immunohistokemi för att avgöra om det kan vara en aktuell kandidat. I två studier visas en positiv korrelation (Brahmer et al., 2010, Patnaik et al., 2015). I den tredje studien där uttrycket undersöktes har förvisso 9 av de 25 patienter som bedömdes som positiva svarat på behandlingen, men de övriga 16 svarade inte (Topalian et al., 2012b). Dessa resultat är utförda på ett fåtal patienter och bör därför tolkas med försiktighet, vilket även nämns i studierna, men visar ändå på de motstridiga resultat som förekommer. Metaanalys har visat att överuttryck av PD-L1 är signifikant associerat med bättre svar på PD-1 eller PD-L1-blockad. Dock har ett signifikant antal patienter med väldigt lågt eller inget uttryck av PD-L1 också svarat på behandling (Meng et al., 2015). Resultaten i flera studier bör dock tolkas med försiktighet på grund av bristen på specificitet hos vissa kommersiellt tillgängliga antikroppar mot PD-L1, att enbart uttryck på ytan bör bedömas och svårigheten i att utveckla metoder för detektion i formalinfixerad och paraffininbäddad vävnad hävdar Sznol & Chen (Sznol & Chen, 2013). Andra problem med PD-L1 som biomarkör är att uttrycket av PD-L1 är dynamiskt så utvärdering vid en enskild tidpunkt säger inte så mycket om hur uttrycket kan utvecklas över tid. Uttrycket varierar även mellan primära tumörer och metastaser, även hos samma patient. Användandet av olika antikroppar och olika färgningstekniker kan ge olika resultat. Dessutom använder sig olika studier av olika gränsvärden för vad som ska bedömas som ett positivt uttryck (Meng et al., 2015). Trots bristerna är PD-L1 nog den mest välundersökta biomarkören och den är viktig med tanke på att samband setts. Behandling av icke-småcellig lungcancer med pembrolizumab ska bedömas efter just uttrycket av PD-L1 (Läkemedelsindustriföreningen, 2017a). Dock skulle mer forskning kring PD-L1 behöva utföras för att kunna avgöra om det är en bra biomarkör med tanke på att vissa som inte uttryckt liganden svarar på behandling och tvärtom. Undersökningar av vilken metod som är bäst för att bedöma uttrycket, vilken antikropp man ska använda sig av och om den bör baseras på flera snitt från olika tidpunkter behöver också utföras för att kunna avgöra om PD- L1 är den bästa biomarkören eller om bättre alternativ finns.
Images were centrally and jointly reviewed by two expe- rienced nuclear physicians who had no knowledge of the patients’ medical history or symptoms (LG and MS). We introduced the concept of an iPERCIST classification, adapted from PERCIST and iRECIST [8, 13]. The object- ive was to obtain a reliable tool for assessing the re- sponse to immunotherapy, taking into account the possible avid-FDG lymphocytic tumoral infiltration under treatment. As recommended in PERCIST, baseline and follow-up scans were reviewed, and the lesion with the highest FDG uptake on each of these two scans was identified . Complete metabolic response (CMR), partial metabolic response (PMR), and stable metabolic disease (SMD) were defined according to PERCIST . CMR was defined as the visual absence of pathological FDG uptake in all baseline lesions identified on the base- line PET scan. PMR was defined as a decrease of at least 30% in the SULpeak of the target lesion, which is associ- ated with an absence of progression of the non-target le- sions. SMD was defined as an absence of response or progression.
