Releasing the restraints of Vγ9Vδ2 T-cells in cancer immunotherapy

Objectives

Vγ9Vδ2 T-cells are a subset of T-cells with a crucial role in immunosurveillance which can be activated and expanded by multiple means to stimulate effector responses. Little is known about the expression of checkpoint molecules on this cell population and whether the ligation of these molecules can regulate their activity. The aim of this study was to assess the expression of both activatory and inhibitory receptors on Vγ9Vδ2 T-cells to assess potential avenues of regulation to target with immunotherapy.

Methods

Expression of various activatory and inhibitory receptors was assessed on Vγ9Vδ2 T-cells by flow cytometry following activation and expansion using zoledronic acid (ZA) and Bacillus Calmette-Guérin (BCG). Expression of these markers and production of effector molecules was also examined following co-culture with various tumour cell targets. The effect of immune checkpoint blockade on Vγ9Vδ2 T-cells was also explored.

Results

Vγ9Vδ2 T-cells expressed high levels of activatory markers both at baseline and following stimulation. Vγ9Vδ2 T-cells expressed variable levels of inhibitory checkpoint receptors with many being upregulated following stimulation. Expression of these markers is further modulated upon co-culture with tumour cells with changes reflecting activation and effector functions. Despite their high expression of inhibitory receptors when cultured with tumour cells expressing cognate ligands there was no effect on Vδ2+ T-cell cytotoxic capacity or cytokine production with immune checkpoint blockade.

Conclusions

Our work suggests the expression of checkpoint receptors present on Vγ9Vδ2 T-cells which may provide a mechanism with the potential to be utilised by tumour cells to subvert Vγ9Vδ2 T-cell cytotoxicity. This work suggests important candidates for blockade by ICI therapy in order to increase the successful use of Vγ9Vδ2 T-cells in immunotherapy.

Bacillus Calmette-Guerin (BCG) induces superior anti-tumour responses by Vδ2+ T cells compared with the aminobisphosphonate drug zoledronic acid

Vδ2⁺ T cells can recognize malignantly transformed cells as well as those infected with mycobacteria. This cross-reactivity supports the idea of using mycobacteria to manipulate Vδ2⁺ T cells in cancer immunotherapy. To date, therapeutic interventions using Vδ2⁺ T cells in cancer have involved expanding these cells in or ex vivo using zoledronic acid (ZA). Here, we show that the mycobacterium Bacillus Calmette–Guérin (BCG) also causes Vδ2⁺ T-cell expansion in vitro and that resulting Vδ2⁺ cell populations are cytotoxic toward tumour cell lines. We show that both ZA and BCG-expanded Vδ2+ cells effectively killed both Daudi and THP-1 cells. THP-1 cell killing by both ZA and BCG-expanded Vδ2+ cells was enhanced by treatment of targets cells with ZA. Although no difference in cytotoxic activity between ZA- and BCG-expanded Vδ2+ cells was observed, BCG-expanded cells degranulated more and produced a more diverse range of cytokines upon tumour cell recognition compared to ZA-expanded cells. ZA-expanded Vδ2+ cells were shown to upregulate exhaustion marker CD57 to a greater extent than BCG-expanded Vδ2+ cells. Furthermore, ZA expansion was associated with upregulation of inhibitory markers PD-1 and TIM3 in a dose-dependent manner whereas PD-1 expression was not increased following expansion using BCG. Intradermal BCG vaccination of rhesus macaques caused in vivo expansion of Vδ2⁺ cells. In combination with the aforementioned in vitro data, this finding suggests that BCG treatment could induce expansion of Vδ2⁺ T cells with enhanced anti-tumour potential compared to ZA treatment and that either ZA or BCG could be used intratumourally as a means to potentiate stronger anti-tumour Vδ2⁺ T-cell responses.

Abstract 2691: Expression pattern and prognostic significance of HER family members and EGFRvIII in pancreatic cancer

Pancreatic cancer is one of the most aggressive, heterogeneous, and fatal types of human cancers. There is urgent need for discovery of biomarkers of prognostic significance, predictive value and as well as therapeutic targets in patients with pancreatic cancer. In this study, we examined the relative expression and prognostic significance of all HER family members and the type III EGFR mutant (EGFRvIII) in patients with pancreatic ductal adenocarcinoma (PDC). The expression levels of wild-type EGFR (wtEGFR), HER2, HER3, HER4 and EGFRvIII were determined in tumor specimens from 43 patients by immunohistochemistry using antibodies DAK-H1-WT, Neu 3B5, SP71, HFR1 and NBP2-50599 respectively. The staining was scored based on the percentage of positive tumor cells, the intensity (i.e. strong 3+, moderate 2+, weak 1+) and the cellular location of immunostaining (i.e. membranous, cytoplasmic or nuclear). The association between the expression level of the biomarkers and patient overall survival was evaluated using Chi-squared, Kaplan-Meier survival curves and log rank test. At cut-off value of above 5%, we found weak to moderate expression of wtEGFR, HER2, HER3, HER4 and EGFRvIII in 4.7%, 14%, 14%, 20.9% and 2.3% of the cases examined respectively. The cellular location of wtEGFR and HER2 was found to be predominantly cytoplasmic, HER-3 membranous and cytoplasmic whereas HER4 expression was found to be mainly nuclear. There was no statistically significant association between the expression level of these markers and patient overall survival. The expression levels of the above biomarkers were also evaluated in tissue microarrays (TMAs) from 40 cases of pancreatic ductal adenocarcinoma. Interestingly, at the same cut-off value, 62.5%, 75%, 0%, 55% and 5% of the TMAs were positive for wtEGFR, HER2, HER3, HER4 and EGFRvIII respectively. Overall, we found that the expression pattern of HER family members was heterogenous, and with EGFRvIII expression being very low in both whole tumor sections and TMAs from patients with pancreatic cancer. Taken together, our results provide support for more detailed studies of co-expression of all HER family members in a larger group of pancreatic cancer patients. Such studies should help to unravel their potential as targets for therapeutic interventions as well as their prognostic significance and predictive value for response to therapy.

