Decrease In Peripheral Lymphocyte Count Research Articles

P558 Etrasimod for the treatment of ulcerative colitis: analysis of infection rates from the phase 3 ELEVATE UC 52 and ELEVATE UC 12 clinical trials

Abstract Background Infections are an important safety concern in patients with IBD and may be due to its therapies, such as corticosteroids. Etrasimod is an investigational, once-daily, oral, selective sphingosine 1-phosphate receptor 1,4,5 (S1P1,4,5) modulator in development for the treatment of moderately to severely active ulcerative colitis (UC). The biologic effect of etrasimod leads to selective and reversible lymphocyte retention in lymph nodes with a decrease in peripheral lymphocyte count. We report the infection events from the phase 3 ELEVATE programme. Methods Infection events were evaluated in the pivotal UC pooled safety analyses set comprising two phase 3 studies: ELEVATE UC 52 (NCT03945188) and ELEVATE UC 12 (NCT03996369). Subjects (16-80 years) with moderately to severely active UC were randomised 2:1 to once-daily etrasimod 2 mg or placebo (PBO). We report the n (%) and exposure-adjusted incidence rate (EAIR) of infections including serious infections, severe infections, opportunistic infections (including tuberculosis), and herpes infections. Infections were considered adverse events of special interest (AESI) if they were severe (≥ CTCAE Grade 3), were opportunistic infections, or were herpes zoster or herpes simplex infections. Results From the pooled ELEVATE UC 12 and ELEVATE UC 52 trials, 527 subjects received ≥1 dose of etrasimod 2 mg (265.6 subject-years of exposure) and 260 subjects were randomised to PBO (103.0 subject-years of exposure). Infections were similar between treatment groups (etrasimod: 99 [18.8%], EAIR=0.41; PBO: 46 [17.7%], EAIR=0.52). The most frequent infections in both groups were COVID-19, urinary tract infections, and nasopharyngitis (Table 1). Serious infections occurred in 3 (0.6%) subjects in the etrasimod arm (EAIR=0.01) and 5 (1.9%) in PBO arm (EAIR=0.05). Two cases of herpes zoster were reported in each treatment group (etrasimod: 0.4%, EAIR<0.01; PBO: 0.8%, EAIR=0.02); these were localised and nonserious. One opportunistic infection was reported in each arm (etrasimod: subject withdrew from the study on day 20, the AE of Cytomegalovirus infection [Grade 2] was reported on day 36; PBO: tuberculosis [Grade 2]). Overall, 3 cases of infection led to discontinuation: 2 in the etrasimod arm (both mild) and 1 in the PBO arm (Table 2). No subject with an absolute lymphocyte count <0.2×109/L subsequently reported a serious/severe or opportunistic infection. There were no deaths. Conclusion In these trials, etrasimod-treated subjects reported no increase in infections relative to PBO. Serious infections and herpes zoster were more commonly reported in the PBO-treated group. Longer-term follow-up data from the ongoing 5-year open-label extension will further characterize the etrasimod safety profile.

The kinetics of γ-H2AX during radiotherapy of head and neck cancer potentially allow for prediction of severe mucositis.

BackgroundThe aim of the study was to evaluate the changes in γ-H2AX expression in peripheral blood lymphocytes (PBL) according to severity of radiation-induced mucositis.Patients and methodFifty patients with head and neck cancer treated with radiotherapy (RT) or chemoradiation were included in the study. Blood samples were collected before treatment to measure baseline γ-H2AX levels. Second sample was taken 45 minutes after the first RT fraction and then once a week, 45 min after irradiation. In patients treated with chemoradiation the blood sample was taken the day after chemotherapy. Mucositis was evaluated once a week and reported according to CTCAE v4 and RTOG/EORTC scales. PBL were analyzed with flow cytometry and level of H2AX phosphorylation at every time point was evaluated.ResultsIn 35 patients mild to moderate (grade 1–2) mucositis was observed and 15 patients developed severe (grade 3) mucositis. No cases of grade 4 mucositis were observed. The difference in baseline levels of γ-H2AX between groups with mild and severe mucositis was statistically insignificant (p = 0.25). The statistically significant difference in γ-H2AX level was observed in week 7 of treatment (p = 0.01). No significant differences in γ-H2AX level were found neither between group treated with concomitant chemoradiation or RT alone neither between groups with and without common comorbidities. In the analysis of the kinetics of γ-H2AX during treatment, a statistically significant difference (p = 0.0088) between groups with mild and severe mucositis was observed. After fourth week of treatment levels of γ-H2AX decreased significantly in the group with severe mucositis and increased in patients with mild side effects. The observed difference was not caused by the decrease in peripheral lymphocyte count, which was similar in both groups.ConclusionsPresented results indicate that severity of radiation-induced mucositis does not correlate directly with γ-H2AX levels measured in vivo in PBL. Prediction of mucositis grade based on γ-H2AX level is not yet possible, either before treatment or early during treatment, but preliminary results, indicating significant differences in γ-H2AX kinetics between groups, encourage further studies.