Several studies have demonstrated that blockingPD-1/ PD-L1 axis to overcome T cell exhaustion could strengthen GITR-targeted therapy. 57 Wang B et al have conducted single-cell RNA sequencing for over 2000 intratumoral CD8 + T cells in mouse after GITR and PD-1 antibodies administration and con ﬁ rmed that this combinatorial treat- ment synergistically improved CD8 + T cell function; PD-1 blockade restored the critical homeostatic regulators CD226 through inhibiting SHP-2 dephosphorylation of the CD226 intracellular domain, while GITR agonism weakened T cell ITIM domains and immunoreceptor with Ig expression. The combined treatment not only increased CD8 + T cell function but also generated proliferative Teff cells in CD226-dependent manner. 59 Synergistic therapy aimed at activating costimulatory receptor GITR and inhibiting PD-1 to generate robust T cell activation is being assessed in preclinical researches for metastatic melanoma and other solid tumors. 57,60 In these studies, GITR or PD-1-targeted monotherapy showed limited therapeutic effect and syner- gistic therapy could reactivate exhausted tumor-in ﬁ ltrating CD8 + T cells to induce long-term survival in breast and ovarian cancer mouse models. 61
Other potential biomarkers and combined biomarkers Alternative biomarkers, such as tumor etiology, the pres- ence or absence of TILs, composition of TIL effectors, circulating cytokine levels, neutrophil-to-lymphocyte ratio, and baseline and on-treatment immune effector composition, appear to correlate with antitumor activity and represent desirable predictors of responses to immunotherapy [97, 98]. Charoentong et al. revealed genotype–immunophenotype relationships in a pan-cancer immunogenomic analysis and developed a scoring scheme for the quantification, which was termed the immunophe- noscore, which predicts the response to PD-1 blockade . Strategies for combining two or more approaches of capturing the immune status of the tumor microenviron- ment may be more effective as a composite predictive bio- marker for the response to anti-PD-1 or anti-PD-L1 monotherapy . Even if the TIL density is low, high expression levels of PD-L1 can be detected in the tumor . Additionally, tumors with high TIL counts may not express PD-L1 . In these two cases, the clinical activity of anti-PD-1/L therapies may be low, but if the expression of PD-L1 or density of TILs alone is used as a biomarker, it may provide an inaccurately high prediction. In a phase I/II trial of 174 advanced HCC patients treated with nivolumab who could be evaluated for PD-L1 expression, objective responses were observed in 19% of 140 patients with PD- L1 <1 and 26% of 34 patients with PD-L1 ≥1% .There was no significant difference in the OS rate between groups based on the expression of PD-L1. One possible reason for these findings is that only the expression of PD-L1 was con- sidered in the trial, without considering the number of infiltrating TILs. If only PD-L1 is overexpressed without infiltration of cytotoxic T lymphocytes, immune checkpoint inhibitors are naturally ineffective toward such “cold tumors.” The combination of CD8 protein and PD-L1 expression may predict patients who will respond to nivo- lumab. Therefore, the combination of biomarkers is a potential research direction for clinical trials. The future development of an effective biomarker for predicting responses to anti-PD-1 or anti-PD-L1-based therapies will integrate multiple methods for optimal characterization of the immune tumor microenvironment.
The need for cross-priming in the antitumor immune response also indicates possible relationships with mechanisms of immunogenic tumor cell death ( 10 ). Recent results show a crucial role for BATF3-dependent CD103 + DCs in priming a CTL response through IL12 production in the context of tumor cell death induced with paclitaxel ( 12, 13 ). However, doxorubicin-mediated immunogenicity against F244 sarcoma cells is BATF3-independent ( 10 ), and BATF3-deﬁ cient mice are able to reject tumors under conditions with exogenously pro- vided IL12 ( 11 ). Therefore, the precise role of BATF3-dependent CD103 + DCs may depend on the context of the ongoing base- line immune response in the tumor, which will be eventually modulated by the treatment with immunostimulatory mAbs.
