Human anti-chimeric antibody levels correlate with lack of response and infusion reactions following infliximab therapy

polymorphism in exon 2 of TNF receptor It was identified. Only one coding polymorphism was present(Met196Arg, exon6 TNF-R-II). Homozygotemutant patients(Arg196Arggenotype) had a higher risk of non-responding (16.7% (1/6) responders), (p=0.0036) in comparison with heterozygotesand wild type (63.1% (53/84) responders).Median drop in CDAI was 61.5 in homozygote mutant in comparison with 114 in wild type and heterozygotes(P=0.091). Remission rate (CDAI<150) were 35.7% (30/84) in heterozygoteand wild type while none of the homozygutemutated (0/6) achievedclinical remission. This mutation may explain lack of response in about 14% of non-responders. The novel exon 2 silent mutation is in high linkage disequilibrium with he mutation in exon 6 (chi sqare=222, p<0.001) and can he used as a marker: Non-coding polymorphisms (TNF promoter 238, -308, -376, -1031, TNFR-I-609, +36 (exon 1), TNF-R-I11663, 1690 (3 UTR)) were also investigatedand found not to be associatedwith treatment response (P>O.5). Conclusion: Our finding may represent a first step in the pharmacngenetic definition of non-response to anti TNF-alpha therapies. Identification of further gene variations and prospectivetrails have to follow for a complete assessment of risks.

365 Allergic Reactions To Infliximab Retreatment Are Decreased In Pediatric Crohn's Disease (CD) Patients Compared To Adults. Suhra Kogathasan,Sotiros Vasilopoulos, Jeanne E. Emmons, Carolyn Raasch, Joseph P. Kim, Steven L. Werlin, Medical Coil of Wisconsin, Milwaukee,Wl; Alfonzo Martinez, Ellen L. Blank, Children's Hosp of Wisconsin, Milwaukee, Wl; Michael B. Levy, Kevin J. Kelly, David G. Binion, Medical Coil of Wisconsin, Milwaukee, Wl Backgroundand Aims: The anti-TNF-~ chimeric monoclonal antibody infliximah has proven highly efficacious in the treatment of CD in both adults and children. However,reinfusion with infliximab has beenassociatedwith immediateand delayedallergic reactions.We comparedthe rates of allergic reactions in adult and pediatric CD patients at a single institution over a 2 year time period. We also analyzedthe duration of time between infliximab infusions in these two CD patient populations and whether this might be associated with adverse allergic reactions. Methods:All pediatric and adult CD patients receiving multiple infliximab infusions between 10/98 and 12/00 at a tertiary referral center were included. Children were defined as age < 17. Immediate (anaphylactic/anaphylactoid)allergic reactionswere characterizedby decreasedblood pressureand difficulty breathingduring infusion. Delayedtype hypersensitivity reactions (DTH: type III reactions) produced diffuse arthralgia, fever and joint swelling in the days following repeat infliximah infusion. Duration between infusions was recorded in weeks. Results:There were a total of 53 repeat infusions in 32 children and 114 repeat infusions in 43 adults. 1/32 children experiencedan anaphylacticreaction while 10/43 adults experienced allergy with retreatment (3 immediate and 7 DTH reactions; p = <0.02). No DTH reactions were seen in children. 8/8 children tolerated repeat infliximab treatment after -> 20 week infusion interval (mean -+ SE: 36.8 -+ 6 weeks). In contrast, only 3/8 adults tolerated repeat infusion after -> 20 week infusion interval without allergic reaction (mean -+ SE: 41 _+ 6 weeks; p=<0.01). 5/7 pts with DTH reactions were on therapy with azathioprine/6-MP, methotrexateor corticosteroid, while 4/4 pts with anaphylacticreactionswere on concomitant immunosuppressive therapy. Conclusions:Allergic reactions to infliximab retreatment are significantly less frequent in CD children compared to adults, with no DTH reactions seen in pts younger than 17 years at our institution. Children tolerated >-20 week intervals between infliximab infusions, while adult CD patients frequently developed allergy. Patient age and duration of disease may be additional factors that impact on the development of allergic reaction to retreatmentwith chimeric monoclonal antibody therapy in CD.