Citation Format: Tanzeel Khan, Said A. Khelwatty, Izhar Bagwan, Alan Seddon, Angus Dalgleish, Satvinder Mudan, Helmout Modjtahedi. Expression pattern and prognostic significance of HER family members and EGFRvIII in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2691.

Adjuvant bevacizumab for melanoma patients at high risk of recurrence: survival analysis of the AVAST-M trial

Background

Bevacizumab is a recombinant humanised monoclonal antibody to vascular endothelial growth factor shown to improve survival in advanced solid cancers. We evaluated the role of adjuvant bevacizumab in melanoma patients at high risk of recurrence.

Patients and methods

Patients with resected AJCC stage IIB, IIC and III cutaneous melanoma were randomised to receive either adjuvant bevacizumab (7.5 mg/kg i.v. 3 weekly for 1 year) or standard observation. The primary end point was detection of an 8% difference in 5-year overall survival (OS) rate; secondary end points included disease-free interval (DFI) and distant metastasis-free interval (DMFI). Tumour and blood were analysed for prognostic and predictive markers.

Results

Patients (n=1343) recruited between 2007 and 2012 were predominantly stage III (73%), with median age 56 years (range 18–88 years). With 6.4-year median follow-up, 515 (38%) patients had died [254 (38%) bevacizumab; 261 (39%) observation]; 707 (53%) patients had disease recurrence [336 (50%) bevacizumab, 371 (55%) observation]. OS at 5 years was 64% for both groups [hazard ratio (HR) 0.98; 95% confidence interval (CI) 0.82–1.16, P = 0.78). At 5 years, 51% were disease free on bevacizumab versus 45% on observation (HR 0.85; 95% CI 0.74–0.99, P = 0.03), 58% were distant metastasis free on bevacizumab versus 54% on observation (HR 0.91; 95% CI 0.78–1.07, P = 0.25). Forty four percent of 682 melanomas assessed had a BRAF^V600 mutation. In the observation arm, BRAF mutant patients had a trend towards poorer OS compared with BRAF wild-type patients (P = 0.06). BRAF mutation positivity trended towards better OS with bevacizumab (P = 0.21).

Conclusions

Adjuvant bevacizumab after resection of high-risk melanoma improves DFI, but not OS. BRAF mutation status may predict for poorer OS untreated and potential benefit from bevacizumab.

Clinical Trial Information

ISRCTN 81261306; EudraCT Number: 2006-005505-64

Report of Objective Clinical Responses of Cancer Patients to Pharmaceutical-grade Synthetic Cannabidiol

BACKGROUND/AIM

Cannabinoids are widely used in the management of pain, nausea and cachexia in cancer patients. However, there has been no objective clinical evidence of any anticancer activity yet. The aim of this study was to assess the effects of pharmaceutical-grade synthetic cannabidiol on a range of cancer patients.

PATIENTS AND METHODS

We analysed the data routinely collected, as part of our treatment program, in 119 cancer patients over a four-year period.

RESULTS

Clinical responses were seen in 92% of the 119 cases with solid tumours including a reduction in circulating tumour cells in many cases and in other cases, a reduction in tumour size, as shown by repeat scans. No side-effects of any kind were observed when using pharmaceutical grade synthetic cannabidiol.

CONCLUSION

Pharmaceutical-grade synthetic cannabidiol is a candidate for treating breast cancer and glioma patients.

Abstract 5758: Generation and characterization of novel monoclonal antibodies against overexpressed CD109 on pancreatic cancer cells for use in diagnosis and therapy

Pancreatic cancer is one of the most aggressive and lethal types of cancer, and more effective therapeutic agents are urgently needed. Overexpressed cell surface antigens are ideal targets for therapy with monoclonal antibody (mAb)-based drugs, and several have been approved for the treatment of human cancers; however, none have approval for pancreatic cancer. Our aim was to discover novel overexpressed cell surface antigens in human pancreatic cancer cells using mAb technology. We have generated two novel mouse mAbs, KU42.33C and KU43.13A, against the human pancreatic cancer cell line BxPC-3. Using ELISA, flow cytometry, competitive assay and mass spectrometry, we discover that these two mAbs target two distinct epitopes on the external domain of CD109 that are overexpressed by varying amounts in human pancreatic cancer cell lines. Treatment with these two naked antibodies alone did not affect tumor cell growth in vitro or cell migration. Of the two mAbs, only KU42.33C was useful in determining the expression of CD109 in tumor cells by Western blot and immunohistochemistry. Immunohistochemistry of human pancreatic carcinoma arrays with mAb KU42.33C showed that 94% of the 65 human pancreatic adenocarcinoma cases were CD109 positive, with no expression in normal pancreatic tissues. Our results suggest that these two novel mAbs are excellent tools for determining the expression level of CD109 in the tumor specimens and sera of patients with a wide range of cancers, in particular pancreatic cancer, and for investigating its diagnostic, prognostic and predictive value. Further research should unravel the therapeutic potential of the humanized forms or the conjugated versions of such antibodies in patients whose tumors overexpress CD109 antigen.