with virtually no significant changes in the last 30 years despite of the enormous number of drugs that have been investigated in these patients setting (1,2). In the last few years, cancerimmunotherapy has known an enthusiastic breakthrough because of the successful clinical development of monoclonal antibodies (mAbs) against programmed cell death receptor-1 (PD-1) (nivolumab and pembrolizumab) and PD-1 ligand-1 (PD-L1) (atezolizumab, avelumab and durvalumab) able to break immune tolerance related to PD-1/PD-L1 peripheral immune checkpoint (ICP) showing significant antitumor activity in a number of different malignant diseases including NSCLC, malignant melanoma, head and neck, urological and kidney cancer (3). Immune checkpoint blockade resulted very successful in the treatment of NSCLC patients where these mAbs alone or in combination with chemotherapy were associated to a significant benefit and outstanding response rate, progression-free survival (PFS) and overall survival (OS) (4). In light of this enthusiasm the possible use of immune checkpoint blockade with anti-PD-1/PD-L1 mAbs alone has been also tested in pretreated SCLC patients in several clinical trials showing a response rate lower than 20% and very limited efficacy in pretreated patients not bearing a high tumor mutation burden (5). More proficient results were achieved when central and peripheral immune checkpoint blockade combination strategy with anti- CTLA-4 and anti-PD-1 was adopted and associated to a 2-year OS rate greater than 30%. Unfortunately, also this strategy did not achieve sufficient scientific evidence to be approved as a standard treatment for SCLC patients (6). More recently, a randomized phase III trial (IMpower133) demonstrated a markedly prolonged PFS and OS when atezolizumab an anti-PD-L1 mAb was used in combination with carboplatin and etoposide. This regimen showed superiority over placebo plus etoposide and carboplatin (7) and was finally approved for the front-line treatment of these patients even though the response in term of either PFS and OS were very far from the outstanding results achieved in squamous and non-squamous NSCLC patients. In this context, the identification of potential strategies based on the use of immune checkpoint inhibitors alone or combinations in the treatment of SCLC patients remains challenging and requires further studies aimed to identify potential biomarker predictive of response and translational models to improve its efficacy. The starting point for these kinds of studies should be based on the knowledge of the mechanism of action of the different known immune checkpoints that are physiological instruments able
Data from a trial with another immunological agent have similarly suggested a possible benefit in patients with lower disease burden. A recently published study of ipilimumab in patients with mCRPC who were treated after palliative radiation and had progressed after doce- taxel did not meet its primary endpoint target of in- creased OS . However, in a retrospective subgroup analysis, this study suggested that a subpopulation with less advanced disease derived greater benefit from ipili- mumab compared to placebo . This subgroup con- sisted of patients with non-visceral disease, alkaline phosphatase less than 1.5 times the upper limit of nor- mal, and hemoglobin of 11 gm/dL or greater. For this subset, the median OS of patients treated with ipilimu- mab was 22.7 months compared with 15.8 months for the patients who received placebo. The median OS for patients with even one of the poor prognostic factors listed above was 6.5 months among those treated with ipilimumab and 7.3 months for those who received pla- cebo (p = 0.8756). However, we would underscore that to date there are no prospective data to support the use of CTLA-4 as a monotherapy for mCRPC. Similarly, in two phase I trials of nivolumab, an anti-PD-1 antibody, among 25 heavily pre-treated patients with prostate can- cer, there were no objective responses [26, 27]. Conse- quently, there are also no data to support the efficacy of checkpoint blockade with PD-1 or PD-L1 blockade as monotherapy in patients with advanced prostate cancer.
Bevacizumab is a humanized mAb that targets vascu- lar endothelial growth factor and became the third drug approved by the FDA for use in recurrent GBM in 2009 . However, the addition of bevacizumab to standard therapy in newly diagnosed glioblastoma patients has demonstrated no improvement in OS . The clinical responses of anti-VEGF treatment are transient; clinical relapse usually occurs within months after an initial re- sponse. By contrast, cancer immunotherapies can elicit durable and striking clinical activities . Thus, it is reasonable to assume that the combination of bevacizu- mab with immunotherapy is a favorable approach. In- deed, combined therapy using PD-1/PD-L1 axis blockade and anti-VEGF treatment has demonstrated encouraging antitumor activity and tolerable adverse events in some animal models and in clinical studies [56, 57]. There are also some crucial considerations to ac- count for in the development of targeted therapy and immunotherapy combinations, which include the optimization of dosing regimens and the minimization of treatment-related toxicities.
