Oslo University Hospital is sponsor of the study. We have established collaborations for patient recruitment with cancer centres in Australia, Denmark, Sweden and Spain. University of Western Australia is sponsor for the study in Australia. Patient recruitment started in June 2020 and is expected to finish by May 2022. Initiation of the trial was postponed due to the COVID-19 pandemic. By March 2021, patients are included in Norway, Australia and Denmark.
Objectives
Primary objective
To evaluate and compare the efficacy of nivolumab and ipilimumab with or without UV1-vaccine in patients with inoperable malignant pleural mesothelioma progressing after first-line platinum-based chemotherapy. The primary end point will be progression free survival (PFS) evaluated by modified response evaluation criteria in solid tumours (mRECIST) [11, 12] as determined by blinded, independent central review (BICR).
Secondary objectives
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To compare overall survival (OS), objective response rate (ORR), disease control rate (DCR), time to response (TTR) and duration of response (DOR) according to Response Evaluation Criteria in Solid Tumours, version 1.1 (Modified RECIST), in patients who receive nivolumab and ipilimumab with patients who receive nivolumab and ipilimumab in combination with UV1.
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To evaluate changes from baseline in patient-reported outcomes (PROs) of lung cancer symptoms, patient functioning, and health-related quality of life (HRQoL) in patients who receive nivolumab and ipilimumab compared to patients who receive nivolumab and ipilimumab in combination with UV1.
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To determine tolerability in patients who receive nivolumab and ipilimumab compared to patients who receive nivolumab and ipilimumab in combination with UV1.
Exploratory/translational objectives
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To characterise the TCR repertoire in patients receiving checkpoint inhibition alone compared with in combination with UV1 vaccination.
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To evaluate tumour mutational burden (TMB) as a predictive biomarker of response to therapy.
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To assess any difference in immune cell infiltration in tumour pre- and post-treatment with checkpoint inhibition alone or with UV1 vaccination.
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To assess vaccine-specific T-cell response in the blood cells of patients treated with UV1 vaccination.
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To assess any correlation between the microbial composition in faeces and treatment response.
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Evaluate dual-time PET as a predictive marker of therapy response and assess the ability of dual-time PET to distinguish between different cell types in the tumour.
Study design
This is a randomized, multi-centre, open-label, proof of concept study comparing the efficacy and safety of nivolumab and ipilimumab with or without UV1 in patients with inoperable malignant pleural mesothelioma after first-line platinum-based chemotherapy.
The patients (n = 118) will be randomized 1:1 into two treatment arms (see Fig. 1):
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A
Nivolumab and ipilimumab plus 8 UV1 vaccinations.
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B
Nivolumab and ipilimumab alone.
Treatment will be continued until disease progression, unacceptable toxicity or for a maximum of 2 years. Because of the potential for pseudo progression/tumour immune infiltration, this study will allow patients to remain on study treatment after apparent radiographic progression, provided the risk/benefit ratio is judged to be favourable.
Biological material will be sampled, and translational explorative analyses will be performed to identify biomarkers and reveal mechanisms of response and resistance
Dosage
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Nivolumab: 240 mg every 2 weeks for 2 years until progression or unacceptable toxicity.
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Ipilimumab: 1 mg/kg every 6 weeks for 2 years until progression or unacceptable toxicity.
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UV1 vaccination (arm A only): 8 intradermal injections with 300 μg UV1 and 75 μg GM-CSF (sargramostim) during the first 13 weeks. The first 3 UV1 vaccinations will begiven in week 1, one in week 2, followed by four UV1 vaccinations throughout the following 11 weeks, totalling eight vaccinations. The first three vaccinations of UV1 will be given prior to the first infusion of nivolumab and ipilimumab.
Overview of the study procedures and treatment can be found in Table 1.