Abstract 2447: Transient lymphocyte decrease due to adhesion & migration following treatment with catumaxomab (anti-EpCAM x anti-CD3) in vivo

Abstract Catumaxomab is a trifunctional, bispecific antibody targeting EpCAM and CD3 which redirects T-cells to EpCAM expressing tumor cells and is able to evoke T-cell cytotoxic responses. The hybrid Fc region of catumaxomab provides a third functional binding site, which is able to bind and activate Fcγ receptor (FcγR)-positive accessory cells. In clinical trials a transient decrease in peripheral blood lymphocyte counts was observed following i.p. administration of catumaxomab. Lymphocyte decrease may be a result of either decreased production or increased destruction of lymphocytes, redistribution of lymphocytes or various unknown / multifactorial pathogeneses. We determined whether the observed transient decrease in patients might be due to antibody induced adhesion of lymphocytes to endothelial cells or to migration of lymphocytes into the tissue. Therefore, we investigated the influence of catumaxomab on adhesion of human T cells to endothelial cells in vitro. Catumaxomab physiologically activated T-cells by increasing expression of the activation marker CD69 and induced the release of cytokines, including TNFα and IFNγ. TNFα increased expression of adhesion molecules CD54 and CD62E on endothelial cells. Furthermore, catumaxomab dose-dependently increased adhesion of T cells to endothelial cells, and the adhesion was further increased when the endothelial cells were preactivated with TNFα. Thus, catumaxomab increases adhesion of T-cells to endothelial cells, which is due to antibody mediated upregulation of adhesion molecules on T-cells and production of cytokines that upregulate endothelial cell adhesion molecules. Furthermore, we showed that treatment of BALB/c mice with the related trifunctional antibody BiLu (anti-human EpCAM x anti-mouse CD3), that binds to mouse CD3, also resulted in a dose-dependent transient decrease in CD3+ T-cells (both CD4+ and CD8+) that returned to the normal range within 48 h. These results provide a rationale for the transient and reversible decrease in peripheral lymphocyte counts observed following catumaxomab administration in clinical studies, which is likely to be due to redistribution of lymphocytes and not due to depletion of circulating lymphocytes or stem cells. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2447.

Phase II, Single Center Study of Oral Forodesine in Patients with Advanced, Fludarabine-Treated Chronic Lymphocytic Leukemia (CLL).

Abstract 2369Poster Board II-346 Background:The prognosis of fludarabine-refractory patients is poor and the current salvage regimens produce low CR rates and are unlikely to improve long-term survival in this patient population. Forodesine, an analog inhibitor of the enzyme purine nucleoside phosphorylase (PNP), leads to rise in plasma dGuo levels followed by accumulation of dGTP in T-cells,that results in DNA breakdown and cell apoptosis. Forodesine has exhibited promising clinical activity in T cell leukemia with complete inhibition of PNP during therapy (Gandhi et al, Blood 106:4253, 2005). Previous in-vitro studies conducted by our group demonstrated that forodesine induces caspase dependent cell death in primary CLL cells by accumulating high intracellular dGTP in CLL cells (Balakrishnan et al, Blood 108:2392, 2006). This provided the rationale to test forodesine in B-CLL. Aims:i) to investigate the efficacy (CR + PR) of forodesine in treating patients with advanced, fludarabine-treated CLL, ii) to evaluate the toxicity, duration of response, disease-free survival and overall survival associated with treatment with forodesine, and iii) to correlate PK/PD data of forodesine in CLL with its clinical activity. Methods:Patients with primary resistance to fludarabine-based therapy (no CR or PR) or with progressive disease after response to prior fludarabine based regimen were eligible. The forodesine dose was 200 mg oral once daily, administered continuously up to a maximum of 24 weeks. Blood samples were collected on days 1-5 and day 28 and pharmacokinetic and pharmacodynamic parameters were determined. Ex vivo incubation with forodesine and dGuo were also performed in CLL lymphocytes to compare the treatment effects in vivo and ex vivo investigations. Results:8 patients were treated, the median age was 62 years (range 51-68), 7 males, median absolute lymphocyte count 35.85 (range 1.4-156.66) × 109/L, median serum beta 2 microglobulin level was 6.45 (range 3.6-16.3) mg/L. Six patients had Rai stage III-IV disease, the, median number of prior therapy was 5 (range 1-10), 5 patients were fludarabine refractory, 5 were ZAP-70 positive. Seven patients are evaluable for response and toxicity. Two patients had a transient decrease in their absolute lymphocyte count to normal level after the first 4 weeks, but it was short lasting. In the other 5 patients, the WBC counts increased progressively and in 3 patients there was also progression in lymphadenopathies. The toxicities observed were mild and included fatigue, bronchitis, diarrhea and low grade fever. Myelosuppression was transient and included neutropenia thrombocytopenia in 3 patients. One patient had pneumonia.The steady-state level of forodesine, measured on day 2, 3, 4, and 5, ranged between 200-1300 nM (n=8). At these concentrations, PNP inhibition in circulating RBCs, ranged between 57 and 89% (n=8). With this extent of PNP inhibition, steady-state dGuo concentration was a median 1.8 μM (range, 0.56 – 4.4 μM, n=8). The starting level of intracellular dGTP was a median 5 μM (range, 0.9 - 7.8 μM, n = 7) which increased to a median 12.5 μM (range 1.9 - 65 μM, n = 7). The circulating lymphocytes did not show annexin positivity above 10% during the first five days of treatment. To determine if CLL lymphocytes accumulate dGTP at high dGuo (10 and 20 μM) levels, we performed ex vivo incubations. Compared to in vivo, higher levels of dGTP were achieved ex vivo with a 10-50% increase in apoptosis. Conclusion:Oral forodesine showed activity with decrease in peripheral lymphocyte counts in 2 of 7 evaluable patients. However, all patients ultimately progressed while on treatment. Side effects were mild. The ex vivo biologic data and in vivo pharmacodynamic and clinical data suggest that forodesine has biological activity, and that alternative dosing schedules should be explored in future CLL trials. Disclosures:Off Label Use: Forodesine is not approved by FDA for treatment of CLL. Bantia:BioCryst: Employment. Gandhi:Mundipharma: Honoraria, Research Funding; Biocryst: Honoraria, Research Funding. Ravandi:Biocryst: Research Funding.

