The effect of rituximab on vaccine responses in patients with immune thrombocytopenia.
ABSTRACT: B-cell depletion may impair vaccine responses and increase infection risk in patients with immune thrombocytopenia (ITP). We investigated the effects of rituximab on antibody and cellular responses to Streptococcus pneumoniae polysaccharide and Haemophilus influenzae type b (Hib) vaccines in ITP patients. Of 60 patients in the main trial, 24 patients received both vaccines 6 months after rituximab (n = 17) or placebo (n = 7). Among 20 evaluable patients, 3 of 14 (21%) in the rituximab group and 4 of 6 (67%) in the placebo group achieved a fourfold increase in anti-pneumococcal antibodies (P = .12). For anti-Hib antibodies, 4 of 14 (29%) and 5 of 6 (83%), respectively, achieved a fourfold increase (P < .05). Fewer patients in the rituximab group demonstrated Hib killing (2 of 14 [14%], 5 of 6 [83%], P < .05). Three of 14 rituximab-treated patients failed to respond to vaccines by any criteria. After vaccinations, preplasma cell blasts and interferon-γ-secreting T cells were reduced in rituximab-treated patients. Antibody responses were impaired for at least 6 months after rituximab. Cellular immunity was reduced in parallel with depleted B-cell pools. These findings have implications for the timing of vaccinations and the mechanism of infection after rituximab in ITP patients.
Project description:BACKGROUND: Rituximab has been widely used off-label as a second line treatment for children with immune thrombocytopenia (ITP). However, its role in the management of pediatric ITP requires clarification. To understand and interpret the available evidence, we conducted a systematic review to assess the efficacy and safety of rituximab for children with ITP. METHODOLOGY/PRINCIPAL FINDINGS: We searched MEDLINE, EMBASE, Cochrane Library, CBM, CNKI, abstract databases of American Society of Hematology, American Society of Clinical Oncology and Pediatric Academic Society. Clinical studies published in full text or abstract only in any language that met predefined inclusion criteria were eligible. Efficacy analysis was restricted to studies enrolling 5 or more patients. Safety was evaluated from all studies that reported data of toxicity. 14 studies (323 patients) were included for efficacy assessment in children with primary ITP. The pooled complete response (platelet count ? 100 × 10(9)/L) and response (platelet count ? 30 × 10(9)/L) rate after rituximab treatment were 39% (95% CI, 30% to 49%) and 68% (95%CI, 58% to 77%), respectively, with median response duration of 12.8 month. 4 studies (29 patients) were included for efficacy assessment in children with secondary ITP. 11 (64.7%) of 17 patients associated with Evans syndrome achieved response. All 6 patients with systemic lupus erythematosus associated ITP and all 6 patients with autoimmune lymphoproliferative syndrome associated ITP achieved response. 91 patients experienced 108 adverse events associated with rituximab, among that, 91 (84.3%) were mild to moderate, and no death was reported. CONCLUSIONS/SIGNIFICANCE: Randomized controlled studies on effect of rituximab for children with ITP are urgently needed, although a series of uncontrolled studies found that rituximab resulted in a good platelet count response both in children with primary and children secondary ITP. Most adverse events associated with rituximab were mild to moderate, and no death was reported.
Project description:This case-control study investigated immune thrombocytopenic purpura (ITP) risk following live, inactivated, and simultaneous vaccination, with a focus on infants aged?<?2 years. We matched case patients with ITP to one or two control patients with other diseases by institution, hospital visit timing, sex, and age. We calculated McNemar's pairwise odds ratios (ORs [95% confidence interval]) with 114 case-control pairs. The case group had 27 (44%) males and 22 (35%) infants, and the control group included 49 (43%) males and 42 (37%) infants. For all age groups, the McNemar's OR for ITP occurrence was 1.80 (0.54-6.84, p?=?0.64) for all vaccines. Among infants, these were 1.50 (0.17-18.0, p?=?0.50) for all vaccines, 2.00 (0.29-22.1, p?=?0.67) for live vaccines, and 1.00 (0.01-78.5, p?=?0.50) for inactivated vaccines. Sex-adjusted common ORs for simultaneous vaccination were 1.52 (0.45-5.21, p?=?0.71) for all vaccines, 1.83 (0.44-7.59, p?=?0.40) for inactivated vaccines only, and 1.36 (0.29-6.30, p?=?0.69) for mixed live and inactivated vaccines. In infants, these were 1.95 (0.44-8.72, p?=?0.38), 1.41 (0.29-6.94, p?=?0.67) and 2.85 (0.43-18.9, p?=?0.28), respectively. These limited data suggest no significant ITP risk following vaccinations or simultaneous vaccination in any age group, including infants.