Citation Format: Gustavo A. Arias-Pinilla, Angus Dalgleish, Satvinder Mudan, Izhar Bagwan, Tony Walker, Helmout Modjtahedi. Generation and characterization of novel monoclonal antibodies against overexpressed CD109 on pancreatic cancer cells for use in diagnosis and therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5758.

An approach for automatic classification of grouper vocalizations with passive acoustic monitoring

Grouper, a family of marine fishes, produce distinct vocalizations associated with their reproductive behavior during spawning aggregation. These low frequencies sounds (50-350 Hz) consist of a series of pulses repeated at a variable rate. In this paper, an approach is presented for automatic classification of grouper vocalizations from ambient sounds recorded in situ with fixed hydrophones based on weighted features and sparse classifier. Group sounds were labeled initially by humans for training and testing various feature extraction and classification methods. In the feature extraction phase, four types of features were used to extract features of sounds produced by groupers. Once the sound features were extracted, three types of representative classifiers were applied to categorize the species that produced these sounds. Experimental results showed that the overall percentage of identification using the best combination of the selected feature extractor weighted mel frequency cepstral coefficients and sparse classifier achieved 82.7% accuracy. The proposed algorithm has been implemented in an autonomous platform (wave glider) for real-time detection and classification of group vocalizations.

Case report on the role of radiofrequency-assisted spleen-preserving surgery for splenic metastasis in the era of check-point inhibitors

RATIONALE

An isolated splenic metastasis is a rare phenomenon noted in advanced stage melanoma. We report the role of radiofrequency (RF) -based splenic-preserving splenectomy in a patient with a solitary splenic metastasis from advanced stage melanoma that was managed with checkpoint inhibitors.

PATIENT CONCERNS

We report a case of a 60-year-old man who presented with multiple lung metastases and a solitary splenic metastasis with advanced stage melanoma following excision of primary from his trunk 2.3 years back.

DIAGNOSIS

Considering the diagnosis of advanced stage melanoma with multiple lung metastases and a solitary splenic metastasis, and its ongoing progressive nature. This case was discussed in the tumour board meeting.

INTERVENTIONS

A decision was made to commence treatment with immunotherapy in the form of PD-1 inhibitor (programmed cell death 1 receptor) pembrolizumab. Follow-up restaging computer tomography (CT) scan of the abdomen and chest showed a significant reduction in the lung and chest wall lesions, but the splenic lesion remained unchanged. Given the lack of response to treatment in the splenic metastasis and the significant decrease in lung metastases, the multidisciplinary team decided that a partial splenectomy combined with continued immunotherapy treatment would be appropriate as the success of immunotherapy was imminent within the splenic preservation.

OUTCOMES

The postoperative recovery was smooth and the patient was discharged from hospital on the sixth postoperative day with normal platelets and white blood cells. The histopathological analysis of the resected specimen showed a metastatic melanoma with negative margins.At 10-month follow-up after the splenic resection the patient had not experienced further tumour recurrences.

LESSONS

Spleen-preserving resection for an isolated, solitary splenic metastasis of melanoma is a feasible approach as it not only preserves the ongoing efficacy of checkpoint inhibitors by preserving the physiological T cell milieu, but the immunomodulation properties of RF can produce potentially additional therapeutic benefit.

The importance for immunoregulation for long-term cancer control

Immune checkpoint blockades have recently emerged as a breakthrough treatment for solid tumors showing high response rates and long durability. In melanoma, the combination of ipilimumab with nivolumab showed high efficacy. However, still half the patients do not respond to this treatment. In order to increase the therapeutic ratio in melanoma and other cancers, different approaches are under evaluation. Three relevant questions are at the moment driving the research community: how to maximize benefit while minimizing toxicity; how to better identify patients who are more likely to benefit from immunotherapy; how to convert nonresponders into responders. In this review we summarize the most recent findings and we outline the most likely future challenges.