Sustained decrease of peripheral lymphocytes after allogeneic blood stem cell aphereses.

48 healthy donors underwent peripheral blood stem cell (PBSC) apheresis for allogeneic transplantation beginning on day 4 of G-CSF (2 x 5 microg/kg) mobilization. In one to four (median two) large-volume mononuclear cell aphereses, a median of 55.9 x 10(9) of lymphocytes (range 21.0-109.2 x 10[9]) were collected, an amount comparable to lymphocyte numbers removed by therapeutic lymphaphereses in autoimmune diseases. Mean peripheral lymphocyte counts decreased from premobilization values of 2.31 x 10(9)/l to 1.31 x 10(9)/l at a median of 34 d (1 month) and 1.53 x 10(9)/l at a median of 327 d (11 months). The decrease in peripheral lymphocyte counts was significantly correlated with the number of lymphocytes removed and the number of aphereses. Neutrophil and platelet counts returned to normal values after 1 month whereas monocyte counts and haemoglobin concentrations were significantly decreased at 1 month but not at 11 months.

Variations in Lymphocyte Counts Four Hours After Administration of Hydrocortisone in Patients With Chronic Lymphocytic Leukemia

The peripheral lymphocyte count and the number of large unstained cells (LUC) were investigated prior to and 4 hr after a single intravenous injection of 400 mg of hydrocortisone in 23 controls and 51 patients with lymphoid disorders (43 chronic lymphocytic leukemia, 3 cases of Waldenström macroglobulinemia, 2 hairy cell leukemias, 1 Sézary syndrome, and 2 cases of infectious mononucleosis). A reduction in both the peripheral lymphocyte counts and the number of LUC was observed in all normal controls, the mean decrease being 54% and greater than 60%, respectively, with differences according to age. In chronic lymphocytic leukemia (CLL), the peripheral lymphocyte count showed a variable response: decrease, no change, or increase. A correlation was shown to exist between a decrease in peripheral lymphocyte counts and anatomical-clinical staging: patients with involvement restricted to blood and bone marrow very often exhibited a drop in their peripheral lymphocyte count (p less than 0.01). In addition, the percentage of circulating T lymphocytes was higher (54%) in CLL patients whose peripheral lymphocyte count dropped than in other CLL patients (p less than 0.001).

Variations in lymphocyte counts four hours after administration of hydrocortisone in patients with chronic lymphocytic leukemia

The peripheral lymphocyte count and the number of large unstained cells (LUC) were investigated prior to and 4 hr after a single intravenous injection of 400 mg of hydrocortisone in 23 controls and 51 patients with lymphoid disorders (43 chronic lymphocytic leukemia, 3 cases of Waldenstrom macroglobulinemia, 2 hairy cell leukemias, 1 Sezary syndrome, and 2 cases of infectious mononucleosis). A reduction in both the peripheral lymphocyte counts and the number of LUC was observed in all normal controls, the mean decrease being 54% and greater than 60%, respectively, with differences according to age. In chronic lymphocytic leukemia (CLL), the peripheral lymphocyte count showed a variable response: decrease, no change, or increase. A correlation was shown to exist between a decrease in peripheral lymphocyte counts and anatomical- clinical staging: patients with involvement restricted to blood and bone marrow very often exhibited a drop in their peripheral lymphocyte count (p less than 0.01). In addition, the percentage of circulating T lymphocytes was higher (54%) in CLL patients whose peripheral lymphocyte count dropped than in other CLL patients (p less than 0.001).