FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T David G. Maloney, Barbara Pender, Erin McCarthy, and Daniel P. Gold Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Patient specific active idiotype immunotherapy with immunoglobulin idiotype is a promising new therapy for follicular non-Hodgkin's Lymphoma (NHL). Response to therapy may include both humoral and cellular anti-idiotypic immunity, but it is not clear which is most important. Background Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Prior studies have suggested that immunoglobulin FCgammaRIIIa (FC  RIIIa ) polymorphisms at position 158 valine (V) or phenylalanine (F) affect the response to treatment with rituximab as well as outcomes from idiotype immunotherapy following objective response to chemotherapy. Background Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Polymorphisms in FCgRIIIA (CD16) Influence PFS following Single Agent Rituximab CD16 Amino Acid 158 encodes valine (V) or phenylalanine (F) - V/V phenotype associated with higher affinity interaction with human IgG1 - F/F phenotype associated with lower affinity interaction and poorer outcome to rituximab Initial therapy of low-tumor burden follicular NHL patients treated with rituximab 375 mg/m2 x 4 weeks (Cartron G, Blood 99:754, 2002) - Treatment of patients with relapsed follicular NHL (Weng and Levy, JCO 21:3940, 2003) - Also observed in Waldenstrom’s but not in CLL (Treon S, ASH 2003, Farag S, Blood 103:1472, 2004) Background: FC  RIIIA Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Mitumprotimut-T is a patient-specific and B-cell tumor-specific idiotype (Id) protein chemically conjugated to keyhole limpet hemocyanin (KLH), a potent non-specific immunogenic protein Mitumprotimut-T induces a cellular and humoral immune response to the Id protein expressed by the patient’s own tumor, leading to active immunization against the tumor while sparing normal B-cells Background Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Mitumprotimut-T is co-administered with granulocyte-macrophage colony-stimulating factor (GM-CSF) to further enhance immune anti-Id immune responses The Id protein is produced by proprietary recombinant technology; ~8 weeks from biopsy to final product Background Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T To assess the correlation between long term progression free survival (PFS) following combined rituximab + mitumprotimut-T (Id-KLH) treatment and FC  RIIIa (CD16) polymorphism expression To assess the correlation of FC  RIIIa polymorphisms and outcomes from idiotype immunotherapy following treatment with rituximab Objective Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Key Inclusion Criteria: – Histologically confirmed Grade 1 or 2 follicular B-cell lymphoma (WHO classification) – Treatment-naïve, relapsed/refractory to chemotherapy, or relapsed following prior ≥ 6-month response to rituximab – ≥8 weeks between completion of any prior lymphoma therapy and start of rituximab on study – Measurable disease (≥2 cm) following node biopsy – Performance status (ECOG) of 0, 1 or 2 Methods Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Key Exclusion Criteria: – >3 prior chemotherapy or anti-CD20 regimens – Prior fludarabine – Concurrent immunosuppressive therapy (e.g., high-dose steroids) Methods Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T PCR primers were designed to specifically amplify the regions of interest in FC  RIIIa The FC  RIIIa genotypes of 55 rituximab-naïve patients treated on a Phase II trial of mitumprotimut-T were determined using a SSCP method with genomic DNA Bands were sequenced to confirm the presence of the polymorphism Methods Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

SSCP Analysis for FC  RIIIa Polymorphism at position 158 Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia. H2OH2O V/VV/F F/F V/VV/F F/F 200 bp 100 bp PCR SSCP

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Rituximab: 375 mg/m2 weekly infusion x 4 weeks. Subjects with stable disease (SD) or an objective response (CR or PR) to rituximab were eligible for mitumprotimut-T Mitumprotimut-T: 1 mg sc on Day 1 of each course. Courses administered monthly x6, bimonthly x6, and then every 3 months until disease progression or significant toxicity GM-CSF: 250 mcg/day sc on Days 1-4 of each course; same injection site as mitumprotimut-T CT scans: Obtained every 3 months; read by an independent radiologist blinded to clinical data Response assessment: Central review using modified IWG response criteria (Cheson et al, J Clin Oncol 1999;17: ) Study Schema And Treatment Regimen Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

Study Schema and Treatment Regimen Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia Months CT Scans Mitumprotimut-T + GM-CSF Rituximab Mitumprotimut-T Production Biopsy Cytoreduction Induction Maintenance

