Background/Purpose:

Interstitial lung disease (ILD) is a fatal complication of connective tissue diseases (CTDs). Despite numerous advances in immunosuppressive agents, data on effective treatment for this challenging entity is limited. This study aims to evaluate the efficacy of rituximab (RTX) in patients with CTD-ILD and determine factors correlated with outcomes at 6, 12 and 24 months post-RTX.

Methods:

We studied 47 patients with CTD-ILD, who met ACR classification criteria for a specific CTD. ILD was confirmed by high-resolution CT chest (HRCT) and pulmonary function tests with forced vital capacity (FVC) and diffusion capacity of lung for carbon monoxide (DLCO). We compared HRCT chest findings, %FVC and %DLCO at time of diagnosis and at 6, 12 and 24 months post-RTX. At diagnosis HRCT chest findings classified into 3 groups (mild, moderate, severe). At 6, 12 and 24 months after RTX, using the same semi-quantitative scoring system, HRCT chest findings were ranked as worsening, stable or improving.

Multiple patient characteristics (Table 1) were tested for their correlation with each outcome. For some variables, nonparametric statistical methods were used due to a small number of non-missing variables. The Spearman rank correlation and Wilcoxon signed rank test were used to determine % change in FVC and DLCO at 6, 12 and 24 months after RTX treatment.

Table 1

Results:

Table 2

1. Most patients were female and African American with median age of 60.

2. HRCT Chest findings after RTX showed either improvement or stability at 6, 12, 24 months (96.3%, 94.7%, and 100% respectively).

3. Given multiple missing variables, there was no statistical difference for changes in FVC and DLCO, however observed changes improved with the median %change ranging from 1 to 3.5. The largest changes were observed for FVC and DLCO at 1 year and DLCO at 2 years after treatment (12.7%, 7.1% and 6.9%, respectively) (table 2).

4. CTD duration showed negative correlation with FVC change at 1 year post-RTX with estimated 1.1% decrease in FVC for every year increase in CTD. ILD duration showed negative correlation with DLCO change at 2 years post-RTX with estimated 3.9% decrease in DLCO for every year increase in ILD.

Conclusion:

RTX is an effective therapy for CTD-ILD. Our study suggests that using RTX earlier in the disease course may have long-term positive impact. RTX may help fill an unmet therapeutic need for CTD-ILD but larger randomized clinical trials are needed.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/efficacy-of-rituximab-for-connective-tissue-disease-ctd-associated-interstitial-lung-disease-ilda-single-center-study-of-47-patients/