Background/Purpose:

Small series have suggested that rituximab (RTX) may be effective as rescue-therapy for connective tissue disease-associated interstitial lung disease (CTD-ILD). We sought to describe our center’s experience of the outpatient use of RTX in patients with a diverse spectrum of CTD-ILD.

Methods:

We identified all patients with CTD-ILD who (1) received at least one cycle of RTX as an outpatient between January 2008 and May 2014, (2) had at least one thoracic HRCT scan, and (3) pulmonary function testing pre- and post-initial RTX treatment. We extracted data from the medical record for the following: demographics, concurrent immunosuppressive medications, pulmonary function and thoracic imaging, RTX-associated side effects, infection history, and discontinuation rate. We analyzed the % predicted forced vital capacity (FVC%) closest to pre- (mean 131.8±204.6 days) and post-initial RTX administration (mean 121.7±97.2 days). T-tests were used for continuous variables analysis and Fisher’s exact test was used for contingency table analysis.

Results:

The cohort comprised 24 subjects with a diverse spectrum of CTD-ILD.

Table 1: Clinical characteristics

There was no change in mean FVC% pre- and post-initial RTX cycle (71.3±18.6 vs. 71.6±17.9, p=0.87). Post-RTX, in 9 subjects (38%) FVC% improved (4 by >10%), and in 15 subjects (63%) FVC% declined (3 by >10%). In the 15 subjects with RA, FVC% was unchanged (70.4±20.2 vs. 74.5±19.7, p=0.18). Post-RTX, in 9 RA subjects (60%) FVC% improved (4 by >10%), and in 6 subjects (40%) FVC% declined (1 by >10%). In those without RA (n=9), FVC% declined significantly (72.7±15.4 vs. 66.8±12.8, p=0.015; 3 by >10%).

Pre- and post-RTX change in FVC% were 4.2±17.4 in RA vs. -8.6±7.2 in non-RA (p=0.025). RA subjects were also more likely to have improved FVC% (p=0.0068).

Sixteen (67%) subjects were on a concomitant corticosteroid-sparing medication. Thirteen (54%) were on prednisone at RTX initiation (mean dosage 10.2±16.2 mg) and 9 (38%) remained on prednisone at 6 months post-RTX (mean dosage 5.6±11.0 mg) (p=0.27).

Five infectious episodes (2 upper respiratory tract infections, 2 lower respiratory tract infections and 1 disseminated Herpes Zoster infection) occurred in 5 different subjects within 6 months post-initial RTX cycle. An additional 11 infectious episodes (mostly upper or lower respiratory tract infections) occurred in 5 of 12 subjects that received more than 1 RTX cycle (mean observation period of 35.6±19.3 months and 66 RTX cycles).

Conclusion:

Treatment of RA-ILD and other forms of CTD-ILD with RTX was associated with variable effects on pulmonary physiology and our series suggests a possible beneficial role for RTX in RA-ILD. RTX treatment was associated with modest corticosteroid sparing effects and a sizeable number of post-infusion infections. RTX warrants prospective study to better assess its role in managing RA-ILD and other CTD-ILD.