Checkpoint inhibitors display a range of response patterns, which may reflect the complexities of inducing a tumor-directed immune response and the individuality of a patient’s immune system and tumor. Response kinetics may also depend on which pathway is inhibited. In theory, a patient with extensive tumor infiltration of PD-1- expressing T cells could have a rapid response with a PD-1 pathway inhibitor. In contrast, a patient with low numbers of pre-existing tumor-specific T cells could have a delayed or no response to PD-1 or CTLA-4 pathway blockade. Late or delayed responses occurring months to years after treatment initiation have been described with checkpoint inhibitors [17, 38–40]. In the case of a delayed response, tumor size may initially increase—as a result of either true tumor growth or increased tumor volume due to infiltration by immune cells—prior to subsequent tumor regression. As such, PFS based on traditionally used response criteria, such as RECIST, may not be the most appropriate efficacy measure with immunotherapies. To guide clinical practice, expert opinion has suggested the use of modified response criteria for immunotherapies, termed immune-related response criteria (irRC). These response criteria take into account the potential for increase in tumor size or number of lesions prior to declaration of progressive disease (Table 2 [12, 17, 21, 38, 40–46]). It has been suggested that RECIST may underestimate the benefit of PD-1 inhibitors in approximately 10% of patients relative to irRC .
Kidney cancer (RCC) as well as urothelial cancer (UC) are highly immunogenic tumors. Advances in understanding cellular immunity have resulted in a new class of therapeutic agents. Anti-PD1 and anti-PD-L1 monoclonal antibodies are checkpoint inhibitors. They inhibit the immune response of PD1 on T cells (Treg) and PD-L1 on cancer cells. In metastatic or inoperable urothelial cancer, there is no effective second-line therapy, but checkpoint inhibitors have proved to be active and are increasingly being included in the guidelines for urothelial cancers. Numerous randomized phase II clinical trials are underway as well as adjuvant therapy for the efficacy of these substances . Nivolumab was evaluated for safety and activity in a study by Sharma et al. Patients with progression or relapse over 18 were enrolled in the phase II study. They had previously received at least one platinum-based treatment regimen. Patients received the drug intravenously at a dose of 3 mg/kg every 2 weeks, until disease progression, clinical deterioration, drug toxicity or other causes. The study showed that ORR was higher in patients with high PD-L1 expression (28.4% for PD-L1 ≥ 5%, 23.8% for PD-L1 ≥ 1% and 16.1% for PD-L1 <1 %), while the OS index was also higher for tumors with PD-L1 expression ≥1% vs. PD-L1 <1%. Nivolumab monotherapy provided significant clinical benefit and demonstrated an acceptable level of safety.[19,20]. In 2017, nivolumab as a drug for locally advanced or metastatic urothelial cancer was included in therapy by the FDA . The development of new targeted therapies and immunotherapy is a goal in the fight against kidney cancer. They are most often diagnosed accidentally, and 90% of kidney cancers are renal cell carcinoma, and as many as 17% of diagnosed patients have advanced stage of disease.
The identification of a selection marker for treatment, such as a BRAF mutation in melanoma, offers the ability to prospectively identify patients more likely to benefit from certain therapies. While ORRs with targeted therapies are high, not all patients are eligible. Initial evidence suggests that checkpoint inhibition may be more broadly applicable than targeted therapy. In trials of patients with melanoma being treated with checkpoint inhibitors, responses have been observed in patients with and without BRAF mutations, brain metastases, or prior treatment [12, 20, 40, 45, 57, 60]. As a potential biomarker of response, a rise in absolute lymphocyte count at 3, 7 or 12 weeks of ipilimumab treatment has been correlated with improved survival [61–64]. Studies have also shown a correlation between an increased eosinophil count—either at baseline or a rise between the second and third ipilimumab infusions—and improved survival [61, 65]. Also, an exploratory study found that pembrolizumab-treated patients with smaller baseline tumor size (≤ 90 mm) had higher responses and improved OS at 1 year as compared with patients with larger baseline tumors. However, patients with larger tumors also derived benefit from pembrolizumab . Predictors of toxicity are also being evaluated with checkpoint inhibitors. For example, IL-17 levels at 7 weeks of treatment with ipilimumab predicted colitis . Additionally, patients with a history of autoimmune disease may be more at risk for development of immunologic AEs with checkpoint inhibitors and were excluded from clinical trials [43, 50, 54].
