‘DURVIT’: a phase-I trial of single low-dose durvalumab (Medi4736) IntraTumourally injected in cervical cancer: safety, toxicity and effect on the primary tumour- and lymph node microenvironment

Cervical cancer is the fourth most common cancer in women worldwide and is caused by a persistent infection with high-risk human papilloma virus (HPV) types [1, 2]. The highest incidence of cervical cancer lies between 35 and 45 years of age [3]. Although vaccines to prevent cervical cancer are widely implemented, advanced stage cervical cancer is still an important cause of mortality among women worldwide [4].

The most important prognostic factor in early stage cervical cancer is the presence of metastatic tumour cells in the pelvic lymph nodes [5]. After radical hysterectomy and pelvic lymphadenectomy, women with early stage cervical cancer with negative lymph nodes have a 5-year survival rate of 80–90%, compared to a 5-year survival of 60–65% for patients with one lymph node metastasis [6, 7]. Adjuvant treatment in patients with lymph node metastasis and/or other risk factors is (chemo)radiation [8, 9]. However, adjuvant chemoradiation is associated with increased morbidity (with reported symptoms such as nausea, pain, vaginal tightness and urinary complaints) and impaired quality of life [10]. Of note, adjuvant (chemo)radiation in cervical cancer may also result in ovarian failure, and most patients diagnosed with cervical cancer are relatively young [11].

To improve the prognosis and quality of life of cervical cancer patients, novel adjuvant treatments are urgently needed. A highly promising area of research focuses on lifting tumour-induced immune suppression. Cancer cells employ various mechanisms to evade immune-mediated surveillance and elimination, which allows them to develop and spread unchecked. One of these strategies comprises upregulation of proteins on the cell surface that deliver inhibitory signals to cytotoxic T cells, the so-called immune checkpoints. Programmed cell death ligand 1 (PD-L1) is an example of such an immune checkpoint, and is upregulated in a broad range of cancers, including lung [12], renal cell [13‐15], pancreatic [16‐18], ovarian cancer [19] and hematologic malignancies [20, 21].

Several studies have reported on the upregulation of PD-L1 and/or PD-1 in cervical carcinoma and surrounding inflammatory cells [22‐25]. Recently, we performed a retrospective study on primary tumours (n = 205) and paired metastatic lymph nodes (n = 127) from cervical cancer patients and showed PD-L1 expression by primary tumour cells as well as by tumour infiltrating and stromal CD163+ positive M2 macrophages [26]. In 54% of all squamous cell primary tumours (SCC) and in 14% of all adenocarcinomas (AC) PD-L1 positivity was observed in > 5% of the tumour cells. PD-L1 expression in tumour margins (i.e. at the tumour/stroma interphase) in SCC was related to favourable survival and most likely induced by IFNγ released by adjacent activated T cells. In SCC, diffuse PD-L1 expression was associated with poor prognosis as was the presence of PD-L1 positive macrophages in AC. Furthermore, we reported on the high and interrelated rates of PD-L1 positive myeloid cells and regulatory T cells (Tregs) in metastatic lymph nodes in patients with cervical cancer [27]. In a comparative study of the immune status of all dissected cervical tumour-draining lymph nodes in five patients, we described that immunosuppression (identified as low CD8+ T cell/ FoxP3+ Treg ratios) may precede actual metastasis, creating niches in the tumour-draining lymphatic catchment area [28]. These results led to the hypothesis that tumour-associated PD-L1 positive macrophages expand Tregs which subsequently migrate to down-stream lymph nodes to create immune suppressed metastatic niches [29].

These studies support the clinical exploration of immunotherapies aimed at counteracting the immunosuppressive microenvironment in the primary tumour and the tumour-draining lymph nodes by PD-1/PD-L1 checkpoint blockade. By facilitating a robust antitumour T cell response, immune therapy can break the cycle of immune suppression and metastatic spread.

Durvalumab is a human monoclonal antibody (mAb) of the immunoglobulin G1 kappa (IgG1κ) subclass that blocks binding of PD-L1 to PD-1 and CD80 (B7–1). To date, results of several trials with systemically administered durvalumab in patients with advanced or metastatic cancer show promising antitumour activity with durable responses [30]. Durvalumab was recently approved by the U.S. Food and Drug Administration for patients with locally advanced or metastatic urothelial carcinoma who have disease progression during or following platinum-containing chemotherapy [31].