Correlation of Antibody Responses to a Peptide Antigen gp120-C5501-512/gp41732-744 with HIV Disease Progression

Antibodies to the carboxy-terminal constant (C5) region 5 of the HIV-1 envelope glycoprotein gp120 have previously been associated with slow disease progression. This is one of the regions on gp120 that interact with the transmembrane glycoprotein, gp41, anchoring it to the viral and infected cell membrane. This study analyzed humoral responses to a novel heterodimeric peptide construct comprising the C5^501-512 region and a compatible region on gp41^732-744. Antibody levels to C5^501-512/gp41^732-744 were associated with slow disease progression in a treatment naive historical longitudinal cohort from Norway (n = 32; p = .00001). Elevated anti-C5^501-512/gp41^732-744 antibody levels correlated with moderate viral load (VL) (50-10,000 copies/ml) in a cohort, including natural viral suppressors (NVS) in the Unites States (n = 58; p = .002). Analysis of HIV-positive sera from treatment naive patients in Estonia (n = 300) showed an inverse correlation between anti-C5^501-512/gp41^732-744 antibodies and VL when comparing VL 2,000-10,000 copies/ml with VL >10,000 (p = .050). Further mapping using peptide inhibition of antibody binding revealed that responses to the C5^501-506 subdomain correlated with preserved CD4 counts (n = 55; p = .0012) irrespective of VL in this cohort. The C5 region encompassing C5^501-506 shows sequence similarity to the shared epitope (SE) of certain HLA-DR associated with immune dysfunction. Partial antigenic cross-reactivity between SE and C5 is indicated by partial inhibition of NVS antibody binding using SE 15-mer peptide (median 65% inhibition), the C5^501-506 6-mer peptide (79% inhibition), and binding of rheumatoid arthritis patient sera to both SE and C5 peptide sequences. The potential influence of these observations on HIV-1 pathogenesis remains to be determined.

Interview with Professor Angus Dalgleish

Angus Dalgleish is the Foundation Professor of Oncology at St. George's University of London and Principal of the Institute for Cancer Vaccines and Immunotherapy.

Ipilimumab in the real world: the UK expanded access programme experience in previously treated advanced melanoma patients

Before licensing, ipilimumab was first made available to previously treated advanced melanoma patients through an expanded access programme (EAP) across Europe. We interrogated data from UK EAP patients to inform future clinical practice. Clinicians registered in the UK EAP provided anonymized patient data using a prespecified variable fields datasheet. Data collected were baseline patient characteristics, treatment delivered, toxicity, response, progression-free survival and overall survival (OS). Data were received for 193 previously treated metastatic melanoma patients, whose primary sites were cutaneous (82%), uveal (8%), mucosal (2%), acral (3%) or unknown (5%). At baseline, 88% of patients had a performance status (PS) of 0-1 and 20% had brain metastases. Of the patients, 53% received all four planned cycles of ipilimumab; the most common reason for stopping early was disease progression, including death from melanoma. Toxicity was recorded for 171 patients, 30% of whom experienced an adverse event of grade 3 or higher, the most common being diarrhoea (13%) and fatigue (9%). At a median follow-up of 23 months, the median progression-free survival and OS were 2.8 and 6.1 months, respectively; the 1-year and 2-year OS rates were 31 and 14.8%, respectively. The 2-year OS was significantly lower for patients with poorer PS (P<0.0001), low albumin concentrations (P<0.0001), the presence of brain metastases (P=0.007) and lactate dehydrogenase levels more than two times the upper limit of normal (P<0.0001) at baseline. These baseline characteristics are negative predictors of benefit from ipilimumab and should be taken into consideration before prescription.

Developments in HIV-1 immunotherapy and therapeutic vaccination

Since the human immunodeficiency virus (HIV-1) pandemic began, few prophylactic vaccines have reached phase III trials. Only one has shown partial efficacy in preventing HIV-1 infection. The introduction of antiretroviral therapy (ART) has had considerable success in controlling infection and reducing transmission but in so doing has changed the nature of HIV-1 infection for those with access to ART. Access, compliance, and toxicity alongside the emergence of serious non-AIDS morbidity and the sometimes poor immune reconstitution in ART-treated patients have emphasized the need for additional therapies. Such therapy is intended to contribute to control of HIV-1 infection, permit structured treatment interruptions, or even establish a functional cure of permanently suppressed and controlled infection. Both immunotherapy and therapeutic vaccination have the potential to reach these goals. In this review, the latest developments in immunotherapy and therapeutic vaccination are discussed.

Revisiting the role of systemic therapies in patients with metastatic melanoma to the CNS

The CNS is a common site of metastasis in patients with malignant melanoma. Locoregional control either with surgery or radiotherapy is first-line treatment for patients with brain metastasis should they be suitable candidates. For those patients who are not and those who progress after previous treatment, there is an unmet clinical need for effective systemic therapies. Systemic cytotoxics, such as temozolamide and fotemustine, have only modest activity, resulting in a median progression-free survival ranging from 1-2 months, in patients with metastatic melanoma to the brain. Newer systemic treatments such as vemurafenib and ipilimumab have been approved for the treatment of melanoma, but evidence regarding their activity in brain metastases is inconclusive due to the limited access of patients to clinical trials. This is now being revised and more data are emerging supporting the inclusion of patients with brain metastasis in trials. In this review, the authors present data regarding the efficacy of systemically administered therapies in patients with metastatic melanoma to the brain.