BCG induction (6 weeks treatment) followed by 3 week maintenance BCG has significant beneficial impact on disease recurrence, progression, and out- comes, with superior results relative to chemotherapy . Several randomized trials have demonstrated this and are summarized in Kamat et al. . The final re- port from the study EORTC 98013, in which the dose (administered at three weekly instillations at months 3, 6, 12, 18, 24, 30, and 36 according to the SWOG schedule) and duration (1 year versus 3 years) of BCG maintenance were tested, demonstrated that full-dose BCG maintenance is more effective without added toxicities than the one-third dose at the same sched- ule. In addition, patients with high risk disease bene- fited from 3 years of maintenance . A recently completed Spanish Oncology Group (CUETO) study, in which the BCG maintenance therapy was modified to one instillation every 3 months, did not show a benefit of maintenance , and this has also been seen in a number of reports utilizing modified ap- proaches to maintenance BCG . Additionally, EORTC conducted a trial comparing BCG mainten- ance (SWOG schedule) to epirubicin maintenance and demonstrated significant superiority of BCG compared with epirubicin for all clinical parameters (time to first recurrence, time to distant metastases, and disease- specific as well as overall survival) in patients with both high and intermediate risk disease .
In this study, we investigated a study cohort of 383 gastric cancer patients in the TCGA database and 300 patients in the GEO cohort, and generated stromal scores using the ESTIMATE algorithm. Our results showed that the stromal score is a robust biomarker for predicting survival in GC and guiding more effective immunother- apy strategies. Patients in the low stromal score group have a survival advantage over those in the high stro- mal score group and would benefit more from anti-PD-1 therapy. Interestingly, this result is consistent with the finding that GC tumors classified as MSI, which is a rela- tively low stromal score subtype, show promising results for the use of PD-1/PD-L1 blockade [38–40]. In line with previous research , the high stromal score subtype showed activation of transforming growth factor and epi- thelial mesenchymal, which were considered T-cell sup- pressive [33–35] and to be involved with immunotherapy resistance.
Efforts are underway to combine multiple receptor tyrosine kinase inhibitors to prevent this emergence of resistance, but with these combinations come greater toxicities, which may limit their feasibility. In contrast, the ability of immunotherapy to target and eradicate micrometastatic disease is dependent on tumor cells’ protein expression. This makes it diffi cult for indi- vidual cells to overcome a potent immune response. Immune evasion can occur at a population level, with some cells that downregulate the expression of tar- gets or MHCs escaping elimination. Unlike the ad- ditional toxicity that is seen when multiple tyrosine kinase inhibitors are combined, additional epitopes can be easily included in cancer vaccines to reduce the chance of immune evasion.
recurrent/metastatic HNSCC. All the patients had PD-L1 expression in tumor cells of $1%, whereas 23 cases (38%) were HPV + and 37 cases (62%) were HPV - . Pembrolizumab (10 mg/kg body weight, intravenous [iv]) was administered once every 2 weeks for 24 months. Median duration of follow-up was 14 (interquartile range [IQR] 4–14) months. The overall response rate (ORR) was 18%, whereas the response rate of HPV + was 25% and that of HPV - was 14%. The median progression-free survival (PFS) was 2 months. The median overall survival (OS) was 13 months. Thirty- eight cases experienced treatment-related adverse events (63%), mainly fatigue, pruritus, nausea, reduced appetite, and rash. There were no treatment-related deaths.
In summary, currently the most commonly used predictive biomarker is PD-L1 expression assessed via IHC on tumor biopsies, although limitations are obviously present. Limitations such as heterogeneous expression, the role of expression outside of the tumor, and its dynamic expression during the disease process could be overcome by noninvasive molecular imaging using radiolabeled tracers that allow deep tumor penetration and repeated quantification of PD-1 and/or PD-L1 expression, which should enable mapping of primary tumors and metastatic lesions both before and during the treatment. Its potential as a tool to provide an accurate assessment of PD-1 and/or PD-L1 expression has been recently shown in preclinical studies, summarized in this review paper (Table 1).