Table 1 Overview of study treatment and procedures Rationale for the choice of vaccine
Telomerase activation is a major factor contributing to cancer proliferation, immortality, and invasiveness [13,14,15], and its activation is documented in MPM [16, 17]. Tumour telomerase expression is correlated with poor outcome for many cancers [18,19,20], conversely, spontaneously occurring telomerase-directed CD4+ T-cell responses have recently been identified as a positive prognostic factor in NSLCL [21], substantiating its relevance as a target for vaccination in thoracic malignancies. Vaccination with UV1 induces immune responses directed at telomerase reverse transcriptase (hTERT), the catalytic subunit of the telomerase complex. By targeting this essential cancer protein, there are limited possibilities for resistance mutations to develop, as loss of hTERT would restrict tumour proliferation and metastasis. Furthermore, by mounting a CD4+ Th1 response (i.e. secretion of IFN-γ, TNFα and IL-2), the vaccine aims to induce an inflammatory tumour microenvironment to further stimulate the expansion of secondary effector cells. UV1 is administered with granulocyte-macrophage colony-stimulating factor (GM-CSF) as an adjuvant. The safety and immunological response of the vaccine given as monotherapy have been investigated in two clinical phase I/II trials [22, 23]. The combination of the UV1 vaccine with ipilimumab in metastatic malignant melanoma patients has been investigated in a phase I/IIa trial (n = 12) (Aamdal E. et al. Manus in prep.) (NCT02275416). Together, these studies have shown that UV1 is generally safe and well tolerated. Common adverse events related to UV1 include pruritus, erythema, fatigue, diarrhoea, pain and rash. Overall, six of the 52 patients vaccinated with UV1 (12%) experienced serious adverse events that were related to UV1 and/or GM-CSF, of these five were of allergic origin. All events resolved without sequelae.
Across the three phase I/II-studies conducted with UV1, vaccine-specific immune responses were observed in 78% (range 67–91%) of patients across the different cancer types (and HLA allele types), supporting the universality of the vaccine. Survival time for patients who responded immunologically was longer than for patients who did not respond immunologically to the vaccine, and survival time correlated with the breadth of the vaccine-specific immune response.
In summary, UV1 is safe alone and in combination with checkpoint inhibitors and trials in other cancers show that UV1 induces vaccine-specific immune response associated with survival.
Rationale for the choice of immunotherapy
The rationale for combining UV1 vaccination with immune checkpoint inhibitors is for the vaccine to prime a meaningful T cell response that can be enhanced by the checkpoint inhibitors to facilitate the activity of the tumour-specific T cells in the tumour microenvironment. Several pre-clinical studies have shown improved anti-tumour responses upon combination of vaccine and checkpoint inhibitors [24]. Data from clinical studies combining anti-immune checkpoint blockade and vaccines are still limited, but some early trials show encouraging results and were recently reviewed [25]. PD-1 and CTLA-4 checkpoints differentially affect CD8+ and CD4+ T-cell phenotypes [26] and recent data indicate that immune responses induced by anti-CTLA-4 and anti-PD-1 checkpoint-blockade are driven by different cellular mechanisms [27]. This indicates that vaccination with long peptides containing both CD4 and CD8 T-cell epitopes combined with both ipilimumab and nivolumab could be expected to have a maximal synergistic effect.
UV1-specific immune responses were induced in 11 out of 12 melanoma-patients treated with UV1 vaccine in combination with ipilimumab. The immune response appeared more frequently and rapidly than in patients treated with UV1 alone [22], [23] (Aamdal et al. manuscript submitted), suggesting a synergistic effect of blocking of CTLA-4 and vaccination with UV1. Of 12 patients, one patient developed a complete response, three patients obtained a partial response, and two achieved stable disease as best overall response. The safety, clinical and immunological responses of the UV1 vaccine when used in combination with the PD-1 immune checkpoint inhibitor pembrolizumab is currently under investigation in a phase I/II clinical trial in patients (N = 30) with metastatic malignant melanoma (NCT03538314).
In summary, ipilimumab and nivolumab has shown clinical benefit in patients with MPM and trials in other tumour groups have found immunological synergy between ipilimumab and UV1.
Patient selection
Selected inclusion and exclusion criteria are shown in Table 2.
Table 2 Selected inclusion and exclusion criteria Safety measures
Handling of toxicities
Administration of study treatment will be performed in a setting with emergency medical facilities and staff who are trained to monitor for and respond to medical emergencies. All adverse events and serious adverse events will be recorded during the trial and for up to 30 days after the last dose of study drug or until the initiation of another anti-cancer therapy, whichever occurs first. After this period, investigators should report serious adverse events and adverse events of special interest that are believed to be related to prior treatment with study drug. Events will be graded according to NCI CTCAE v5.0.
Dose reduction considerations (selected points)
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Dose reduction of nivolumab or ipilimumab is not permitted, apart from changing the dosing intervals for ipilimumab to every 12th week.
