Abstract
Objective: To evaluate immune responses in fingolimod-treated patients with multiple sclerosis (MS) against influenza vaccine (to test for responses against anticipated novel antigens in seronegative patients) and recall (tetanus toxoid [TT] booster dose) antigens.
Methods: This was a blinded, randomized, multicenter, placebo-controlled study. Patients aged 18 to 55 years with relapsing MS were randomized (2:1) to fingolimod 0.5 mg or placebo for 12 weeks. At week 6, patients received seasonal influenza vaccine (containing antigens of California, Perth, and Brisbane virus strains) and TT booster dose. Antibody titers against influenza and TT were estimated at baseline (prevaccination) and 3 and 6 weeks postvaccination. The primary efficacy variable was responder rate (proportion of patients showing seroconversion or significant increase [≥4-fold] in antibody titers against at least one influenza virus strain) at 3 weeks postvaccination and vs placebo.
Results: Of 138 randomized patients (fingolimod 95, placebo 43), 136 completed the study (2 discontinued in fingolimod group). The responder rates (odds ratio; 95% confidence interval) for influenza vaccine (fingolimod vs placebo) were 54% vs 85% (0.21; 0.08–0.54) at 3 weeks and 43% vs 75% (0.25; 0.11–0.57) at 6 weeks postvaccination. For TT, responder rates were 40% vs 61% (0.43; 0.20–0.92) at 3 weeks and 38% vs 49% (0.62; 0.29–1.33) at 6 weeks postvaccination. Adverse events were reported in 86.3% and 79.1% of patients receiving fingolimod and placebo, respectively.
Conclusion: Most fingolimod-treated patients with MS were able to mount immune responses against novel and recall antigens and the majority met regulatory criteria indicating seroprotection. However, response rates were reduced compared with placebo-treated patients. This should be kept in mind when vaccinating patients on fingolimod.
Classification of evidence: This study provides Class I evidence that in some patients with MS receiving immunizations, concurrent fingolimod treatment in comparison to placebo decreases vaccination-induced immune responses.
GLOSSARY
- CCR7=
- C-C chemokine receptor 7;
- CI=
- confidence interval;
- HAI=
- hemagglutination inhibition;
- Ig=
- immunoglobulin;
- KLH=
- keyhole limpet hemocyanin;
- MS=
- multiple sclerosis;
- OR=
- odds ratio;
- PPV-23=
- 23-valent pneumococcal polysaccharides vaccine;
- S1P=
- sphingosine 1-phosphate;
- TT=
- tetanus toxoid
Fingolimod (FTY720; Gilenya, Novartis Pharma AG, Basel, Switzerland) is a first-in-class sphingosine 1-phosphate (S1P) receptor modulator1 approved as 0.5-mg once-daily oral therapy for relapsing multiple sclerosis (MS) in 70 countries, including the United States, Japan, and the European Union.2 Modulation of S1P receptors by fingolimod results in inhibition of S1P receptor-1–dependent lymphocyte egress from lymph nodes.3 The recirculation of lymphocytes, which presumably also contain autoreactive lymphocytes, is therefore reduced, preventing migration of autoreactive lymphocytes into the CNS.4,–,6 However, fingolimod has a differential effect on T-cell subsets, preferentially retaining C-C chemokine receptor 7 (CCR7)-positive naive and central memory T cells, while sparing CCR7-negative effector memory T cells.7 The preferential effect of fingolimod on T cells may, despite reduction in the peripheral lymphocyte count, account for unchanged infection rates in individuals treated with fingolimod when compared with placebo.1,7,–,9 In a study in healthy volunteers, fingolimod 0.5 mg had a mild to moderate inhibitory effect on the capacity of the immune system to respond to T-cell–dependent (keyhole limpet hemocyanin [KLH]) and T-cell–independent (23-valent pneumococcal polysaccharides vaccine [PPV-23]) novel antigen, demonstrating that subjects retained capacity to mount a clinically relevant immune response.10 A smaller study in patients with MS demonstrated that fingolimod-treated patients can mount an antigen-specific adaptive immune response that is comparable with the response observed in healthy volunteers.11 The current study amends the findings of previous studies by providing Class I evidence on the immune response against anticipated novel antigen (first seasonal influenza vaccine with the 2010 H1N1 pandemic flu strain) and recall antigen (tetanus toxoid [TT] booster dose) in patients with MS treated with fingolimod compared with placebo.