Mechanisms of action of tasquinimod on the tumour microenvironment

Tasquinimod is a small molecule with pleiotropic effects on the tumour microenvironment. Tasquinimod inhibits the growth and metastasis of tumour cells in vitro and in vivo. It targets the tumour microenvironment, enhancing the host immune response and inhibiting the angiogenic response. Tasquinimod influences infiltrating myeloid cells in the tumour milieu shifting the balance towards a less immunosuppressive phenotype. Myeloid-derived suppressor cells and tumour-associated macrophages are major components of the immunosuppressive microenvironment and as a result promote tumour growth and favour angiogenesis and metastasis formation. Growing evidence indicates that tasquinimod targets these myeloid cells and modulates local tumour immunity by blocking the interaction between the multifunctional protein S100A9 and its ligands receptor of advanced glycation end products and Toll-like receptor 4. Its anti-angiogenic effects are achieved at least in part through these effects on regulatory myeloid cells and also potentially through inactivating histone deacetylase-4 and reducing expression of hypoxia-inducible factor 1-controlled genes. The aim is to comprehensively review the mode of action of tasquinimod as a novel oral anti-cancer agent. Based on its unique combination of effects, tasquinimod is a novel agent with clinical therapeutic potential in various solid tumours, both alone and as part of rational combination therapy.

Ipilimumab in the real world: The U.K. expanded access programme (EAP) experience in advanced melanoma

3018

Background: Since publication of the registration trial in 2010 (Hodi et al, NEJM 2010;363:711-23), real world use of ipilimumab (Ipi) in previously treated advanced melanoma patients has extended beyond the specific trial entry criteria of ECOG PS 0-1. We undertook a review of UK patients (pts) treated in the international EAP prior to European licensing of Ipi in August 2011, to compare real world survival outcomes. Methods: UK clinicians registered in the EAP provided anonymised data using pre-specified variable fields for all pts. The EAP stipulated pts should have previously treated, unresectable stage III or IV metastatic melanoma and receive Ipi 3 mg/kg, 3 weekly IV, for up to 4 cycles. Response using RECIST criteria was assessed 12 weekly. Grade ≥3 adverse events (AEs) using CTCAE v3.0 were collected. Results: To date, information on 162 pts has been received from 16 UK sites. Primary sites were: 78% cutaneous, 4% ocular, 1% mucosal, 17% unknown. 78% pts had M1c disease, 14% had brain metastases. No prior therapies ranged from 0-4, 72% pts received 1 prior therapy. Median age was 60 years, men>women (1.6:1). ECOG PS was: 38% 0, 47% 1, 14% 2, 1% 3. BRAF status was known in 38% cases and WT in 75% of these. 19% pts were on steroids at baseline. No cycles delivered was 4 in 52%, 3 in 13%, 2 in 16%, 1 in 17% pts. Most frequent reason for stopping early was clinical evidence of disease progression (71%), death (16%) or unacceptable AE (12%). 32% pts experienced a grade ≥3 AE, the most common being diarrhoea (13%) and fatigue (8%). Complete and partial responses were reported in 1% and 21% of treated pts. At median follow-up of 17 months, median progression free survival and overall survival (OS) were 2.8 and 5.7 months, 1 year OS was 30%. Comparing outcomes of various pt subgroups, the strongest prognostic factor for OS was ECOG PS at the start of treatment (p<0.0001). For pts with PS 0 or 1, median OS was 8.8 months (compared with 10 months in the registration trial). More detailed safety and efficacy data on pt subgroups will be presented. Conclusions: This review, representing the largest Ipi EAP UK dataset, reports overall poorer survival outcomes than in the registration trial, but pts with similar characteristics to the trial population lived longer.

Treatment with a combination of the ErbB (HER) family blocker afatinib and the IGF-IR inhibitor, NVP-AEW541 induces synergistic growth inhibition of human pancreatic cancer cells

Background

Aberrant expression and activation of the IGF-IR have been reported in a variety of human cancers and have been associated with resistance to HER targeted therapy. In this study, we investigated the effect of simultaneous targeting of IGF-IR and HER (erbB) family, with NVP-AEW541 and afatinib, on proliferation of pancreatic cancer cells.

Methods

The sensitivity of a panel of human pancreatic cancer cell lines to treatment with NVP-AEW541 used alone or in combination with afatinib, anti-EGFR antibody ICR62, and cytotoxic agents was determined using the Sulforhodamine B colorimetric assay. Growth factor receptor expression, cell-cycle distribution and cell signalling were determined using flow cytometry and western blot analysis.

Results

All pancreatic cancer cell lines were found to be IGF-IR positive and NVP-AEW541 treatment inhibited the growth of the pancreatic cancer cell lines with IC50 values ranging from 342 nM (FA6) to 2.73 μM (PT45). Interestingly, of the various combinations examined, treatment with a combination of NVP-AEW541 and afatinib was superior in inducing synergistic growth inhibition of the majority of pancreatic cancer cells.

Conclusion

Our results indicate that co-targeting of the erbB (HER) family and IGF-IR, with a combination of afatinib and NVP-AEW541, is superior to treatment with a single agent and encourages further investigation in vivo on their therapeutic potential in IGF-IR and HER positive pancreatic cancers.

