1222 - The Effectiveness of Abatacept in a Large Rheumatoid Arthritis Real World Practice:  Changes in the HAQ Over Time and Durability of Response

Monday, November 7, 2011: 9:00 AM-6:00 PM
Hall F2 - Poster Hall (McCormick Place West)
Janet E. Pope1, Emmanouil Rampakakis2, John S. Sampalis2 and Olivier Desjardins3, 1St. Joseph's Health Care, University of Western Ontario, London, ON, 2McGill University & JSS Medical Research, Montreal, QC, 3Bristol Myers Squibb Canada, St. Laurent, QC
Presentation Number: 1222

Background/Purpose: A large Canadian database was used to determine effectiveness of abatacept in real world RA patients by examining changes in health assessment questionnaire (HAQ), and the proportion of patients continuing abatacept over time.

Method: RA patients administered abatacept in routine practice via the Orencia Response Program network, between Aug. 2006 and Feb. 2011 who received clinic or home infusions and had at least one follow-up evaluation were included. The number needed to treat (NNT) to improve HAQ by at least the minimally important difference (MID ≥ 0.22) and abatacept survival until last follow up were calculated overall, and for those post DMARD and post TNFi.

Result: Among the 2,929 patients enrolled, 1,771 (60.5%) were eligible for the study (mean age 57.6 years; disease duration 16.5 years (SD 11.0), 77% female, 79.2% had past TNFi) with a mean (SD) follow up of 13.8 (12.3) months. Mean (SE) durability of treatment was 26.8 (0.53) months; where 66% were still on abatacept at 12 and 53% at 24 months (Figure 1). The survival was longer where abatacept was the first biologic vs. post TNFi (P=0.0001) (Figure 2). In abatacept as 1st biologic, 70% achieved MID in HAQ vs. 71% if post TNFi (P=0.65) with NNT=1.4 in each group and there were also no differences in % achieving MID comparing no past biologic to 2, 3 or 4 pervious biologics. For those staying on abatacept, the mean improvement in HAQ increased over time; changing at 6,12, 18 and 24 months by -0.29, -0.41, -0.45 and – 0.51 respectively with no difference between abatacept as first biologic vs. post TNFi (Table 1). Increased baseline HAQ (OR 2.13 (1.89, 2.39)) and less years of RA (OR 0.98 (0.97, 0.99)) were significant predictors of achieving the MID for HAQ.    

Conclusion: The results demonstrate that abatacept is effective in improving function in RA despite long disease duration.  For those still on abatacept, HAQ continued to improve over the first 2 years. The real world durability of abatacept is better as first biologic; however the overall survival in this large study seems similar to other biologics despite 79% having previous TNFi exposure. 

Table 1. Characteristics and Patient Disposition

Parameter

Post DMARD

N=369

Post TNFi

N=1,402

Total Cohort

N=1,771

P-Value

Mean (SD) Age (years)

58.80 (13.65)

57.28 (13.10)

57.60 (13.23)

0.0496

Mean (SD) Time Since Diagnosis (years)

13.25 (10.83)

17.36 (10.92)

16.53 (11.02)

<0.001

Female Gender: n (%)

260 (70.46)

1,107 (78.96)

1,367 (77.19)

<0.001

Disease Severity:

n (%)

Mild

1 (0.27)

4 (0.29)

5 (0.28)

0.736

Moderate

22 (5.96)

104 (7.42)

126 (7.11)

Severe

346 (93.77)

1,291 (92.08)

1,637 (92.43)

NA

0 (0.00)

3 (0.21)

3 (0.17)

Baseline HAQ

1.45 (0.71)

1.72 (0.69)

1.66 (0.70)

<0.001

 

12 Months

-0.34 (0.66)

-0.43 (0.67)

-0.41 (0.67)

0.207

24 Months

-0.48 (0.70)

-0.52 (0.70)

-0.51 (0.70)

0.786

36 Months

-0.36 (0.69)

-0.60 (0.71)

-0.58 (0.71)

0.297

Mean (SD) Durability of Treatment

26.12 (0.86)

25.75 (0.58)

26.79 (0.53)

<0.001

% on Abatacept (Survival Estimate)

12 Months

74

64

66

24 Months

65

50

53

36 Months

56

43

46

 

Figure 1. Overall Durability of Abatacept

Parameter

Value

Total N

1,771

N (%) Failed

672 (37.94)

 N (%) Censored

1,099 (62.06)

Mean  (SE) Durability of Treatment (months)

26.79 (0.53)


Keywords: rheumatoid arthritis (RA)

Disclosure: J. E. Pope, None; E. Rampakakis, None; J. S. Sampalis, None; O. Desjardins, Bristol Myers Squibb Canada, 3 .