363 Infliximab (Remicade) Treatment In Crohn's Disease And Astinuclear Antibody (ANA) Formation. Severine Vermeire, Maja Noman, Gert Van Assche, Nele Esters, Sofie Joossens, Filip Baert, Geert O'Haens, Univ Hosp Gasthuisberg - Oept Gastroenterology,Leuven 5elgium; Freddy Cornillie, Thomas Schaible, Centocor, Leuven Belgium; Lieve Godefridia, Xavier Bossuyt, Univ Hosp Gasthuisberg - Lab Immunology, Leuven Belgium; Paul Rutgeerts, Univ Hosp Gasthuisberg - Dept Gastroenterology,Leuven Belgium Introduction and Aims: Monoclonal chimeric antibodies against tumour necrosis factor-~ (Infliximab, Remicade®) are an efficacious treatment for patients with active refractory or fistulizing Crohn's disease (CD). This treatment may be associated with the induction of antibodiesto infliximab but also with antoantihodies.The incidenceof ANA following infliximab, as well as the target nuclear antigen against which ANA are directed, remain unclear. To further investigatethis issue, we undertooka systematic study in a large cohort of CD patients treated with infliximah. Methods: 116 CD patients receivinginfliximab were screenedfor ANA at different time points by immunofluorescence (on 1:40 diluted sera). Serum samples were obtained before the first infliximab dose and subsequentlyat every follow up visit. If the ANA titer was >-1/80, further examinations for double-stranded (native) DNA (using a semiquantitative crithidia and quantitativeFarr test), nucleosomes,histones (both ELISA) and ENA (counterimmunoelectrophoresis),were carried out. Results:Medianfollow up was 7.5 months (range 1-18 months). At baseline,7/116 (6.9%) patients were ANA positive. CumulativeANA prevalenceafter infliximab treatment was 581116 (50%). Almost half of these patients developed their antibodies already after the first infusion and >80% of patients became ANA+ after <3 infusions. 60% showed increasingANA fluorescenceover time, 34% remainedstable in titer and only 6% had decreasingtiters. Thirty-nine AHA+ patients (->1/80) were further specified: 17/39 (43.6%) were dsDNA+, 8/39 (20.5%) were anti-histone+, and none were anti-nucleosomeor ENApositive.Two patients(anti-dsDNAand anti-histoneANA+ ) developed a lupus-like syndrome with a butterfly rash and polyarthralgins but without major organ damage.Conclusion:In this cohort of CD patientsreceivinginfliximab, the cumulativeincidence of ANA was 50% after 18 months. Most patients developedANA at an early time point after the first infusion. ANA persisted up to 1 year after last infusion, and disappearanceof ANA over time was not observedin the 116 patients, although more and longer follow up is needed. The relationship between ANA positivity and side effects profile is currently being studied.

366 Outcome of Pregnancy in Women Receiving REMICADE® (Infliximab) for the Treatment o! Crohn's Disease or Rheumatoid Arthritis Jeffry A. Katz, Case Western ReserveUniv, Cleveland,OH; Gary R. Lichtenstein, Hosp of the Univ of Pennsylvania,Philadelphia,PA; Gregory F. Keenan, Deirdre E. Healy, Stephen J. Jacobs, Centocor, Inc, Malvern, PA Background/Objectives: Infliximab is a monoclonalantibodythat neutralizes the biological activity of tumor necrosis factor alpha (TNF~z)and is indicated for the treatment of Crohn's disease (CD) and rheumatoid arthritis (RA). Infliximah is labeled as Pregnancy Category 8. Although no evidence of maternal toxicity, embryotoxicity, or teratngenicity was observed when assessed in a mouse model, no information on the effect of infliximah in human pregnancy has been available. We now report on the outcome of pregnancy among 35 women who received REMICADE®. Methods: The infliximab postmarketing safety database was surveyedfor reports of pregnancy.Treating physicianswere then contactedto document the outcome of pregnancy and to collect additional information on infliximab treatment and patient characteristics. Results: Forty-two pregnancieswere identified in women with CD or RA treated with infliximab; follow-up information on pregnancyoutcome was availablefor 35 patients. Among patients with a diagnosis documented,all had CO exceptfor one RA patient. Patients ranged in age from 18 to 37 years. Among the 20 patients with exact dates of drug exposure documented, 6 received infliximab prior to pregnancy, 9 both prior to and during the first trimester, and 5 during the first trimester only. Among the 35 pregnancies with pregnancy outcome information obtained, 26 (74.3%) of these pregnancies resulted in live births, 5 (14.3%) in miscarriage, and 4 (11.4%) in therapeutic termination. Of the 26 live births, 2 infants were deliveredwith complicationsfrom mothers with CD. One praterm infant (gestational age of 23 weeks, birth weight of 681 grams) died 3 weeks following birth and one infant was bum with tetralogy of Fallot that was corrected surgically; this child ts reported to be otherwise healthy to date. Discussion: In these women treated with infliximab, the incidences of live births, miscarriages, and therapeutic terminations were consistent with those observed in a national cohort of healthywomen, i.e., 62%, 16%, and 22%, respectively. However, in both RA and CD, diseaseactivity is associatedwith the risk of fetal complications. Conclusion: Based on the data available in our postmarketing safety database, pregnant women exposed to infliximab have observed outcomes consistent with those expected in healthy women.