Project description:Immunization programs currently measure coverage by assessing the proportion of children 12-24 months who have been immunized but this does not address the important question of when the scheduled vaccines were administered. Data capturing the timing of vaccination in first 6 months, when severe disease is most likely to occur, are limited.To estimate the time to Bacillus Calmette-Guérin (BCG) (recommended at birth), diphtheria-tetanus-pertussis-H, influenza b-hepatitis B (DTP-Hib-HepB), and oral polio vaccine (OPV) (recommended at 6, 10, and 14 weeks) vaccinations and risk factors for vaccination delay in infants <6 months of age in a district in southern Nepal where traditional coverage metrics are high.Infants enrolled in a randomized controlled trial of maternal influenza vaccination were visited weekly at home from birth through age 6 months to ascertain if any vaccinations had been given in the prior week. Infant, maternal, and household characteristics were recorded. BCG, DTP-Hib-HepB, and OPV vaccination coverage at 4 and 6 months was estimated. Time to vaccination was estimated through Kaplan-Meier curves; Cox-proportional hazards models were used to examine risk factors for delay for the first vaccine.The median age of BCG, first OPV and DTP-Hib-HepB receipt was 22, 21, and 18 weeks, respectively. Almost half of infants received no BCG by age 6 months. Only 8% and 7% of infants had received three doses of OPV and DTP-Hib-HepB, respectively, by age 6 months.A significant delay in receipt of infant vaccines was found in a prospective, population-based, cohort in southern Nepal despite traditional coverage metrics being high. Immunization programs should consider measuring time to receipt relative to the official schedule in order to maximize benefits for disease control and child health.
Project description:Compliance with recommended vaccinations for Indian infants is facilitated by using combination vaccines to minimize the number of required injections. The ready-to-use, preservative free, fully-liquid combination DTwP-HepB-Hib vaccine, Quinvaxem(®), offers convenience of administering five important vaccine antigens to infants in a single injection. This phase III, single-arm, multicenter study was designed to assess immunogenicity and safety of three doses of Quinvaxem(®) to Indian infants administered at 6, 10, and 14 weeks of age. Blood samples were taken prior to the first dose and at one month post last vaccination. Infants were observed clinically for any reaction approximately 30 min following each vaccination, and parents completed subject diaries for solicited local, systemic and any adverse events (AEs) following over a 5 d period. DTwP-HepB-Hib vaccine elicited strong immune responses that exceeded seroprotection/seroconversion thresholds against all vaccine antigens. At one month after third vaccination, percentages of infants achieving predefined protective antibody levels were 99% diphtheria; 100% tetanus; 98% Hepatitis B; 100% Hib short-term (? 0.15 µg/mL); 95% Hib long-term (? 1.0 µg/mL) protection; and relevant immune response was 99% for pertussis. The vaccine was well tolerated, with no vaccine-related serious AEs. Only one case of high fever (? 40 °C) was reported. The most frequently reported reactions were mild to moderate tenderness and erythema. Frequencies of all AEs declined with subsequent vaccinations. This study demonstrated that this convenient, fully-liquid DTwP-HepB-Hib vaccine is highly immunogenic and has a acceptable safety profile for use in Indian infants. ClinicalTrials.gov Identifier: NCT01470287. Clinical Trials Registry of India Number: CTRI/2011/11/002118.