METHODS
Standard protocol approvals, registrations, and patient consents.
The study was registered with ClinicalTrials.gov (identifier NCT01199861) and conducted in accordance with Good Clinical Practice and the ethical principles of the Declaration of Helsinki. The ethics committees and institutional review boards of all participating centers (26 centers in 9 countries) approved the study protocols. All participants provided written informed consent.
Study design.
Our study aim was to provide Class I evidence whether in patients with MS receiving immunizations, concurrent fingolimod treatment in comparison to placebo affects vaccination-induced immune responses against novel and recall antigens. This was a 12-week, blinded, randomized, multicenter, placebo-controlled, parallel-group, 2-arm, phase 3b study. After screening and baseline assessments, eligible patients were randomly assigned (2:1) to receive either fingolimod 0.5 mg or placebo. After 6 weeks, single doses of seasonal influenza vaccine and TT booster dose were administered to all patients. Antibody titers were estimated at baseline (prevaccination) and 3 and 6 weeks postvaccination (9 and 12 weeks after randomization). Patients were recruited between August 2010 and December 2010 and were subsequently vaccinated between September 2010 and January 2011. A full list of sites and investigators is provided in the supplemental material on the Neurology® Web site at Neurology.org.
Patients.
Eligible patients were men and women aged 18 to 55 years, diagnosed with relapsing forms of MS according to the revised McDonald criteria (2005),12 with an Expanded Disability Status Scale score of 0 to 6.5, and who had received lifetime TT vaccination. Patients were excluded if they had a history of vaccination with 2010/2011 northern hemisphere seasonal influenza vaccine or planned to receive this vaccination outside the study, history of influenza disease 6 months before screening, H1N1 vaccination or confirmed or suspected H1N1 influenza infection within 3 months before randomization, history of TT vaccination within 1 year before randomization, received or expected to receive any live-attenuated vaccines, history of serious reaction or allergy after administration of any vaccine, history of chronic disease with a known immunodeficiency, macular edema, malignancy, negative varicella-zoster virus immunoglobulin (Ig)G antibodies, treatment with immunosuppressive drugs, or clinically significant cardiovascular conditions and systemic diseases.
Interventions.
Fingolimod 0.5-mg capsules and matching placebo were administered orally once daily. The first dose was administered as per-protocol under the supervision of the investigator, preferably before noon to allow time for adequate monitoring. Patients were vaccinated with injectable 2010/2011 seasonal influenza vaccine (Agrippal, Novartis Vaccines, Basel, Switzerland), containing antigens of California, Brisbane, and Perth strains, and TT booster dose (Tetanol, Novartis Vaccines). In countries where Agrippal and Tetanol were not approved, vaccines approved for use in those individual countries were used. Eighty-four patients (55 in fingolimod and 29 in placebo group) were given other influenza vaccine and 105 patients (71 in fingolimod and 34 in placebo group) were given other TT vaccine. All vaccines were administered according to the manufacturer label.
Randomization and blinding.
Eligible patients were randomized to fingolimod or placebo treatment arms by using validated interactive voice response or an interactive Web response system. The randomization sequence was generated in balanced block sizes of 6. The study medications were identical in packaging, labeling, schedule of administration, appearance, and odor. Patients and investigators were blinded; however, for logistical reasons, the investigator, study staff, and Novartis personnel had access to some potentially unblinding information, for example, 6-hour first-dose monitoring data and lymphocyte levels. Central laboratory personnel measuring antibody titers were different from those measuring lymphocyte counts and were blinded to the lymphocyte counts.
Assessments.
Antibody titers against influenza vaccine were measured by hemagglutination inhibition (HAI) antibody titer (hemagglutination test) and against TT (anti-TT titers) by ELISA. The immune responses were determined by the change in antibody titers between prevaccination and postvaccination time points.