Cardiac fibrosis induced by ipilimumab had been previ- ously examined by one of our groups  and thus prompted us to screen for cardiac side effects in check- point inhibitor therapy in six large cancer centers. We documented cases of autoimmune myocarditis, cardiomy- opathy, heart failure, cardiac fibrosis and cardiac arrest. Pre-existent cardiac pathology or peripheral arterial dis- ease was present in the majority of the patients (5 out of 8). Thus, possibly these cases present a worsening of pre- vious cardiac disorders. However, all of the patients were free of symptoms when starting checkpoint inhibitor ther- apy. Some of the pre-existent conditions had been stable for decades, i.e. a patient with myocardial infarction 20 years prior to initiating treatment. Corticosteroids im- proved symptoms when applied. Upon administration of corticosteroids, one patient experienced rapid improvement of ejection fraction that was severely reduced to 15 % due to autoimmune myocarditis. In 5 of the 8 patients (63 %) other organ systems were also affected by immune-related side effects including autoimmune thyroiditis, uveitis, col- itis, hepatitis and hypophysitis. It has previously been re- ported that two or more organ systems were affected in 7 % of patients treated with ipilimumab and in 31 % treated with the combination of ipilimumab and nivolumab (Hodi et al. ASCO 2015; Abstract 9004). Thus, special attention needs to be focused on patients who have already experi- enced one immune-related adverse event. There have been reports with increased response rates and median survival times in patients with irAE . In this case series, mean survival was 21 months with the patients surviving the se- vere side effects showing long-term survival.
This paper is a Focussed Research Review based on a presentation given at the Eighteenth International Conference on Progress in Vaccination against Cancer (PIVAC 18), held in Oslo, Norway, 3 rd – 5th October, 2018. It is part of a Cancer Immunology, Immunotherapy series of PIVAC 18 papers.
One of the primary consequences of deranged tumor cell metabolism is the generation of hypoxia. While exposure to hypoxia alone can have both positive and detrimental effects on T cell fate and function (24–26), hypoxia is certainly considered inhibitory to T cells in vivo (22, 27). Interestingly, transcriptional profiling tumors in anti–PD-1 responders versus nonresponders revealed a dominant hypoxia signature in immunotherapy-resistant patients (10, 23). Our data support previous work implicating hypoxia and hypoxic signaling in the metabolic and functional reprogramming of T cells (24–26), and suggest that hypoxia may divert differentiation into a dysfunctional exhausted phenotype rather than one associated with an effector-memory state. Further, we have previously shown in preclinical models that more oxidative tumors tend to be resistant to checkpoint blockade immunotherapy (16). Our data in nonresponders versus responders support the notion that tumor hypoxia correlates to resistance to anti–PD-1–based immuno- therapy. Some studies have previously suggested that it is the capacity of tumor cells to outcompete T cells for glucose that limits T cell function in the tumor microenvironment (9), and that cell lines derived from nonresponders to adoptive cell therapy were more glycolytic (11). Our study found no role for increased glucose metabolism in tumor cells or repressed T cell glucose uptake in the response to checkpoint blockade immunotherapy, and identifies oxygen as a key metabolite at the core of anti–PD-1immunotherapy sensi- tivity. Future studies will seek to determine whether adoptive cell therapies versus checkpoint blockade are metabolically distinct therapies, preferentially utilizing different fuel sources.
In the present study, we developed a novel biopanning strategy and discovered anti-PD-L1 peptide inhibitors (12 aa, ~ 1.6 kDa) to block the PD-1/PD-L1 interaction. The peptides exhibit high affinity and specificity to human PD- L1 protein as well as PD-L1-positive human cancer cells MDA-MB-231 and DU-145. Molecular docking studies indicate that the CLP002 peptide specifically binds to PD- L1 at the residues where PD-L1 interacts with PD-1. The peptide also blocks the CD80/PD-L1 interaction, which may further enhance the immune response of tumor- infiltrating T cells. The CLP002 peptide restores prolifera- tion and prevents apoptosis of T cells that are co-cultured with cancer cells. The CLP002 peptide also inhibits tumor growth and increases survival of CT26 tumor-bearing mice, suggesting that the CLP002 peptide represents a promising low-molecular-weight checkpoint inhibitor for cancerimmunotherapy.