Analysis of K-ras gene mutations in human pancreatic cancer cell lines and in bile samples from patients with pancreatic and biliary cancers

The ras family of oncogenes are the most frequently activated group of dominant transforming genes in both human and experimental cancers. The ras family of genes encode highly similar proteins with molecular weights of 21 kDa which are thought to play a key role in signal transduction. Activation in vivo by point mutations results in the ras p21 protein being maintained in the activated form and stimulating cellular proliferation autonomously. Point mutations at codon 12 of K-ras have been observed in >75% of cases of adenocarcinomas of the exocrine pancreas. The type and frequency of K-ras gene mutations in pancreatic cancer cell lines and in bile samples from patients with cytologically-proven biliary tract malignancies and from patients with non-malignant disorders of the biliary tract were determined. Codons 12, 13 and 61 of the K-ras gene were analysed by using restriction fragment length polymorphisms created through mismatched primers during polymerase chain reaction (PCR) of genomic DNA. A mutation of codon 12 of K-ras was detected in 10 of 13 (77%) human pancreatic cancer cell lines. The amino-acid substitutions were glycine to aspartate (5 samples), arginine (2), valine (2) and cysteine (1). No mutations were found at codons 13 or 61. A mutation at codon 12 of K-ras was detected in 9 of 18 (50%) of bile samples analysed. Eleven bile samples had positive cytology for malignancy of pancreaticobiliary origin, and 4 (36%) of these had a codon 12 mutation. Mutations were detected in 5 of the 7 (71%) cytologically-negative bile samples, although malignancy was subsequently diagnosed in 2 of these patients on further histology, and was suspected in 3 other cases on clinical and radiological criteria. This method provides a rapid determination of K-ras gene mutations in bile samples for patients with pancreatic and biliary tract diseases, which may be useful when considering future therapy directed at inhibition of activated ras-induced signal transduction pathways.

Expression pattern and targeting of HER family members and IGF-IR in pancreatic cancer

Pancreatic cancer is still one of the most aggressive and fatal types of human cancer . Survival rates for patients with pancreatic cancer are extremely poor and one major contributing factor is the lack of specific marker(s) for the early detection of pancreatic cancer. Indeed, the great majority of pancreatic cancer cases are diagnosed at an advanced stage of the disease and these patients often have a poor response to treatment with conventional forms of therapy. In this article, we conduct a comprehensive review of the literature on the expression pattern, prognostic significance and predictive value of EGFR family members, IGF-IR and their ligands in pancreatic cancer. We also discuss recent advances in pancreatic cancer treatments and highlight the remaining challenges as well as future opportunities for more effective targeting of such receptors using a combination of growth factor receptor specific monoclonal antibodies, small molecule tyrosine kinase inhibitors and other therapeutic strategies. Such strategies could ultimately help to overcome the development of drug resistance and improve the overall survival rates for patients with pancreatic cancer.

An intra-patient placebo-controlled phase I trial to evaluate the safety and tolerability of intradermal IMM-101 in melanoma

BACKGROUND

IMM-101 is a heat-killed innate and adaptive immune-activating mycobacterial product; a phase I study aimed to determine its safety and tolerability in individuals with melanoma.

PATIENTS AND METHODS

An intra-patient placebo-controlled study evaluated the safety and tolerability of three doses, namely, 0.1 (1 mg/ml), 0.5 (5 mg/ml) and 1.0 mg (10 mg/ml) of IMM-101 in stage III or IV melanoma. Each dose was administered in ascending order to one of the three cohorts.

RESULTS

Based on observations from patients administered the 0.1-mg dose, it was considered appropriate to proceed with dosing the patients in the 0.5-mg dose cohort and then the 1.0-mg cohort (n = 6 per cohort). Treatment-emergent adverse events that would be considered typical of a post-vaccination state (including joint pains/aches, headaches and influenza-like symptoms) occurred at all dose levels, along with injection site reactions. These were mainly mild in intensity, resolved in a matter of days and responded well to supportive care. During post-study follow-up, two clinical responses (15%) were observed in patients with stage IV disease.

CONCLUSION

IMM-101 is safe and well tolerated and there is a rationale for studying IMM-101 at a nominal 1.0-mg dose to complement conventional cytotoxic therapy for patients with advanced cancer.

Poly(I:C)-induced tumour cell death leads to DC maturation and Th1 activation

Dendritic cells (DCs) have the ability to generate peptide epitopes for MHC class I molecules derived from apoptotic tumour cells for direct recognition by cytotoxic T cells. This function has lead to DCs being used in vaccine strategies. In this study, we investigate the effect of inducing apoptosis in tumour cell lines using IFN-γ and poly(I:C), the subsequent maturation of the endocytosing DC and its ability to direct the resulting T cell response. We show that uptake of poly(I:C)-induced apoptotic tumour cells leads to DC maturation and activation with a Th1 cell polarising capacity. In contrast, these effects are not seen by DCs loaded with γ-irradiated apoptotic tumour cells. We propose that the manner in which tumour cells are induced to die can have a profound effect on the endocytosing DC and the resulting T cell response.