The primary efficacy variable was responder rate to the seasonal influenza vaccine 3 weeks postvaccination. Secondary efficacy variables were responder rates to influenza vaccine 6 weeks postvaccination, responder rates to the TT booster dose 3 weeks and 6 weeks postvaccination, and inhibition of immune response to each strain (California, Brisbane, and Perth) within the influenza vaccine and to TT booster dose. The 3-week time point was chosen in accordance with the European Medicines Agency guidance for the timing for testing of immunogenicity of flu vaccines13; the 6-week time point was scheduled at the study end. To limit exposure of patients with MS to placebo, the overall study duration was limited to 3 months.
Other efficacy criteria14 were seroprotection, seroconversion of seronegative patients, significant increase in antibody titer in seropositive patients, and inhibition of immune response. These criteria were defined as follows. Seroprotection (attaining postvaccination antibody levels that fulfill a 50% probability of clinical protection if exposed to infection)15 was defined as a postvaccination HAI antibody titer of ≥1:40 or anti-TT antibody titer of ≥0.4 IU/mL. A significant increase in antibody titer was defined as an increase in prevaccination to postvaccination antibody titer by ≥4-fold, in which the prevaccination HAI and anti-TT antibody titer was ≥1:10 and ≥0.1 IU/mL. Responder rate was defined as the proportion of patients showing seroconversion or a significant increase (≥4-fold) in antibody titer from prevaccination to postvaccination for at least 1 of the 3 strains contained in the seasonal influenza vaccine or TT booster dose. Similarly, a post hoc sensitivity analysis was also performed for both vaccines in which antibody titers were assessed based on the “2-fold rule” (≥2-fold increase in antibody titers). Inhibition of immune response was defined as 1 minus the ratio between treatment median of the post- and prevaccination geometric mean antibody titers. The treatment difference was expressed as the relative inhibition of an immune response caused by fingolimod compared with placebo.
Exploratory efficacy variables were seroprotection, seroconversion, significant increase in antibody titer against seasonal influenza vaccination and TT booster dose, and geometric mean antibody titers pre- and postvaccination.
Safety evaluations consisted of adverse events, serious adverse events, hematology and blood chemistry (assessed at a central laboratory), vital signs, physical examinations, optical coherence tomography, ECGs, and first-dose monitoring. During first-dose monitoring, heart rate and blood pressure were monitored hourly for 6 hours.
Statistical considerations.
The main focus was on estimating and describing a potential treatment effect of fingolimod on the immune response compared with placebo, rather than on hypothesis testing. With a total sample size of 102 completers (68 on fingolimod and 34 on placebo), and with sufficient precision, the 95% confidence interval (CI) for a between-treatment difference (odds ratio [OR]) would exclude one, assuming responder rates of 60% and 80% to the influenza vaccine in fingolimod and placebo groups (OR = 0.375). Allowing for a dropout or unevaluable rate of 15%, 120 patients were planned to be randomized in a 2:1 ratio to fingolimod and placebo groups. Assuming a screen failure rate of 10%, approximately 135 patients were expected to be screened for this trial.
All randomized patients (the full analysis set) were included for the efficacy analyses. Data were analyzed according to the treatment the patients were assigned at randomization. The efficacy variables were analyzed using a logistic regression model with treatment and region as factors. Responder rates were calculated by treatment group, and the potential treatment effect was presented as an OR and corresponding 95% CI. Summary for the seroconversion and significant increase of antibody titers to each seasonal influenza strain and TT booster dose were presented by visit and treatment group. Inhibition of immune response was log-transformed and analyzed in a 2-way analysis of covariance (ANCOVA) model. Least square means and corresponding 95% CI for the log-transformed post- and prevaccination ratio were calculated by treatment arm. The back-transformed point estimates were referred to as geometric mean antibody titer ratios. All patients who received study medication were included in the safety analyses. Safety assessments were summarized by treatment group.
Classification of level of evidence.
