Sarah Rudman

Characterisation of an engineered trastuzumab IgE antibody and effector cell mechanisms targeting HER2/neu-positive tumour cells

Trastuzumab (Herceptin®), a humanized IgG1 antibody raised against the human epidermal growth factor receptor 2 (HER2/neu), is the main antibody in clinical use against breast cancer. Pre-clinical evidence and clinical studies indicate that trastuzumab employs several anti-tumour mechanisms that most likely contribute to enhanced survival of patients with HER2/neu-positive breast carcinomas. New strategies are aimed at improving antibody-based therapeutics like trastuzumab, e.g. by enhancing antibody-mediated effector function mechanisms. Based on our previous findings that a chimaeric ovarian tumour antigen-specific IgE antibody showed greater efficacy in tumour cell killing, compared to the corresponding IgG1 antibody, we have produced an IgE homologue of trastuzumab. Trastuzumab IgE was engineered with the same light- and heavy-chain variable-regions as trastuzumab, but with an epsilon in place of the gamma-1 heavy-chain constant region. We describe the physical characterisation and ligand binding properties of the trastuzumab IgE and elucidate its potential anti-tumour activities in functional assays. Both trastuzumab and trastuzumab IgE can activate monocytic cells to kill tumour cells, but they operate by different mechanisms: trastuzumab functions in antibody-dependent cell-mediated phagocytosis (ADCP), whereas trastuzumab IgE functions in antibody-dependent cell-mediated cytotoxicity (ADCC). Trastuzumab IgE, incubated with mast cells and HER2/neu-expressing tumour cells, triggers mast cell degranulation, recruiting against cancer cells a potent immune response, characteristic of allergic reactions. Finally, in viability assays both antibodies mediate comparable levels of tumour cell growth arrest. These functional characteristics of trastuzumab IgE, some distinct from those of trastuzumab, indicate its potential to complement or improve upon the existing clinical benefits of trastuzumab.

Global incidence and outcome of testicular cancer

Background Testicular cancer is a rare tumor type accounting for 1% of malignancies in men. It is, however, the most common cancer in young men in Western populations. The incidence of testicular cancer is increasing globally, although a decline in mortality rates has been reported in Western countries. It is important to identify whether the variations in trends observed between populations are linked to genetic or environmental factors. Methods Age-standardized incidence rates and age-standardized mortality rates for testicular cancer were obtained for men of all ages in ten countries from the Americas, Asia, Europe, and Oceania using the Cancer Incidence in Five Continents (CI5plus) and World Health Organization (WHO) mortality databases. The annual percent change was calculated using Joinpoint regression to assess temporal changes between geographical regions. Results Testicular cancer age-standardized incidence rates are highest in New Zealand (7.8), UK (6.3), Australia (6.1), Sweden (5.6), USA (5.2), Poland (4.9), and Spain (3.8) per 100,000 men. India, China, and Colombia had the lowest incidence (0.5, 1.3, and 2.2, respectively) per 100,000 men. The annual percent changes for overall testicular cancer incidence significantly increased in the European countries Sweden 2.4%, (2.2; 2.6); UK 2.9%, (2.2; 3.6); and Spain 5.0%, (1.7; 8.4), Australia 3.0%, (2.2; 3.7), and China 3.5%, (1.9; 5.1). India had the lowest overall testicular cancer incidence −1.7%, (−2.5; −0.8). Annual percent changes for overall testicular cancer mortality rates were decreasing in all study populations, with the greatest decline observed in Sweden −4.2%, (−4.8; −3.6) and China −4.9%, (−6.5; −3.3). Conclusion Testicular cancer is increasing in incidence in many countries; however, mortality rates remain low and most men are cured. An understanding of the risks and long-term side effects of treatment are important in managing men with this disease.

EGFR inhibitors in non-small cell lung cancer (NSCLC): the emerging role of the dual irreversible EGFR/HER2 inhibitor BIBW 2992

