgA and IgG hypogammaglobulinemia event respectively. Aside from pre-treatment hypogammaglobulinemia, there were no variables associated with on-treatment hypogammaglobulinemia. There was a total of 21 serious infections (3.36 and 12.33 per 100-person-years in RRMS and PPMS). Developing hypogammaglobulinemia during treatment was not associated with serious infection. A regression analysis did not show associations between serious infection and key disease characteristics.

CONCLUSION

Similar to ocrelizumab extension studies, our cohort demonstrated a significant rate of hypogammaglobulinemia over time, mostly with IgM. No association was found between hypogammaglobulinemia and serious infection.

Claims-based algorithm to estimate the Expanded Disability Status Scale for multiple sclerosis in a German health insurance fund: a validation study using patient medical records

Background

The Expanded Disability Status Scale (EDSS) quantifies disability and measures disease progression in multiple sclerosis (MS), however is not available in administrative claims databases.

Objectives

To develop a claims-based algorithm for deriving EDSS and validate it against a clinical dataset capturing true EDSS values from medical records.

Methods

We built a unique linked dataset combining claims data from the German AOK PLUS sickness fund and medical records from the Multiple Sclerosis Management System 3D (MSDS3D). Data were deterministically linked based on insurance numbers. We used 69 MS-related diagnostic indicators recorded with ICD-10-GM codes within 3 months before and after recorded true EDSS measures to estimate a claims-based EDSS proxy (pEDSS). Predictive performance of the pEDSS was assessed as an eight-fold (EDSS 1.0-7.0, ≥8.0), three-fold (EDSS 1.0-3.0, 4.0-5.0, ≥6.0), and binary classifier (EDSS <6.0, ≥6.0). For each classifier, predictive performance measures were determined, and overall performance was summarized using a macro F1-score. Finally, we implemented the algorithm to determine pEDSS among an overall cohort of patients with MS in AOK PLUS, who were alive and insured 12 months prior to and after index diagnosis.

Results

We recruited 100 people with MS insured by AOK PLUS who had ≥1 EDSS measure in MSDS3D between 01/10/2015 and 30/06/2019 (620 measurements overall). Patients had a mean rescaled EDSS of 3.2 and pEDSS of 3.0. The pEDSS deviated from the true EDSS by 1.2 points, resulting in a mean squared error of prediction of 2.6. For the eight-fold classifier, the macro F1-score of 0.25 indicated low overall predictive performance. Broader severity groupings were better performing, with the three-fold and binary classifiers for severe disability achieving a F1-score of 0.68 and 0.84, respectively. In the overall AOK PLUS cohort (3,756 patients, 71.9% female, mean 51.9 years), older patients, patients with progressive forms of MS and those with higher comorbidity burden showed higher pEDSS.

Conclusion

Generally, EDSS was underestimated by the algorithm as mild-to-moderate symptoms were poorly captured in claims across all functional systems. While the proxy-based approach using claims data may not allow for granular description of MS disability, broader severity groupings show good predictive performance.

Interplay between age and disease-modifying treatments in influencing infection risk in multiple sclerosis

BACKGROUND

Disease-modifying treatments (DMTs) can increase the risk of infections in multiple sclerosis (MS). Aged individuals are usually excluded from clinical trials, and there is uncertainty regarding safety of immunosuppressive DMTs in these patients.

OBJECTIVE

To investigate the association of DMTs, ageing and other clinical variables with risk of infections in MS patients.

METHODS

Prospective single-centre observational study collecting information on occurrence, type and grade of infections in patients followed at the MS centre, Lugano (Switzerland). Associations with infection risk were tested using multivariable Poisson and Cox regressions.

RESULTS

A total of 503 patients were included (injectables/untreated, n = 127; orals, n = 139; monoclonal antibodies (MAB), n = 237) and 326 infections recorded over 12.6 (11.6-14.0) months. As compared to injectable DMTs/no treatment, MAB and oral DMTs were positively associated with infection incidence (IRR = 2.32, 95% confidence interval (CI) = 1.39-3.89, p = 0.001; IRR = 2.04, 95% CI = 1.19-3.49, p = 0.009, respectively). After excluding COVID-19, the effect of MAB was stronger among patients <50 years (IRR = 5.90, 95% CI = 2.80-12.45, p < 0.001) than >50 years (IRR = 1.95, 95% CI = 0.91-4.15, p = 0.084). Higher disability and male sex were the only variables associated with severe infections.

CONCLUSION

Treatment with MAB and oral DMTs is associated with higher incidence of infections, with a stronger effect in young MS patients. Disability appears the main predictor of severe infections regardless of treatment.

Comparing the risk of serious infections in patients with and without MS: A German claims data analysis

BACKGROUND

Research suggests that serious infections (SIs), comorbidities, and advanced disability represent key drivers of early death in people with Multiple Sclerosis (pwMS). Nevertheless, further research is warranted to better characterize and quantify the risk of SI among pwMS compared to the general population.

METHODS

Our study consisted of a retrospective analysis of claims data provided by a German statutory health insurance fund, AOK PLUS, covering 3.4 million individuals in Saxony and Thuringia from 01/01/2015-31/12/2019. A propensity score (PS) matching method was used to compare the incidence of SIs among people with and without MS. PwMS were required to have ≥1 inpatient or ≥2 confirmed outpatient diagnoses of MS (ICD-10 G35) from a neurologist from 01/01/2016-31/12/2018, while people from the general population could not have any inpatient/outpatient codes for MS during the entire study period. The index date was defined as the first observed MS diagnosis or, in the case of the non-MS cohort, a randomly assigned date within the inclusion period. For both cohorts a PS was assigned, corresponding with their probabilistic likelihood of having MS based on observable factors including patient characteristics, comorbidities, medication use and other variables. People with and without MS were matched using a 1:1 nearest neighbor strategy. An exhaustive list of ICD-10 codes was created in association with 11 main SI categories. SIs were those recorded as the main diagnosis during an inpatient stay. ICD-10 codes from the 11 main categories were sorted into smaller classification units, used to distinguish between infections. A 60-day threshold for measuring new cases was defined to account for the potential risk of re-infection. Patients were observed until the end of the study period (31/12/2019) or death. Cumulative incidence, incidence rates (IRs) and IR ratios (IRRs) were reported during follow-up and at 1-, 2- and 3-years post-index.

RESULTS

A total of 4250 and 2,098,626 patients were included in the unmatched cohorts of people with and without MS. Ultimately, one match was identified for all 4,250 pwMS, corresponding with a final population of 8,500 patients. On average, patients were 52.0/52.2 years in the matched MS/non-MS cohorts; the gender breakdown was 72% female. Overall, IRs of SIs per 100 patient years (PY) were higher in pwMS than in those without MS (1 year: 7.6 vs. 4.3; 2 years: 7.1 vs. 3.8; 3 years: 6.9 vs. 3.9). During follow-up, the most common infection types in pwMS were of a bacterial/parasitic origin (2.3 per 100 PY), followed by respiratory (2.0) and genitourinary (1.9) infections. Respiratory infections were most common in patients without MS (1.5 per 100 PY). Differences in the IRs of SIs were statistically significant (p<0.01) at each measurement window, with IRRs ranging from 1.7-1.9. PwMS had a higher risk of hospitalized genitourinary infections (IRR: 3.3-3.8) and bacterial/parasitic infections (2.0-2.3).

CONCLUSIONS

The incidence of SIs is much higher in pwMS, than comparators from the general population in Germany. Differences in hospitalized infection rates were largely driven by higher levels of bacterial/parasitic and genitourinary infections in the MS population.