Dark teal text shows timing of sampling for B and T cell counts and for immune response
*say something in the title about the result, more thought on title Legend: T and B cell counts of individual patients enrolled in the 3M rest and 6M rest post rituximab cohorts. Horizontal bar represents the population median and the “whiskers” represent the inter-quartile range. Pre-R: cell numbers prior to first rituximab treatment (on average 9 days prior) Imm1: cell numbers immediately before the first immunization Imm4: cell numbers immediately before the fourth immunization Imm8: cell numbers immediately before the eighth immunization 8 Wks post: cell numbers 8 weeks after the eighth immunization Results: The absolute B cell numbers before rituximab treatment in both the 3M rest and 6M rest cohorts were generally low or even below normal for a significant numbers of patients, possibly due to the effect of prior chemotherapy treatment. Although patients enrolled in 3M rest and 6M rest cohorts were highly similar in term of age, gender, and disease status, the absolute B cells numbers before rituximab in the 3M rest cohort were generally lower than those in the 6M rest period. In both cases, B cell counts are expected to be essentially zero post rituximab. As expected, the absolute numbers of B cells after rituximab treatment were significantly suppressed (Imm1) and progressively increased with time (Imm4, Imm8, and 8 Wk Post) in both cohorts. The absolute T cells numbers before rituximab treatment in both the 3M rest and 6M rest cohorts were within normal ranges for the majority of patients. These numbers did not vary significantly throughout the immunization and the 8-week follow up.
There is a statistically significant difference between trial 2002-09, 3M and 6M Rest, and 9902B. There is also a significant difference between 2002-09 3M and 6M Rest periods.
Each B cell normally produces a unique B cell antigenic receptor (BCR, aka surface immunoglobulin, sIg) in order to give the cell immune specificity. The BCR defines the specific B cell as unique. NHL is a clonal population of tumor cells. The idiotype is the collection of unique antigenic determinants present in the variable region of the clonal immunoglobulin expressed by the B cell.
Cancer and Inflammatory Diseases Immunotherapy Building Bridges Between Discovery, Preclinical, and Clinical Research
Active immunotherapy following rituximab treatment: from nonclinical study to the clinic
Clinical Study Design Immunization efficiency following rituximab Rituximab 4 Doses (N=90)* Restage at 8 Weeks: CR, CRu, PR Patients who failed chemotherapy Study 2002-09 Sampling times for T and B cells and immune response *Third cohort (N=16) of immunized patients were not eligible for either 3M or 6M Rest groups. Screen failures (N=33) not eligible for immunization. Leonard J.P. et al., ASCO 2006 Follow- up 6-month Rest Period (N=23) 8 Immunizations Q 2 weeks Follow- up 3-month Rest Period (N=18) 8 Immunizations Q 2 weeks
Patients treated with rituximab have dramatically reduced B cell numbers B Cells (CD19 + ) T Cells (CD3 + ) 3M rest period 3M rest period 6M rest period 6M rest period Leonard J.P. et al., ASCO 2006 Post-R Post-R
Patients treated with rituximab have significantly lower humoral response against KLH Leonard J.P. et al., ASCO 2006 Analysis of variance (treatment effect) 9902B 2002-09 3M Rest p < 0.0001 9902B 2002-09 6M Rest p < 0.0001 2002-09 3M Rest 2002-09 6M Rest p < 0.05
B Cell Surface Targets CD22 CD20 CD19 BCR Idiotype frequency ~1/10 10 V region framework frequency ~ 1/20 C region frequency ~ 1/2 CD19, CD20, CD22 frequency 1/1 Sornasse T. et al., ASH 2007
45 Ig heavy chain V genes
70 Ig light chain V genes
Ig V gene sub-families share common structures
Ig include 1 light and 1 heavy chain
Concept of a selective mAb immunotherapy of B cell lymphomas Sornasse T. et al., ASH 2007
mAbs specific for Ig variable region framework directly kill lymphoma cell line in vitro Anti-Ig VL mAb: Cell line A Anti-Ig VH mAb: Cell line B Lymphoma cell lines were incubated for 48 hours in the presence of mAbs. Dead cells were identified by flow cytometry as 7-AAD-positive cells.
Is it possible to deplete target B cells in vivo, in the presence of high level of soluble antigen ?
Sornasse T. et al., ASH 2007 Anti-Ig mAb Serum Ig Target B Cell
Incorporate Hypothesis Testing to Preclinical Study
Study type: Exploratory toxicology
Test article: anti-human Ig VH 3.23
Model: cynomolgus monkeys
Similar to human regarding frequency of target cells, levels of soluble antigen, and affinity for Ig sub-family
3 Dose levels: 10, 40, and 100 mg/kg
4 animals / group: 2 Males / 2 Females
Treatment regimen: 4 x q3-4 d
Exploratory end points
Frequency of target B cells and of total T and B cells
Sornasse T. et al., ASH 2007
Anti human Ig VH 3.23 mAb does not significantly affect the frequencies of B and T lymphocytes in vivo Control Group Dose Group: 10 mg/kg Dose Group: 40 mg/kg Dose Group: 100 mg/kg Legend Infusions Flow cytometry Schedule of events Sornasse T. et al., ASH 2007 Study Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Anti human Ig VH 3.23 mAb depletes target B cells in vivo (Study 2) Sornasse T. et al., ASH 2007
Inflammation of the gastro-intestinal tract that is not due to specific pathogens.
Crohn’s Disease: can affect any part of the digestive tract.
Ulcerative Colitis: limited to lower part of large intestine.
Disease of industrialized countries.
Smoking reduces risk of UC but increases risks of CD.
Basic Differences Between CD and UC Ulcerative Colitis Crohn’s Disease Lesion characteristics : - Strictly mucosal. - Continuous and diffuse. - Progress from distal portion of GI tract. Lesion characteristics : - Transmural ( may involve layers as deep as adventitia ). - Scattered and focal. - May appear anywhere along lower GI tract.
Daclizumab does not significantly affect CD3/ CD28-induced proliferation of human PBMC The PBMC of adult volunteers were stimulated with CD3/ CD28 beads for 72 hours in the presence of graded doses of daclizumab. Results are presented as the Average of the relative proliferation to no-daclizumab control ± SEM Sornasse T. et al., AAAAI 2005 Potential effect on cytokine production is not affected by T cell number
Daclizumab strongly inhibits the secretion of pro-asthmatic Th2 cytokines The PBMC of healthy adult volunteers were stimulated with CD3/ CD28 beads for 72 hours in the presence of graded doses of daclizumab. Results are presented as the Average of the relative cytokine levels to no-daclizumab control ± SEM Sornasse T. et al., AAAAI 2005
Daclizumab inhibits the secretion of pro-asthmatic Th0 cytokines The PBMC of healthy adult volunteers were stimulated with CD3/ CD28 beads for 72 hours in the presence of graded doses of daclizumab. Results are presented as the Average of the relative cytokine levels to no-daclizumab control ± SEM Sornasse T. et al., AAAAI 2005
Daclizumab partially inhibits the secretion of pro-inflammatory Th1 cytokines The PBMC of healthy adult volunteers were stimulated with CD3/ CD28 beads for 72 hours in the presence of graded doses of daclizumab. Results are presented as the Average of the relative cytokine levels to no-daclizumab control ± SEM Sornasse T. et al., AAAAI 2005