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T DNA was isolated from all 55 patients and successfully analyzed by SSCP for polymorphisms at position 158 of FC  RIIIa: – V/V: 9 (16%) – 27 (49%) – V/F 19 (35%) Results Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T 95 patients received rituximab and were evaluable. 38 Treatment-naïve (T-N) patients 57 Relapsed/Refractory (R/R) patients - 25 of the 57 R/R pts were rituximab-naïve - 32 of the 57 R/R pts had previously received rituximab ± chemotherapy 6 of 95 patients were progressive disease (PD) following rituximab and were ineligible to receive mitumprotimut-T (Id KLH) 89 patients received mitumprotimut-T following rituximab Patient Enrollment: Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T 4 patients who progressed following rituximab and therefore did not receive mitumprotimut-T were excluded from this analysis All 55 patients in this analysis had follicular NHL with a median age of 55 years 35 patients were treatment naïve and 20 had relapsed following prior chemotherapy Treatment Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T 4 patients who progressed following rituximab and therefore did not receive mitumprotimut-T were excluded from this analysis All 55 patients in this analysis had follicular NHL with a median age of 55 years 35 patients were treatment naïve and 20 had relapsed following prior chemotherapy DNA Sample Availability Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Polymorphism at Position 158: Distribution Among Evaluable Subjects T-N = treatment-naïve, R/R = relapse-refractory. Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia. GroupNV/VV/FF/F All8412 (14%)34 (41%)38 (45%) R/R467 (15%)18 (39%)21 (46%) T-N385 (13%)16 (42%)17 (45%) Rituximab naïve61 (38T-N, 23R/R) 10 (16%)21 (34%)30 (49%) Results

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T The 3 month response (post rituximab) was: – V/V: 5/9 (56%) – V/F: 9/19 (47%) – F/F: 17/27 (63%) The best response was: – V/V: 6/9 (67%) – V/F: 12/19 (63%) – F/F: 21/27 (78%) Results Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

Initial Overall Response Rate to Single Agent Rituximab Therapy, Among Rituximab-Naïve Patients According to FC  RIIIa Polymorphism at Position 158 The overall response rate is equal to the incidence of complete response and partial response: ORR = CR + PR. Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia. GroupNRituximab ORR All6154% V/V1050% V/F2152% F/F3057% Any V3152% Any F5155% ORR = CR+PR

Best ORR Achieved, TTP, and PFS with Combined Rituximab + Mitumprotimut-T Among Rituximab-Naïve Patients According to FC  RIIIa Polymorphism at Position 158 ORR = overall response rate; TTP = time to progression; PFS = progression free survival Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia. GroupN* Best ORR to combined rituximab + Id-KLH treatment Med. TTP (months)1 Yr. PFS4 Yr. PFS All5770%17.759%30% V/V967%19.655%29% V/F2162%20.858%34% F/F2778%17.762%28% Any V3063%19.657%33% Any F4876%17.760%30% * 4 Patients ( 3 FF & 1 VV) who were PD post rituximab did not qualify for mitumprotimut-T Id-KLH treatment and are excluded from the analysis for the combined treatment

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Median TTP was: – V/V: 19.5 months – V/F: 22.3 months – F/F 18 months The PFS at 1 year post initiation of rituximab was: – V/V: 57% – V/F: 61% – F/F: 68% Results Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T At the median follow-up of 3.5 years the PFS was: – V/V: 31% – V/F: 42% – F/F: 31% Results Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

PFS for V/V vs. V/F vs. F/F FC  RIIIa at Position 158 Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia V/F V/V F/F Months Progression Free %

PFS for V/V vs. V/F vs. F/F FC  RIIIa at Position 158 Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia Any F Any V Months Progression Free %

Antibody Responses to KLH and Id Among Long Term (> 3 years) Progression Free Survivors* (n=13) positive (+) negative (-) Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia. Patient FC  RIIIa GenotypeKLHId 1V/V+– V/F – 7 +– Patient FC  RIIIa GenotypeKLHId 8F/F+– 9 –– 10F/F++ 11F/F+– 12F/F+– 13F/F+– *As measured by ELISA

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T FC  RIIIa polymorphisms were not associated with response rate or time to progression following a treatment program consisting of single agent rituximab followed by idiotype vaccination with mitumprotimut-T in rituximab- naive patients Results from an ongoing randomized Phase III study will assess the efficacy of this combined therapy, but these data suggest that long term PFS in patients receiving an idiotype vaccine following rituximab may rely more on a cell mediated immune response rather than a humoral response to idiotype Conclusions Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T The distribution of FC  RIIIA polymorphisms at Position 158 in this study population is comparable to previously published data among FL patients. In the population of Rituximab Naïve FL patients (23 R/R and 38 T-N), there is no correlation with FC  RIIIA polymorphisms at Position 158 and initial response to 4 course Rituximab therapy nor with time to progression following idiotype immunotherapy with mitumprotimut-T +GM-CSF. Summary Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T  Long term progression free survival (> 3 years) following combined Rituximab plus mitumprotimut-T (Specifid™, Id-KLH, FavId®) therapy does not correlate with production of anti-idiotypic antibody suggesting long term PFS may rely more on a cell mediated immune response. Summary Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.

FC  RIIIa Receptor Polymorphisms Do Not Influence the Outcome of Treatment with Rituximab Followed by Active Immunotherapy with Mitumprotimut-T Lack of correlation with FC  RIIIA polymorphisms and long term PFS may suggest that if such an association does occur with Rituximab monotherapy, the addition of idiotype vaccine overrides the FC  RIIIA advantage. Results from an ongoing randomized PIII study due to be reported in July 2008 will assess the efficacy of this combined therapy and any potential role for FC  RIIIA polymorphisms. Summary Maloney DG et al. Abstract #3416. Presented December 10, 2007, at the 49th ASH Annual Meeting in Atlanta, Georgia.