Non-small cell lung cancer (NSCLC) is one of the most lethal types of cancer and is associated with significant mortality and morbidity worldwide. Despite improvements in conventional treatment for NSCLC, survival remains poor and improvements in patient outcome are warranted. Over recent years, basic scientific research has dramatically increased our knowledge of the pathogenesis of lung cancer and allowed us to uncover and understand the cellular pathways involved in this process. This has led to the development of therapies to selectively target these pathways. Among these, the epidermal growth factor receptor (EGFR) tyrosine kinase family and related downstream pathways play a critical role in cancer development and over recent years have become a validated target in NSCLC. The development of monoclonal antibodies and first-generation tyrosine kinase inhibitors (TKIs) targeted towards EGFR has had a considerable impact on patient outcomes. However, despite dramatic and sustained responses and the discovery of specific patient subgroups that may derive clinical benefit, resistance to first-generation EGFR TKIs inevitably develops. A new generation of agents have been developed to provide superior potency of target inhibition and further individualize the treatment of NSCLC. This article reviews EGFR-targeted therapies currently available for use and undergoing clinical development for the treatment of NSCLC, specifically focusing on next generation agents including BIBW 2992, an irreversible dual inhibitor of EGFR and HER2 kinases.

A Phase 1 Study of AS1409, a Novel Antibody-Cytokine Fusion Protein, in Patients with Malignant Melanoma or Renal Cell Carcinoma

Purpose: AS1409 is a fusion protein comprising a humanized antibody BC1 linked to interleukin-12 (IL-12). It is designed to deliver IL-12 to tumor-associated vasculature using an antibody targeting the ED-B variant of fibronectin. Experimental Design: We conducted a phase 1 trial of weekly infusional AS1409 in renal carcinoma and malignant melanoma patients. Safety, efficacy, markers of IL-12–mediated immune response, and pharmacokinetics were evaluated. Results: A total of 11 melanoma and 2 renal cell carcinoma patients were treated. Doses of 15 and 25 μg/kg were studied. Most drug-related adverse events were grade 2 or less, and included pyrexia, fatigue, chills, headache, vomiting, and transient liver function abnormalities. Three dose limiting toxicities of grade 3 fatigue and transaminase elevation were seen at 25 μg/kg. IFN-γ and interferon-inducible protein-10 (IP-10) were elevated in all patients, indicating activation of cell-mediated immune response; this was attenuated at subsequent cycles. Antidrug antibody responses were seen in all patients, although bioassays indicate these do not neutralize AS1409 activity. Plasma half-life was 22 hours and not dose-dependent. Five patients received 6 cycles or more and a best response of at least stable disease was seen in 6 (46%) patients. Partial response was seen in a melanoma patient, and disease shrinkage associated with metabolic response was maintained beyond 12 months in another melanoma patient despite previous rapid progression. Conclusions: The maximum tolerated dose was established at 15 μg/kg weekly. AS1409 is well tolerated at this dose. Evidence of efficacy assessed by RECIST, functional imaging, and biomarker response warrants the planned further investigation using this dose and schedule in malignant melanoma. Clin Cancer Res; 17(7); 1998–2005. ©2011 AACR.

Quantifying the Evidence for the Risk of Metabolic Syndrome and Its Components following Androgen Deprivation Therapy for Prostate Cancer: A Meta-Analysis

Background No meta-analysis is yet available for the risk of metabolic syndrome (MetS) following androgen deprivation therapy (ADT) for men with prostate cancer. To summarize the evidence for the link between ADT and MetS or its components quantitatively with a meta-analysis including all studies published to date. Methods PubMed and Embase were searched using predefined inclusion criteria to perform meta-analyses on the association between metabolic syndrome, hyperglycemia, diabetes, hypertension, dyslipidemia or obesity and androgen deprivation therapy in patients with prostate cancer. Random effects methods were used to estimate pooled relative risks (RRs) and 95% confidence intervals (CI). Results A total of nine studies was included. There was a positive association between ADT and risk of MetS (RR: 1.75 (95% CI: 1.27–2.41)). Diabetes was the only MetS component present in more than 3 studies, and also showed an increased risk following ADT (RR: 1.36 (95% CI: 1.17–1.58)). Conclusion This is the first quantitative summary addressing the potential risk of MetS following ADT in men with PCa. The positive RRs indicate that there is a need to further elucidate how type and duration of ADT affect these increased risks of MetS and diabetes as the number of men with PCa treated with ADT is increasing.