This study provides Class I evidence that in some patients with MS immunizations, concurrent fingolimod treatment in comparison to placebo decreases vaccination-induced immune responses. The study assessed the immune response to novel and recall antigens in fingolimod-treated patients with MS compared with placebo in a blinded, randomized, multicenter international trial. The patients with MS receiving fingolimod treatment mounted a reduced immune response against both novel and recall antigens (responder rate ≥54% and 40%, respectively) compared with placebo (responder rate 85% and 61%, respectively) at 3 weeks postvaccination.
RESULTS
Patients.
One hundred thirty-eight patients (95 in fingolimod and 43 in placebo group) were randomized in the study (figure 1). Patient demographics, baseline disease characteristics, and antibody titers were comparable between the fingolimod and placebo groups (table 1). The majority of patients had a prevaccination antibody titer of ≥1:10 against the California (>60%) and Brisbane (>90%) strains. Approximately 7% of patients had a prevaccination antibody titer of ≥1:40 against the California strain and 33% against the Brisbane strain. However, for the Perth strain, most patients (≥93%) had a prevaccination antibody titer of >1:40. The prevaccination anti-TT titer levels were similar in both treatment groups: >75% of patients had titer of ≥0.1 IU/mL and >60% had ≥0.4 IU/mL.
Patient demographics and baseline disease characteristics
Responder rate.
The responder rates for influenza vaccine and TT booster dose at 3 and 6 weeks postvaccination are presented in figure 2. The responder rates for influenza vaccine in the fingolimod vs placebo group were 54% vs 85% at 3 weeks (OR 0.21; 95% CI 0.08–0.54) and 43% vs 75% at 6 weeks (OR 0.25; 95% CI 0.11–0.57) postvaccination. Similarly, for TT booster dose, responder rates in the fingolimod vs placebo were 40% vs 61% at 3 weeks (OR 0.43; 95% CI 0.20–0.92) and 38% vs 49% at 6 weeks (OR 0.62; 95% CI 0.29–1.33) postvaccination.
N′ is the number of patients in the full analysis set with nonmissing measurement at that visit and an appropriate baseline value. CI = confidence interval.
The proportion of patients who met the criteria for seroprotection, seroconversion, and significant increase in antibody titer for influenza vaccine and TT booster dose at 3 and 6 weeks postvaccination are presented in table 2.
Percentage of patients showing seroprotection, seroconversion, or a significant increase in antibody titer at 3 and 6 weeks after vaccination to seasonal influenza vaccine strains and TT booster dose
In a post hoc sensitivity analysis, the responder rates, based on 2-fold increase in antibody titers for influenza vaccine were 82% and 95% for fingolimod and placebo (OR 0.23; 95% CI 0.05–1.04) at 3 weeks and 74% and 96% (OR 0.13; 95% CI 0.03–0.59) at 6 weeks postvaccination. The responder rates for TT booster dose in the fingolimod and placebo groups were 57% and 75% (OR 0.45; 95% CI 0.20–1.00) at 3 weeks postvaccination and 56% and 70% (OR 0.54; 95% CI 0.25–1.18) at 6 weeks postvaccination.
Inhibition of immune response.
The geometric mean antibody titers prevaccination and postvaccination (3 weeks and 6 weeks) are presented in figure 3. The geometric mean antibody titer ratio for fingolimod vs placebo was 0.59 (95% CI 0.39–0.90) for the California strain, 1.35 (95% CI 0.88–2.08) for the Perth strain, and 0.56 (95% CI 0.42–0.74) for the Brisbane strain. The percent inhibition of immune response by fingolimod treatment at 3 weeks postvaccination was 41% for the California strain and 44% for the Brisbane strain. The geometric mean antibody titer ratio for fingolimod vs placebo was 0.65 (95% CI 0.41–1.04) 3 weeks postvaccination and the percentage of inhibition of immune response to TT was 35%. Similarly, at 6 weeks after vaccination, the percent inhibition of immune response was 38% for the California strain, 48% for Brisbane strain, and 27% for TT booster dose.