Increased PRAME antigen-specific killing of malignant cell lines by low avidity CTL clones, following treatment with 5-Aza-2'-Deoxycytidine

The cancer testis antigen Preferentially Expressed Antigen of Melanoma (PRAME) is overexpressed in many solid tumours and haematological malignancies whilst showing minimal expression in normal tissues and is therefore a promising target for immunotherapy. HLA-A0201-restricted peptide epitopes from PRAME have previously been identified as potential immunogens to drive antigen-specific autologous CTL responses, capable of lysing PRAME expressing tumour cells. CTL lines, from 13 normal donors and 10 melanoma patients, all of whom were HLA-A0201 positive, were generated against the PRAME peptide epitope PRA(100-108). Specific killing activity against PRA(100-108) peptide-pulsed targets was weak compared with CTL lines directed against known immunodominant peptides. Moreover, limiting dilution cloning from selected PRAME-specific CTL lines resulted in the generation of a clone of only low to intermediate avidity. Addition of the demethylating agent 5-aza-2'-Deoxycytidine (DAC) increased PRAME expression in 7 out of 11 malignant cell lines including several B lineage leukaemia lines and also increased class I expression. Pre-treatment of target cells was associated with increased sensitivity to antigen-specific killing by the low avidity CTL. When CTL, as well as of the target cells, were treated, the antigen-specific killing was further augmented. Interestingly, one HLA-A0201-negative DAC-treated line (RAJI) showed increased sensitivity to killing by clones despite a failure of expression of PRAME or HLA-A0201. Together these data point to a general increased augmentation of cancer immunogenocity by DAC involving both antigen-specific and non-specific mechanisms.

Abstract 630: Responses of human pancreatic cancer cells to treatment with insulin-like growth factor receptor (IGF-IR) tyrosine kinase inhibitor NVP-AEW541 alone and in combination with anti-EGFR mAb ICR62 or cytotoxic drugs

Aberrant expression and activation of growth factor receptor signalling pathways including epidermal growth factor receptor (EGFR) and the insulin-like growth factor receptor (IGF-IR) have been reported in a wide range of epithelial cancers and have been associated with increased cell proliferation, reduced apoptosis, invasion and metastasis. Of the growth factor receptor inhibitors, the EGFR inhibitor erlotinib has been approved for the treatment of pancreatic cancer. However, its overall therapeutic efficacy can be of short duration. In some studies, signalling with the IGF-IR has been associated with resistance to therapy with the EGFR inhibitors. In this study, using the Sulforhodamine B colorimetric assay, we investigated the sensitivity of a panel of human pancreatic cancer cell lines (PT-45, AsPC1, PANC1, MiaPaca2, BxPC3, Capan1 and FA6) to treatment with IGF-IR tyrosine kinase inhibitor NVP-AEW541 alone or in combination with anti-EGFR monoclonal antibody (mAb) ICR62 and cytotoxic agents (i.e. 5-FU, doxycycline and gemcitabine). We also investigated the association between the expression levels of IGF-IR and EGFR in these tumour cells, determined by flow cytometry, and their responses to treatment with NVP-AEW541 and/or ICR62. At concentrations above 5μM, NVP-AEW541 inhibited completely the growth of most of the pancreatic cancer cell lines with IC50 values ranging from 342nM (FA6) to 2.73μM (PT45). At maximum concentration of 150nM used in this study, ICR62 did not have any effect on the growth of human pancreatic tumour cell lines. In addition, treatment with a combination of ICR62 and NVP-AEW541 did not enhance the inhibitory effect of the single agent in pancreatic cancer cells. Interestingly, treatment with a combination of NVP-AEW541 and gemcitabine was found to be synergistic for AsPC1 and PANC1 cells, additive for BxPC3, MiaPaca2 and PT-45 cells, but antagonistic for FA6 and CAPAN1 cells. We also examined the cell cycle distribution of BxPC3 cells following treatment with NVP-AEW541 and found an increase in the population of cells in sub-G1 and G0/G1 phases. In contrast, gemcitabine treatment of BxPC3 cells was accompanied by an increase in the populations of cells in both the sub-G1 and S phases of the cell cycle. Taken together, our results suggest that dual targeting of the EGFR and IGF-IR in pancreatic cancer cells by a combination of ICR62 and NVP-AEW541 is not superior to treatment with the single agent in vitro. Further investigations in vivo on the anti-tumour activity of the NVP-AEW541 in combination with ICR62 and cytotoxic drugs in pancreatic cancer are warranted.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 630. doi:10.1158/1538-7445.AM2011-630

Current status and future applications of cellular therapies for cancer

Therapies based on the use of autologous immune cells are among the best candidates for cancer immunotherapy. Dendritic cell vaccines have demonstrated very encouraging responses for some solid tumors, while in melanoma autologous T-cell therapies have exceeded 70% objective response rates in selected Phase I trials. However, it is clear that a number of barriers exist to the effective, practical application of these therapies. The aim of this article is to consider modifications to such strategies over the last 3 years and the resultant clinical research in autologous dendritic cell vaccines, T-cell therapy and γδ T-cell therapy for cancer.