Recombinant IgE antibodies for passive immunotherapy of solid tumours: from concept towards clinical application

Therapeutic antibodies have revolutionised treatment of some cancers and improved prognosis for many patients. Over half of those available are approved for haematological malignancies, but efficacious antibodies for solid tumours are still urgently needed. Clinically available antibodies belong to the IgG class, the most prevalent antibody class in human blood, while other classes have not been extensively considered. We hypothesised that the unique properties of IgE, a class of tissue-resident antibodies commonly associated with allergies, which can trigger powerful immune responses through strong affinity for their particular receptors on effector cells, could be employed for passive immunotherapy of solid tumours such as ovarian and breast carcinomas. Our laboratory has examined this concept by evaluating two chimaeric antibodies of the same specificity (MOv18) but different isotype, an IgG1 and an IgE against the tumour antigen folate receptor α (FRα). The latter demonstrates the potency of IgE to mount superior immune responses against tumours in disease-relevant models. We identified Fcε receptor-expressing cells, monocytes/macrophages and eosinophils, activated by MOv18 IgE to kill tumour cells by mechanisms such as ADCC and ADCP. We also applied this notion to a marketed therapeutic, the humanised IgG1 antibody trastuzumab and engineered an IgE counterpart, which retained the functions of trastuzumab in restricting proliferation of HER2/neu-expressing tumour cells but also activated effector cells to kill tumour cells by different mechanisms. On-going efficacy, safety evaluations and future first-in-man clinical studies of IgE therapeutics constitute key metrics for this concept, providing new scope for antibody immunotherapies for solid tumours.

Harnessing engineered antibodies of the IgE class to combat malignancy: initial assessment of FcɛRI‐mediated basophil activation by a tumour‐specific IgE antibody to evaluate the risk of type I hypersensitivity

Background IgE antibodies, sequestered into tissues and retained locally by the high‐affinity IgE receptor, FcɛRI, on powerful effector cells such as mast cells, macrophages and eosinophils, may offer improvements in the therapy of solid tumours. The chimeric antibody, MOv18 IgE, against the human ovarian carcinoma antigen, folate receptor α (FRα), is more effective than its IgG1 counterpart in xenograft models of ovarian cancer. Although MOv18 IgE binds to a single epitope on FRα and cannot cross‐link IgE receptors on basophils, there remains a risk that components in the circulation of ovarian cancer patients might cross‐link FRα‐MOv18‐IgE‐receptor‐FcɛRI complexes on basophils to cause type I hypersensitivity.

Monitoring the Systemic Human Memory B Cell Compartment of Melanoma Patients for Anti-Tumor IgG Antibodies

Melanoma, a potentially lethal skin cancer, is widely thought to be immunogenic in nature. While there has been much focus on T cell-mediated immune responses, limited knowledge exists on the role of mature B cells. We describe an approach, including a cell-based ELISA, to evaluate mature IgG antibody responses to melanoma from human peripheral blood B cells. We observed a significant increase in antibody responses from melanoma patients (n = 10) to primary and metastatic melanoma cells compared to healthy volunteers (n = 10) (P<0.0001). Interestingly, we detected a significant reduction in antibody responses to melanoma with advancing disease stage in our patient cohort (n = 21) (P<0.0001). Overall, 28% of melanoma patient-derived B cell cultures (n = 1,800) compared to 2% of cultures from healthy controls (n = 600) produced antibodies that recognized melanoma cells. Lastly, a patient-derived melanoma-specific monoclonal antibody was selected for further study. This antibody effectively killed melanoma cells in vitro via antibody-mediated cellular cytotoxicity. These data demonstrate the presence of a mature systemic B cell response in melanoma patients, which is reduced with disease progression, adding to previous reports of tumor-reactive antibodies in patient sera, and suggesting the merit of future work to elucidate the clinical relevance of activating humoral immune responses to cancer.

Tracking Cancer Evolution Reveals Constrained Routes to Metastases: TRACERx Renal

Summary Clear-cell renal cell carcinoma (ccRCC) exhibits a broad range of metastatic phenotypes that have not been systematically studied to date. Here, we analyzed 575 primary and 335 metastatic biopsies across 100 patients with metastatic ccRCC, including two cases sampledat post-mortem. Metastatic competence was afforded by chromosome complexity, and we identify 9p loss as a highly selected event driving metastasis and ccRCC-related mortality (p = 0.0014). Distinct patterns of metastatic dissemination were observed, including rapid progression to multiple tissue sites seeded by primary tumors of monoclonal structure. By contrast, we observed attenuated progression in cases characterized by high primary tumor heterogeneity, with metastatic competence acquired gradually and initial progression to solitary metastasis. Finally, we observed early divergence of primitive ancestral clones and protracted latency of up to two decades as a feature of pancreatic metastases.

Is there an antiandrogen withdrawal syndrome with enzalutamide

To examine prostate‐specific antigen (PSA) levels after enzalutamide discontinuation to assess whether an antiandrogen withdrawal syndrome (AAWS) exists with enzalutamide.