Therapeutic vaccination with TNF-Kinoid in TNF antagonist-resistant rheumatoid arthritis: a phase II randomized, controlled clinical trial

Abstract

Objectives: Active immunization, or vaccination, with tumor necrosis factor (TNF)-Kinoid (TNF-K) is a novel approach to induce polyclonal anti-TNF antibodies in immune-mediated inflammatory diseases. This study was performed to transfer the proof of concept obtained in mice model of rheumatoid arthritis (RA) into human. We designed a pilot study to demonstrate the feasibility of therapeutic vaccination in RA.

Methods: This was a phase IIa, placebo-controlled, multicenter study in adults with RA who previously experienced secondary failure of TNF antagonists. Patients were immunized intramuscularly with 2 or 3 doses of placebo (n = 10) or 90 (n = 6), 180 (n = 12), or 360 µg TNF-K (n = 12). The primary objective was to identify the best dose and schedule based on anti-TNF antibody titers. Clinical symptoms and safety were assessed during 12 months and solicited reactions for 7 days after each injection.

Results: The highest anti-TNF antibody response was detected in patients immunized with 360 µg TNF-K and with 3 injections, although this difference was not significant with all other groups. Similar proportions of patients receiving TNF-K and placebo reported adverse events up to month 12. Serious adverse events were reported by 4 patients treated with TNF-K (13.3%) and 3 treated with placebo (30.0%), all unrelated to treatment. At month 12, DAS28-CRP, tender and swollen joint counts, and HAQ scores decreased significantly more in patients who exhibited anti-TNF antibody response than in patients who did not.

Conclusions: TNF-K therapeutic vaccination induced dose- and schedule-dependent anti-TNF antibodies in RA patients and was well tolerated. Patients who developed anti-TNF antibodies showed a trend toward clinical improvement. Although the most aggressive dose and schedule, i.e. 360 mg dose administered 3 times, did show a strong trend of higher antibody response, further studies are warranted to examine even higher and more frequent doses in order to establish the best conditions for clinical improvement.

Trial registration: ClinicalTrials.gov NCT01040715.

Conflict of interest statement

Competing Interests: PV OD BF SO GGV are employees of Neovacs SA and own stock or stock options in Neovacs SA. Data collection and management was subcontracted to a CRO, Inferential (35 rue Godot de Mauroy, 75009 Paris, France). Inferential had a role in the data analysis of the manuscript. Inferential had no role in the study design, decision to publish, or preparation of the manuscript. All this work was GCP compliant. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data.

Figures

Figure 1. Study design.

In the first stage, 8 patients were randomized 3∶1 to receive 90 µg TNF-K or placebo, in the second, 16 patients were randomized 3∶1 to receive 180 µg TNF-K or placebo, and in the third, 17 patients were randomized 3∶1 to receive 360 µg TNF-K or placebo. In each stage, patients were also randomized 1∶1 to receive 2 doses (day 0, 28) or 3 doses (day 0, 7, 28) (arrows). For stages 1 and 2, after 3 patients had been enrolled and no safety issues had been reported for at least 7 days, enrolment in the subsequent stage started in parallel. One patient randomized to receive 3 doses of 360 µg TNF-K withdrew consent prior to treatment. The principal analysis portion of the study continued up to day 84, and the follow-up portion continued up to month 12.

Figure 2. Humoral immune response to TNF.

Patients were treated with 2 doses (days 0 and 28) or 3 doses (days 0, 7, and 28) of placebo or 90, 180, or 360 µg TNF-K. Anti-TNF antibody titers were determined by enzyme-linked immunosorbent assay. (A) GMTs. (B) Percent of patients in each treatment group with detectable anti-TNF antibodies (titer ≥200) up to month 3 (at study day 38, 56, or 84), at month 6, at month 12, or at any time up to month 12 (i.e., antibody responders).

Figure 3. T cell response to TNF.

Peripheral blood mononuclear cells were collected on days 0 and 56 and treated in vitro with medium (control) or with 10 µg/mL TNF-K, TNF, or KLH. Lymphoproliferation was assessed after 72 h by 3H-thymidine incorporation. Shown is the stimulation index (fold-increase in lymphoproliferation vs. control) for cells from patients treated with placebo (n = 6) or TNF-K (n = 10).

Figure 4. Difference from baseline for clinical assessments in anti-TNF antibody responders and non-responders.

Post-hoc analyses: Mean changes in clinical assessments from baseline are shown at months 3, 6, and 12 for antibody responders (detectable anti-TNF antibodies at any time; gray bars) and for non-responders (white bars). (A) DAS28-CRP. (B) CRP. (C) Tender joints count. (D) Swollen joints count. (E) Patient’s global activity score. (F) Physician’s global activity score. (G) Patient assessment of pain. (H) Change in HAQ disability/function score. Error bars indicate standard error of the mean. P-values were determined by Wilcoxon rank-sum test. NS, not significant (p≥0.05). In responders, n = 19 at month 3, 16 at months 6 and 12 except at month 3 for Physician GAS n = 18 and for CRP n = 20. In non-responders, n = 17 at month 3 and 15 at months 6 and 12 except at month 6 n = 14 for CRP and DAS 28 score.