The systemic treatment with PD-1 and PD-L1 inhibitors can cause severe autoimmune side effects [32]. In the current study durvalumab is administered locally, i.e. in the cervix. As cervical cancer initially metastasizes through regional lymph nodes, we believe that local administration of durvalumab at an early stage will deliver these antibodies exactly where they are needed. Our hypothesis is that local conditioning of the tumour and tumour draining lymph nodes (TDLN) in the neo-adjuvant setting will lead to both loco-regional and systemic immune activation.In this way, undesirable systemic side effects may be avoided. Additional interest in local administration of checkpoint inhibitors is raised by the fact that the locally administered medication is expected to be (systemically) effective at a lower dose, leading to a desirable decline in the expenses involved.

With a peak incidence between 35 and 45 years of age, patients diagnosed with cervical cancer are relatively young. In early stage cervical cancer, the percentage of relapses is 5% to 40% depending on lymph node metastasis and other risk factors [35]. The most common types of cervical cancer are squamous cell carcinoma (SCC) and adenocarcinoma (AC), which are known to be mostly HPV-16 and HPV-18 positive, respectively [36, 37]. We have previously reported on the expression of PD-L1 in SCC and AC [26]. Intratumoural injection of anti-PD-L1, in this case durvalumab, with the aim to specifically modulate the loco-regional environment is an innovative clinical approach for the treatment of cervical cancer. Evidence of safety and biological efficacy of this strategy will contribute to the design of novel adjuvant therapy options for cervical cancer patients. In this way early metastatic spread to the draining lymph node basin, and beyond, may be controlled and thereby the onset of disease recurrence may be delayed or even prevented.

Although blocking the PD-1/PD-L1 axis has been associated with improved survival in many cancer types, auto immune-related side effects are often reported (in up to 70% of patients) [38]. These findings are based on studies including patients with advanced stages of disease. In studies evaluating the safety of intravenous anti-PD-L1 in patients with different types of cancer, most reported side effects were fatigue, infusion reactions, rash, arthralgia, pruritus, diarrhoea and decreased appetite. Immune-related adverse events included rash, hypothyroidism and hepatitis [39, 40]. Local administration of low-dose checkpoint inhibitors may reduce these side effects.

Until now, there is only one study that has reported interim results on the effect of systemic anti-PD-1 or PD-L1 treatment in cervical cancer. Data show that pembrolizumab, an anti-PD-1 antibody, can have durable antitumour activity in patients with PD-L1-positive advanced cervical cancer [41]. The safety profile was consistent with that seen in other tumour types. Out of 24 treated patients there were 2 discontinuations due to grade 3 treatment-related AEs and no ≥ grade 4 treatment-related AEs were reported. Currently, several trials are in progress testing systemic anti-PD-1 or PD-L1 treatment in cervical cancer [42]. However, none of these trials concern the local administration of therapy.

We have recently obtained promising results in early-stage melanoma patients receiving a single low dose of the anti-CTLA4 checkpoint inhibitor tremelimumab. Low Treg frequencies were seen in the draining sentinel lymph node (compared to historic saline placebo controls) as well as post-treatment reduced systemic rates of activated Tregs in peripheral blood. Simultaneously, tumour-specific, NY-ESO-1 reactive effector-T cell frequencies were increased in the peripheral blood. Of note, apart from one mild case of vitiligo, no serious side effects were observed [van Pul et al., manuscript in preparation]. Furthermore, in 2016 Ray et al. reported that intratumourally injected IL-2 and ipilimumab (anti CTLA-4) in patients with non-resectable melanoma was well tolerated. Antitumour responses were detected in the injected lesions, as well as an abscopal effect was observed [43]. In general, anti-CTLA4 checkpoint inhibitors have more immune related adverse events than antibodies blocking PD-1 or PD-L1 [38].

Encouragingly, similar local immune potentiation of the primary melanoma excision site and the sentinel lymph node with the Toll-like receptor-9 ligand CpG-B in two randomized phase II trials of early-stage patients with melanoma led to activation of dendritic cell subsets. Tumour-specific T cell expansion at the injection site, in the draining sentinel lymph nodes and peripheral blood was detected [44, 45] Moreover, significantly increased recurrence-free survival rates were observed [46].

Since patients will be given a single and low dose of durvalumab, we do not expect any treatment related SAEs exceeding grade 3. We anticipate that the side effects of local administration of durvalumab may include:

For the first time in cervical cancer, intratumoural administration of an immune checkpoint inhibitor will be investigated primarily for safety. We believe we will also be able as an exploratory objective, to unravel in a quantitative and qualitative manner the effect of the PD-L1 inhibitor durvalumab on the microenvironment in the primary tumour, the tumour draining lymph nodes and, importantly, on the systemic immune response. The proposed correlative immunoassays will shed light on mechanisms underlying the biological effects of PD-L1 blockade and may demonstrate its biological efficacy. These tests will aid in the selection of optimal dose and target population for subsequent studies, and facilitate a rational approach to the design of later phase 2 trials of this novel immunotherapy strategy.