Background/Purpose: The recommended therapeutic regime for Rituximab (RTX) in Rheumatoid Arthritis (RA), according to prescribing information, includes two 1000-milligram infusions given two weeks apart, every 6 months. However, this is often not the case in clinical practice, since both consensus documents  and information from clinical trials consider other alternatives. Our objective in this study was to analyze the pattern of use of RTX in RA in daily clinical practice.

Methods: This is a retrospective study that includes patients treated with RTX between 1998 and 2013 in a single university hospital. We reviewed medical records and collected demographic data, number of cycles, doses and intervals of RTX administered to the patients, response duration, as well as frequency and reasons of treatment discontinuation. Descriptive analysis was performed using the statistical package Stata v. 12.

Results: Ninety-three patients were studied, of which 83% were women. Median age at disease onset was 51 years with an interquartile range (IQR) of 39 to 60 years. Median age at the start of treatment with RTX was 60 [IQR: 51-70] years. Out of the 93 patients, 11 had negative rheumatoid factor. The number of cycles of RTX administered to each patient ranged from one to nine. Treatment was discontinued in 33% of the patients. The reasons for discontinuation were inefficacy (16%), adverse effects (7%) and others (10%). RTX was most commonly withdrawn during the first two cycles . The main data related to use of RTX in our study are summarized in the following table.

CYCLE  OF RTX	1	2	3	4	5	6	7	8	9	TOTAL
Patients (N)	93	78	53	45	35	25	12	10	5	356
Fixed regime 1(%)	16	10	13	11	6	0	0	0	0	11.2
Dose (mg)/cycle2	1956	1736	1711	1704	1735	1708	1727	1444	1250	1663
Response duration (months)	10	10	10	11	11	10	12.5	9.5	8	10.2
Administration interval (months)	10	11.6	10.3	11.4	13	14.8	13.6	9.9	–	11.8
ADMINISTRATION YEAR	1998-2005	2006	2007	2008	2009	2010	2011	2012	2013
Patients (N)	7	12	25	36	50	56	44	44	35
Fixed regime1(%)	36	33	13	16	17	6	4	0	0
Dose (mg)/cycle2	2000	1944	1946	1953	1733	1716	1652	1818	1485
Response duration (months)	15	10	11	10	9	10	10	12	7
Administration interval (months)	16	11.2	12	10.4	9.4	10.3	11.5	13.1	–
Cost Savings compared to fixed regime3 (%)	60	42	47	41	42	48.5	50	54.5	–

¹ Fixed regime: administration of two 1000-milligram infusions given 2 weeks apart, every 6 months
² Mean value
³Calculated percent saving in direct yearly drug cost compared to the fixed regime .

* All unspecified data are given in median value.

Response duration in males tended to be longer [12 months; IQR: 8-13] than in females [10 months; IQR: 7-12], but this didn’t reach statistical significance (p = 0’11, Mann-Whitney’s  test). Longer response duration was observed in patients with a longer RA history (r = 0.24, P = 0.001, Pearson’s test).  RTX dose per cycle did not modify the  response duration (1 vs 2 grams, 9.5 and 10 months respectively).

Conclusion: Our data show that, in daily clinical practice, RTX is more frequently used on demand, tending to abandon the fixed regime of 2 grams every six months. In addition we observe a tendency to an increased use of 1 gram cycles with time. This results in cost savings without apparent decrease in healthcare quality.

References :
– Bredemeier et al.  Low- versus high-dose Rituximab for Rheumatoid Arthritis: A systematic review and meta-analysis. Arthritis Care Res (Hoboken). 2013 Aug 27. doi: 10.1002/acr.22116.
– Martín Mola et al. Consensus on the Use of Rituximab in Rheumatoid Arthritis. A document with evidence-based recommendations. Grupo de Expertos en Rituximab. Reumatol Clin. 2011;7:30-44

---

« Back to 2014 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/regime-of-use-of-rituximab-in-patients-with-rheumatoid-arthritis-in-daily-clinical-practice/