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For any concomitant conditions already apparent at baseline, the dose modifications will apply according to the corresponding shift in toxicity grade, if the investigator feels it is appropriate. For example, if a patient has grade 1 asthenia at baseline that increases to grade 2 during treatment, this will be considered a shift of one grade and treated as grade 1 toxicity for dose-modification purposes.
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When several toxicities with different grades of severity occur at the same time, the dose modifications should be according to the highest grade observed.
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If, in the opinion of the investigator, a toxicity is considered to be due to some component of the treatment leading to a dose delay, the other component(s) may be administered if there is no contraindication.
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If a patient experiences a grade 3 or 4 adverse event considered probably related to ipilimumab, the ipilimumab dosing interval should be extended to every 12 weeks. The ipilimumab dose should be kept at 1mg/kg.
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Patients may temporarily suspend study treatment with nivolumab/ipilimumab if they experience an adverse event that requires a dose to be held.
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If nivolumab is held because of adverse events for > 42 days (6 weeks), the patient will be discontinued from nivolumab treatment.
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If ipilimumab is held because of adverse events for > 126 days (18 weeks), the patient will be discontinued from nivolumab treatment.
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If the patient is likely to benefit from resuming nivolumab/ipilimumab after a longer hold than allowed (6 or 18 weeks), the study drug may be restarted with the approval of the Sponsor. If a patient must be tapered off steroids used to treat adverse events, nivolumab may be held for > 42 days until steroids are discontinued or reduced to prednisone dose equivalent ≤ 10 mg/day.
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The treating physician may use discretion in modifying or accelerating the dose modification guidelines described depending on the severity of toxicity and an assessment of the risk versus benefit for the patient, with the goal of maximizing patient compliance and access to supportive care.
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Dose modification of GM-CSF (sargramostim) or UV1 is not allowed in this study. If ipilimumab and nivolumab are withheld during the study treatment period, UV1 vaccination must also be withheld. UV1 vaccinations will only be reintroduced if both ipilimumab and nivolumab are reintroduced.
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UV1 vaccination and/or ipilimumab and nivolumab not administered will not be replaced during the study treatment period.
Independent data monitoring
An independent data monitoring committee (IDMC) has pre-planned assessment of the safety of the trial 4 and 13 weeks after the first 6 and 14 patients have started treatment. All the IDMC assessments has been successfully completed.
Sample collection/biobanking
An extensive research program will be conducted. The patient informed consent form will allow for performing biomarker analyses, immunological studies, gene profiling and studies of tumour evolution/heterogeneity during treatment, as well as comparison with data/material from other studies.
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(1)
Tumour biopsies collected pre, during and post therapy (time of progression). If sufficient tissue is available, three biopsies will be obtained at each timepoint, and prioritized in the following order:
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(a)
FFPE tissue.
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(b)
Snap-frozen tumour biopsies.
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(c)
Fresh tumour cells/tumour infiltrating lymphocytes frozen as cell suspension (selected sites).
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(2)
A separate biopsy (snap-frozen) will be taken at week 6 from those patients who consent to the procedures.
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(3)
Blood samples collected pre-, during and post-therapy:
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(a)
Peripheral blood mononuclear cells, processed with gradient centrifugation and frozen on liquid nitrogen (selected sites).
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(b)
Plasma/serum, separated and frozen.
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(c)
Circulating tumour cells (only if sufficient resources available).
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(4)
Urine samples collected pre-, during and post-therapy.
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(5)
Faecal samples collected at baseline, tumour evaluation timepoints and progression.
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(6)
Dual-time PET analyses at baseline, 6 weeks, 1 year and at progression (selected sites).
Statistical analyses
Under the null hypothesis, the PFS hazard ratio (HR), for ipilimumab and nivolumab in combination with UV1 (ipi/nivo/UV1) vs ipilimumab and nivolumab (ipi/nivo) is assumed to be 1.00. Under the alternative hypothesis, the HR is assumed to be 0.60. To test the null hypothesis with 80% power and a 1-sided alpha level of 0.10, a total of 69 PFS events are required. Based on the INITIATE trial [28], with 12 months median follow-up it is expected that 69% of patients treated with ipi/nivo will have progressed and, with a HR of 0.60, it is further expected that 51% of patients treated with ipi/nivo/UV1 will have progressed. With an expected accrual rate of 5 patients per month, a total N=118 patients randomized into the trial over a 24-month period and followed for a minimum of 2–3 months after the last patient is randomized will yield the 69 PFS events required.