Project description:Although public subsidies and physician recommendations for vaccination play key roles in increasing childhood vaccination coverage, the association between them remains uncertain. This study aimed to identify the association between awareness of public subsidies and recommendations for Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (pneumococcal conjugate vaccine (PCV)) and human papillomavirus (HPV) vaccinations among primary care physicians in Japan.This is a cross-sectional study.In 2012, a questionnaire was distributed among 3000 randomly selected physicians who were members of the Japan Primary Care Association.From the questionnaire, participants were limited to physicians who administered childhood vaccinations.The primary measures were participants' awareness of public subsidies and their recommendation levels for Hib, PCV and HPV vaccines. Multiple logistic regression analysis was performed to investigate the association between awareness and recommendation, with adjustment for possible confounders.The response rate was 25.8% (743/2880). Of 743 physician respondents, 434 were included as analysis subjects. The proportions of those who recommended vaccinations were 57.1% for Hib, 54.1% for PCV and 58.1% for HPV. For each vaccine, multivariable analyses showed physicians who were aware of the subsidy were more likely to recommend vaccination than those who were not aware: the adjusted ORs were 4.21 (95% CI 2.47 to 7.15) for Hib, 4.96 (95% CI 2.89 to 8.53) for PCV and 4.17 (95% CI 2.00 to 8.70) for HPV.Primary care physicians' awareness of public subsidies was found to be associated with their recommendations for the Hib, PCV and HPV vaccines. Provision of information about public subsidies to these physicians may increase their likelihood to recommend vaccination.
Project description:The aim of this study was to evaluate the long-term response to rituximab in patients with chronic and refractory immune thrombocytopenic purpura (ITP). Adults with ITP fail to respond to conventional therapies in almost 30% of cases, developing a refractory disease. Rituximab has been successfully used in these patients. We used rituximab at 375 mg/m2, IV, weekly for a total of four doses in 18 adult patients. Complete remission (CR) was considered if the platelet count was >100 x 10(9)/l, partial remission (PR) if platelets were >50 x 10(9)/l, minimal response (MR) if the platelet count was >30 x 10(9)/l and <50 x 10(9)/l, and no response if platelet count remained unchanged. Response was classified as sustained (SR) when it was stable for a minimum of 6 months. Median age was 43.5 years (range, 17 to 70). Median platelet count at baseline was 12.5 x 10(9)/l (range, 3.0 to 26.3). CR was achieved in five patients (28%), PR in five (28%), MR in four (22%), and two patients were classified as therapeutic failures (11%). Two additional patients were lost to follow-up. The median time between rituximab therapy and response was 14 weeks (range, 4 to 32). SR was achieved in 12 patients (67%). There were no severe adverse events during rituximab therapy. During follow-up (median, 26 months; range, 12 to 59), no other immunosuppressive drugs were used. In conclusion, rituximab therapy is effective and safe in adult patients with chronic and refractory ITP. Overall response rate achieved is high, long term, and with no risk of adverse events.
Project description:Persistent immune thrombocytopenia (ITP) patients require second-line treatments, for which information on clinical outcomes are lacking. A systematic review and network meta-analysis (NMA) were conducted. Only randomised controlled trials (RCT) of second-line drugs in adult persistent ITP patients with platelet response, platelet count, any bleeding or serious adverse events (SAE) outcome were eligible. Twelve RCTs (n = 1313) were included in NMA. For platelet response outcome, eltrombopag and romiplostin were the best relative to placebo; the former had a non-significant advantage [risk ratio (RR) = 1·10 (95% confidence interval: 0·46, 2·67)]. Both treatments were superior to rituximab and recombinant human thrombopoietin (rhTPO)+rituximab, with corresponding RRs of 4·56 (1·89, 10·96) and 4·18 (1·21, 14·49) for eltrombopag; 4·13 (1·56, 10·94) and 3·79 (1·02, 14·09) for romiplostim. For platelet count, romiplostim ranked highest, followed by eltrombopag, rhTPO+rituximab, and rituximab. For bleeding, rituximab had lowest risk, followed by eltrombopag and romiplostim. For SAEs, rhTPO+rituximab had highest risk, followed by rituximab, eltrombopag and romiplostim. From clustered ranking, romiplostim had the best balance between short-term efficacy and SAEs, followed by eltrombopag. In conclusion, romiplostim and eltrombopag may yield high efficacy and safety. Rituximab may not be beneficial due to lower efficacy and higher complications compared with the thrombopoietin receptor agonists. RCTs with long-term clinical outcomes are required.