364 Human Anti-Chimeric Antibody Levels Correlate With Lack Of ResponseAnd Infusion Reactions Following Infliximab Therapy Richard J. Farrell, Mazen Afsahli, Kenneth R. Falchuk, Mark A. Peppercorn, Pierre Michetti, Beth Israel DeaconessMedical Ctr, Boston, MA BACKGROUNDIn trials and clinical practice,the majority of patients with active and fistulizing Crohn's disease respond to infliximab (Remicade) therapy. While most patients continue to respond to successive infusions (Continuous Responders-CR), a significant proportion may either lose their initial response (Lost Responders-LR), have only a partial or short-lived response(PartialResponders-PR)or haveno response(Non Responders-NR).The relationship between Human Anti-Chimeric Antibodies (HACA) formation and these patterns of response has not previously been studied. AIMS To determine the relationship between HACA levels and (1) patterns of responsefollowing infliximab therapy, (2) frequency of infusion reactions, (3) concurrent immunosuppressanttherapy. METHODS53 patients, all of whom received at least two infliximab (5mg/kg) infusions (total infusions, 175, range,2-13) were askedto grade their response at 2 wks post-each infusion as follows: 2 (response), t (partial response or response lasting < 4 weeks), or 0 (no response). Quantitative HACA and RemicadeELISA immunoassayswere performed blindly in duplicateon saradrawn on all patientsapproximately 24 weeks (range 8-52 wks) following their first infusion. HACA results were reported as follows: positive if the mean HACA result was >1.69/~g/ml and infliximab level was < 1.4 #g/ml; negativeif the mean HACAlevel was <1.69/~g/ml and infliximab level was <1.4 p.g/ ml and indeterminate if infliximab levels were >1.4/.@/ml. RESULTS37 patients responded to their initial infusion (70%) and 19 patients developed HACA (36%). There were 21 CR (40%), 15 LR (28%), 8 PR (15%) and 9 NR (17%). HACAlevelsamong CR were (iean+-S.E.) 0.79-+0.12. HACAlevelswere significantly higher among LR 11.5-+3.3, p = 0.002, PR7.0+-6.3, p=O.02, and NR 8.4-+3.6, p=O.O03 compared to CR. 0/21 CR developed HACAcompared to 11/15 LR (73%), 2/8 PR (25%), and 6/9 NR (67%). All 9 infusion reactions (5.1% of all infusions) occurred in HACA+ve patients. Concurrent immunosuppressants reduced HACA formation 8/34 (24%) v 11/19 (59%): p=O.Ol. 15% of HACA+ve patients responded to subsequent infliximab therapy. CONCLUSION28% of patients lost their initial response to infliximab. Loss of initial response, partial response, non-responseto infliximab, as well as infusion reactions appearsto be strongly related to HACAformation. A HACA+ve patient's risk of infusion reaction is greater than their likelihood of responding to subsequent infliximab therapy.

367 The Cytoprotsctive Effect of Isterleukino11 in Intestinal Epithelial Cells Involvesthe induction of the Small Inducible Heat Shock Protein 25 Mark J. Ropeleski,Jun Tang, Hung Yu Ren, Mark W. Musch, Eugene B. Chang, Univ of Chicago, Martin Buyer Lab, Chicago, IL Background:Heatshock proteins (Hsp) comprise an important epithelialcytoprotectivedefense against pro-inflammatory stressors associatedwith the intestinal milieu in IBD. Interleukin11 (IL-11) is a plniotropic cytokine with mncosal protective effects in animal models of IBD and is being investigatedfor the treatment of Crohn's Disease.The existence of a specific intestinal epithelialcytoprotectivemechanism responsiblefor the attenuationof mucosal injury observed in these instances, however, remains unclear. Aim: We first sought to determine whether IEC-18 cells express IL-11 receptors. We then tested the hypothesis that IL-11 induces Hsp's to protect the entemcyte from oxidant (monochloramine)-induced stress. Methods:Confluent IEC-18cells and NIH3T3non-epithelialcontrols were grown understandard conditions and exposedto various doses of IL-11 (0.1ng/ml to 500ng/ml) for 6 to 72 hours,

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