Perth strain: prevaccination antibody titer of ≥1:10 in all patients, geometric mean titers ≥600 ng/mL in both treatment groups.
Safety and tolerability.
There were no new safety or tolerability signals for fingolimod in this study. The seasonal influenza vaccination and TT booster dose were well tolerated in patients with MS treated with fingolimod.
DISCUSSION
The key finding of our study is that fingolimod-treated patients with MS can in principle mount immune responses against both seasonal influenza vaccine (novel antigen in previously seronegative patients) and TT booster dose (recall antigen); however, there was a clearly lower immune response compared with placebo. A lower proportion of patients in the fingolimod group showed seroconversion or a significant increase from baseline (≥4-fold) in antibody titers against seasonal influenza vaccine (California and Brisbane strains) both at 3 weeks and 6 weeks after vaccination. There was a clearly reduced immune response with fingolimod compared with placebo against 2 influenza strains, the California and the Brisbane strain. The Perth strain results could not be evaluated for immune response because of high baseline (prevaccination) antibody titers, which precluded a significant increase, as well as the high proportion of seroprotected patients. For TT booster dose, again a considerably smaller proportion of patients in the fingolimod group compared with placebo showed significant increase (≥4-fold) in anti-TT titer at 3 and 6 weeks after vaccination. Of note, a markedly higher proportion of patients showed seroconversion at 6 weeks after vaccination. Immune response to TT booster dose showed that treatment with fingolimod did not significantly affect the recall immune response.
In a post hoc sensitivity analysis considering a ≥2-fold increase in antibody titers against influenza vaccine and TT booster dose, the difference in the immune responses in fingolimod and placebo groups at both 3 and 6 weeks postvaccination was less pronounced. The ≥2-fold increase in antibody titers is a frequently used measure when assessing vaccine response,16–18 and was used in the previous fingolimod trial assessing antibody responses to antigen in healthy volunteers.10 Assessment of immune response by the more conservative ≥4-fold increases in antibody titers in this study was based on regulatory guidelines for vaccine clinical trials.
Although fingolimod acts by sequestering pathologic CCR7-positive T cells that presumably contain autoreactive T cells such as Th17 cells and reduces peripheral lymphocyte counts (to 20%–30% of baseline values), these results demonstrate that patients can in principle mount primary and memory immune responses.19 In clinical trials, reported rates of overall infection in patients treated with fingolimod were similar to those of patients receiving placebo irrespective of lymphocyte count.20 It is nonetheless recommended to avoid live attenuated vaccines during and for 2 months after treatment with fingolimod because of the potential risk of infection.
Two previous vaccination studies10,11 have also shown that subjects treated with fingolimod were able to trigger antigen-specific immune responses. One study in healthy volunteers showed that fingolimod 0.5 mg once daily for up to 4 weeks caused a mild to moderate decrease in T-cell–dependent and –independent antibody responses to novel antigens (KLH and PPV-23).10 In the second study, vaccine-specific adaptive immune response was found to be comparable in fingolimod-treated patients with MS and healthy controls.11 The proportion of individuals fulfilling seroprotection criteria after influenza vaccination was similar in fingolimod-treated patients and healthy controls, and remained increased at days 14 and 28 postvaccination in both groups.11 Increases in the number of influenza-specific T cells and in the concentrations of anti-influenza antibody IgM and IgG after vaccination were also similar in both groups.11 Of note, in this exploratory study, concentrations of influenza-specific Igs were determined by the use of an ELISA with plate-bound antigens whereas the HAI assay used in our study reflects the functional properties of anti-influenza Igs. Finding decreased influenza HAI antibody titers may indicate that fingolimod qualitatively affects humoral immune responses. This is in principle compatible with findings from animal models in which fingolimod reduced the formation of germinal centers for B-cell responses. Against the background of a potential relevance of humoral autoimmunity in the pathogenesis of MS, this may contribute to the beneficial effects of fingolimod.
The fact that in this study, immune response was not evoked as strongly as anticipated may be attributed to the high antibody titer that the majority of patients already had at baseline for the Perth strain, as well as for other strains. In fact, two-thirds of patients were already seropositive for the California and Brisbane strains, and only 30% of patients had the possibility to seroconvert.