Project description:Primary immune thrombocytopenia (ITP) is a disorder caused by autoantibody-mediated platelet destruction and decreased platelet production. Rituximab, a B cell-depleting agent, has become the first-line treatment for ITP; however, patients with refractory disease usually require splenectomy. We identified antibody-secreting cells as the major splenic B cell population that is resistant to rituximab. The phenotype, antibody specificity, and gene expression profile of these cells were characterized and compared to those of antibody-secreting cells from untreated ITP spleens and from healthy tissues. Antiplatelet-specific plasma cells (PC) were detected in the spleens of patients with ITP up to 6 months after rituximab treatment, and the PC population displayed a long-lived program similar to the one of bone marrow PC, thus explaining for most of these patients the absence of response to rituximab and the response to splenectomy. When analyzed by multiplex PCR at the single-cell level, normal splenic PC showed a markedly different gene expression profile, with an intermediate signature, including genes characteristic of both long-lived PC and proliferating plasmablasts. Surprisingly, long-lived PC were not detected in untreated ITP spleens. These results suggest that the milieu generated by B cell depletion promotes the differentiation and settlement of long-lived PC in the spleen.
Project description:New vaccines designed to prevent diseases endemic in low and middle-income countries (LMICs) are now being introduced without prior record of utilization in countries with robust pharmacovigilance systems. To address this deficit, our objective was to demonstrate feasibility of an international hospital-based network for the assessment of potential epidemiological associations between serious and rare adverse events and vaccines in any setting. This was done through a proof-of-concept evaluation of the risk of immune thrombocytopenic purpura (ITP) and aseptic meningitis (AM) following administration of the first dose of measles-mumps-containing vaccines using the self-controlled risk interval method in the primary analysis. The World Health Organization (WHO) selected 26 sentinel sites (49 hospitals) distributed in 16 countries of the six WHO regions. Incidence rate ratios (IRR) of 5.0 (95% CI: 2.5-9.7) for ITP following first dose of measles-containing vaccinations, and of 10.9 (95% CI: 4.2-27.8) for AM following mumps-containing vaccinations were found. The strain-specific analyses showed significantly elevated ITP risk for measles vaccines containing Schwarz (IRR: 20.7; 95% CI: 2.7-157.6), Edmonston-Zagreb (IRR: 11.1; 95% CI: 1.4-90.3), and Enders'Edmonston (IRR: 8.5; 95% CI: 1.9-38.1) strains. A significantly elevated AM risk for vaccines containing the Leningrad-Zagreb mumps strain (IRR: 10.8; 95% CI: 1.3-87.4) was also found. This proof-of-concept study has shown, for the first time, that an international hospital-based network for the investigation of rare vaccine adverse events, using common standardized procedures and with high participation of LMICs, is feasible, can produce reliable results, and has the potential to characterize differences in risk between vaccine strains. The completion of this network by adding large reference hospitals, particularly from tropical countries, and the systematic WHO-led implementation of this approach, should permit the rapid post-marketing evaluation of safety signals for serious and rare adverse events for new and existing vaccines in all settings, including LMICs.
Project description:This study investigated responses to retreatment with rituximab in chronic immune thrombocytopenic purpura (ITP) patients. Treatment with rituximab in chronic ITP patients induces long-lasting responses in approximately 30% of patients but even these patients may relapse. Twenty patients who had achieved a response to rituximab and relapsed were retreated with rituximab (375 mg/m(2)x 4); this data was analyzed retrospectively. Subsequently, 16 patients were prospectively randomized to receive rituximab with cyclophosphamide, vincristine and prednisone (R-CVP) or double dose rituximab (DDR). Retreatment with standard dose rituximab demonstrated responses similar to initial rituximab treatment in 15 of 20 patients. Neither of the two more intensive regimens (R-CVP, DDR) induced responses in any patient who had previously failed to respond to rituximab nor induced substantially longer-lasting responses among previous responders. No additional toxicity was noted with the DDR regimen, whereas R-CVP was not well tolerated. These results suggest that retreatment with standard dose rituximab induces similar responses in 75% of previously responding patients and is well tolerated. Neither combining rituximab with CVP nor doubling the dose of rituximab increased the response rate.