The potential of immunomodulatory drugs in the treatment of solid tumors

Lenalidomide (REVLIMID®) CC-5013 (Celgene, NJ, USA) is approved, in both the USA and Europe, in combination with dexamethasone for the treatment of multiple myeloma patients who have received at least one prior therapy, and is rapidly being accepted worldwide for this condition. Lenalidomide is also approved in the USA and Canada for use in transfusion-dependent anemia in patients with low- and intermediate-1-risk myelodysplastic syndromes associated with del (5q) abnormality with or without additional abnormalities. Lenalidomide is an IMiD® immunomodulatory compound, incorporating structural modification of the drug thalidomide, which is active against a wide variety of autoimmune Th-2-dependent disorders, including erythema nodosum of leprosy, leishmaniasis, as well as severe ulcerative disorders such as Behcet's syndrome. Unfortunately, long-term use of thalidomide is limited, particularly by neurotoxicity. To date, results suggest that lenalidomide is more active than thalidomide and does not cause the neurotoxicity seen with thalidomide. Lenalidomide has multiple properties, including anti-inflammatory, antiangiogenic and costimulatory effects, as well as being able to inhibit T-regulatory cells, all of which are properties deemed desirable for anticancer activity. This article covers the evidence that lenalidomide may have a major role in the treatment and control of many cancer types other than del (5q) myelodysplastic syndrome and multiple myeloma.

Recent Pharmacological Advances: Focus on Small-cell Lung Cancer

Small cell lung cancer (SCLC) represents approximately 15% of all lung cancers, and is the most aggressive form of lung cancer. Left untreated, the time from diagnosis to death is 2–3 months. With current treatment, expected survival is 7–20 months, depending on the stage of disease. A new drug, amrubicin, is approved in Japan for lung cancer and has demonstrated efficacy in U.S. and European phase II trials of SCLC patients with either untreated disease or relapsed refractory illness. In a phase II study of amrubicin in previously untreated patients, response rates reached 75% with a median survival time of almost 1 year. Amrubicin is a fully synthetic 9-aminoanthracycline, and an analog of doxorubicin and epirubicin. The major mechanism of action of amrubicin is inhibition of topoisomerase II. Unlike doxorubicin, however, it exhibits little or no cardiotoxicity in clinical studies and preclinical models. In preclinical rodent tumor models, it is selectively distributed to tumour tissue and is not detected in the heart when compared with doxorubicin, which is distributed equivalently to these sites. The primary metabolite of amrubicin, amrubicinol, is up to 100 times more cytotoxic in vitro than the parent compound. This review describes the mechanisms of action of amrubicin as well as clinical studies which demonstrate the potential of this drug in future SCLC treatment. The review also puts forward hypothetical considerations for the use of other drugs such as lenalidomide, an immunomodulatory drug acting on multiple signalling pathways, or histone deacetylase inhibitors, in combination with amrubicin in SCLC.

T regulatory cells, the evolution of targeted immunotherapy

T regulatory cells are able to suppress anti-tumour immunity in pre-clinical models and in patients. This review highlights the important discoveries in Treg immunology critical to the evolution of targeted immunotherapy. We also describe the therapeutic applications that are currently being assessed and their future potential.

Whole-cell vaccines: A failure or a success waiting to happen?

Whole-cell vaccination has demonstrated efficacy in small phase I and II clinical trials. However, in the past 3 years several high-profile phase III trials have failed to meet the predicted endpoints, including trials of the GVAX technologies (BioSante Pharmaceuticals Inc [formerly Cell Genesys Inc]) conducted by Cell Genesys. This review discusses the potential reasons for the failure of selected phase III trials and summarizes the current status of whole-cell vaccination, with specific reference to trials conducted in the past 2 years. Recently, new paradigms have emerged in the field of cancer vaccine research. In particular, the potential use of combination therapies that incorporate immune modulators and standard radio- and chemotherapy to synergize with whole-cell vaccines is discussed. In addition, key measures for improvements within the field that may be required for the generation of effective antitumor immunity are identified.

Overview of Tumor Cell–Based Vaccines

Whole-cell tumor vaccines have been investigated for more than 20 years for their efficacy in both preclinical models and in clinical trials in humans. There are clear advantages of whole-cell/polyepitope vaccination over those types of immunotherapy that target specific epitopes. Multiple and unknown antigens may be targeted to both the innate and adaptive immune system, and this may be further augmented by genetic modification of the vaccine cells to provide cytokines and costimulation. In this review, we give an overview of the field including the preclinical and clinical advances using unmodified and modified tumor-cell vaccines.

T-regulatory cell modulation: the future of cancer immunotherapy?

T-regulatory cells suppress anti-tumour immunity in cancer patients and in murine tumour models. Furthermore, their activity is likely to have an effect on the effectiveness of immunotherapeutic treatments for cancer. Here we describe the current status of developing clinical strategies for modulating Treg activity in cancer patients.

A prostate cancer vaccine comprising whole cells secreting IL-7, effective against subcutaneous challenge, requires local GM-CSF for intra-prostatic efficacy

A panel of cytokine-secreting RM-9 prostate cancer cells were tested as whole cell vaccines to determine their capacity to evoke an anti-prostate cancer immune response. In our model, vaccines secreting mGM-CSF or mIL-7 resulted in the highest increase in circulating T lymphocytes after vaccination, prolonged survival and, in a proportion of animals, tumor-free survival. Anti-tumor effects were more evident after a subcutaneous RM-9 challenge than after an intraprostatic challenge. However, when the RM-9/mGM-CSF cell line was used as intraprostatic tumor challenge, protection after RM-9/mIL-7 vaccination was restored.