The geometric mean IgG antibody titers for the California and Brisbane strains and TT booster dose as well as the respective responder rates increased 3 weeks after vaccination and then declined at 6 weeks after vaccination in both fingolimod and placebo groups. The decrease of antibody titers that occurred in both, patients receiving fingolimod and those receiving placebo, is well compatible with the observation that peak antibody levels are regularly reached within 4 to 6 weeks after influenza vaccination.21 Antibody titers were not determined beyond 6 weeks after vaccination, which is a limitation of the study. Another limitation of our study was that vaccine-specific T-cell responses were not assessed and therefore could not be correlated with humoral vaccine-induced immune responses.
Although fewer fingolimod- than placebo-treated patients reached the criteria for response, more than 40% of patients in the fingolimod treatment group showed a significant increase in antibody titers (≥4--fold) or seroconversion compared with baseline for both the California strain and the Brisbane strain thus fulfilling the European Medicines Agency criteria for the immunogenicity of influenza vaccines.13 In both treatment groups, the majority of patients (>90%) achieved seroprotection after the TT booster dose.
The results of our study provide Class I evidence that fingolimod treatment is compatible with mounting an effective immune response after vaccinations with novel and recall antigens, but that this response is markedly reduced in some patients compared with placebo. This should be considered when vaccinating patients.
AUTHOR CONTRIBUTIONS
L. Kappos, M. Mehling, R. Arroyo, G. Izquierdo, K. Selmaj, V. Curovic-Perisic, A. Keil, and P. von Rosenstiel designed and conceptualized the study, and analyzed and interpreted the data. M. Bijarnia designed the study and performed the statistical analysis. A. Singh drafted and revised the manuscript. All authors had full access to the data and the statistical analysis, and reviewed and provided input on the final version of the article.
STUDY FUNDING
Funded by Novartis Pharma AG, Basel, Switzerland.
DISCLOSURE
L. Kappos has received institutional research support as compensation for serving as a member of advisory boards or steering committees, or as a consultant or speaker, from the following companies: Actelion Pharmaceuticals Ltd., Advancell, Allozyne, BaroFold, Inc., Bayer HealthCare Pharmaceuticals, Bayer Schering Pharma, Bayhill Therapeutics, Biogen Idec, BioMarin Pharmaceutical Inc., CSL Behring, Elan Corporation, Genmab, GenMark Diagnostics, GeNeuro SA, GlaxoSmithKline, Lilly, MediciNova, Merck Serono, Mitsubishi, Novartis, Novo Nordisk, Peptimmune, Sanofi, Santhera Pharmaceuticals, Roche, Teva Pharmaceutical Industries Ltd., UCB, Wyeth, the Swiss MS Society, the Swiss National Research Foundation, the European Union, and the Gianni Rubatto, Novartis, and Roche Research Foundations. M. Mehling reports receiving research support from the Swiss Multiple Sclerosis Society. R. Arroyo served as a consultant to and has received honoraria from Teva Pharmaceutical, as well as other pharmaceutical companies that market drugs for the treatment of patients with multiple sclerosis and other medical conditions. G. Izquierdo serves on the scientific advisory boards for Biogen Idec, Bayer Schering Pharma, Sanofi-Aventis, Novartis, Merck Serono, and Teva Pharmaceutical Industries Ltd. K. Selmaj received honoraria for consultation and invited talks from Novartis, Biogen Idec, Merck Serono, Roche, ONO Pharmaceuticals, and Genzyme. V. Curovic-Perisic is an employee of Novartis. A. Keil is an employee of Novartis. M. Bijarnia is an employee of Novartis. A. Singh is an employee of Novartis. P. von Rosenstiel is an employee of Novartis. Go to Neurology.org for full disclosures.
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Editorial, page 864
Supplemental data at Neurology.org
- Received January 21, 2014.
- Accepted in final form October 13, 2014.
- © 2015 American Academy of Neurology
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