Christy Ralph

DNA-Repair Defects and Olaparib in Metastatic Prostate Cancer

BACKGROUND Prostate cancer is a heterogeneous disease, but current treatments are not based on molecular stratification. We hypothesized that metastatic, castration-resistant prostate cancers with DNA-repair defects would respond to poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibition with olaparib. METHODS We conducted a phase 2 trial in which patients with metastatic, castration-resistant prostate cancer were treated with olaparib tablets at a dose of 400 mg twice a day. The primary end point was the response rate, defined either as an objective response according to Response Evaluation Criteria in Solid Tumors, version 1.1, or as a reduction of at least 50% in the prostate-specific antigen level or a confirmed reduction in the circulating tumor-cell count from 5 or more cells per 7.5 ml of blood to less than 5 cells per 7.5 ml. Targeted next-generation sequencing, exome and transcriptome analysis, and digital polymerase-chain-reaction testing were performed on samples from mandated tumor biopsies. RESULTS Overall, 50 patients were enrolled; all had received prior treatment with docetaxel, 49 (98%) had received abiraterone or enzalutamide, and 29 (58%) had received cabazitaxel. Sixteen of 49 patients who could be evaluated had a response (33%; 95% confidence interval, 20 to 48), with 12 patients receiving the study treatment for more than 6 months. Next-generation sequencing identified homozygous deletions, deleterious mutations, or both in DNA-repair genes--including BRCA1/2, ATM, Fanconis anemia genes, and CHEK2--in 16 of 49 patients who could be evaluated (33%). Of these 16 patients, 14 (88%) had a response to olaparib, including all 7 patients with BRCA2 loss (4 with biallelic somatic loss, and 3 with germline mutations) and 4 of 5 with ATM aberrations. The specificity of the biomarker suite was 94%. Anemia (in 10 of the 50 patients [20%]) and fatigue (in 6 [12%]) were the most common grade 3 or 4 adverse events, findings that are consistent with previous studies of olaparib. CONCLUSIONS Treatment with the PARP inhibitor olaparib in patients whose prostate cancers were no longer responding to standard treatments and who had defects in DNA-repair genes led to a high response rate. (Funded by Cancer Research UK and others; ClinicalTrials.gov number, NCT01682772; Cancer Research UK number, CRUK/11/029.).

Modulation of lymphocyte regulation for cancer therapy: a phase II trial of tremelimumab in advanced gastric and esophageal adenocarcinoma.

Purpose: Cytotoxic T lymphocyte antigen 4 (CTLA4), a key negative regulator of T-cell activation, is targeted by the antibody tremelimumab to release potentially useful antitumor activity. Experimental Design: This phase II trial investigated tremelimumab as a second-line treatment for patients with metastatic gastric and esophageal adenocarcinomas. Tremelimumab was given every 3 months until symptomatic disease progression. Safety, clinical efficacy, and immunologic activity were evaluated. Results: Eighteen patients received tremelimumab. Most drug-related toxicity was mild; however, there was a single death due to bowel perforation that complicated colitis. Four patients had stable disease with clinical benefit; one patient achieved a partial response after eight cycles (25.4 months) and remains well on study at 32.7 months. Markers of regulatory phenotype, forkhead box protein 3 and CTLA4, doubled transiently in CD4+CD25high lymphocytes in the first month after tremelimumab before returning to baseline. In contrast, CTLA4 increased in CD4+CD25low/negative lymphocytes throughout the cycle of treatment. De novo proliferative responses to tumor-associated antigens 5T4 (8 of 18 patients) and carcinoembryonic antigen (5 of 13) were detected. Patients with a posttreatment carcinoembryonic antigen proliferative response had median survival of 17.1 months compared with 4.7 months for nonresponders (P = 0.004). Baseline interleukin-2 release after T-cell activation was higher in patients with clinical benefit and toxicity. Conclusion: Despite the disappointing response rate of tremelimumab, one patient had a remarkably durable benefit for this poor-prognosis disease. In vitro evidence of enhanced proliferative responses to relevant tumor-associated antigens suggests that combining CTLA4 blockade with antigen-targeted therapy may warrant further investigation. Clin Cancer Res; 16(5); 1662–72

Tremelimumab (anti-CTLA4) mediates immune responses mainly by direct activation of T effector cells rather than by affecting T regulatory cells

Cytotoxic T Lymphocyte Antigen 4 (CTLA4) blockade has shown antitumor activity against common cancers. However, the exact mechanism of immune mediation by anti-CTLA4 remains to be elucidated. Further understanding of how CTLA4 blockade with tremelimumab mediates immune responses may allow a more effective selection of responsive patients. Our results show that tremelimumab enhanced the proliferative response of T effector cells (Teff) upon TCR stimulation, and abrogated Treg suppressive ability. In the presence of tremelimumab, frequencies of IL-2-secreting CD4(+) T cells and IFN-γ-secreting CD4(+) and CD8(+) T cells were increased in response to polyclonal activation and tumor antigens. Importantly, Treg frequency was not reduced in the presence of tremelimumab, and expanded Tregs in cancer patients treated with tremelimumab expressed FoxP3 with no IL-2 release, confirming them as bona fide Tregs. Taken together, this data indicates that tremelimumab induces immune responses mainly by direct activation of Teff rather than by affecting Tregs.

A Randomised Phase 2 Study of AZD2014 Versus Everolimus in Patients with VEGF-Refractory Metastatic Clear Cell Renal Cancer

BACKGROUND Everolimus is a mammalian target of rapamycin (mTOR) inhibitor used in vascular endothelial growth factor (VEGF)-refractory metastatic renal cell carcinoma (mRCC). It acts on only part of the mTOR complex (TORC1 alone). In vitro data support the use of mTOR inhibitors with broader activity (TORC1 and TORC2). OBJECTIVE The purpose of this study was to determine whether combined TORC1 and TORC2 inhibition with AZD2014 has superior activity to everolimus in VEGF-refractory clear cell mRCC. DESIGN, SETTING, AND PARTICIPANTS Patients with measurable mRCC and VEGF-refractory disease were eligible for this trial. INTERVENTION Starting in February 2013, patients were randomised (1:1) to AZD2014 (50 mg twice daily) or everolimus (10 mg once daily) until progression of disease at 10 centres across the United Kingdom. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Progression-free survival (PFS) was the primary end point and was compared using the stratified log-rank test. Secondary end points included tolerability, response rates, overall survival (OS), and pharmacokinetics (PK) analysis. The study was planned to recruit 120 patients. RESULTS AND LIMITATIONS Recruitment into the trial was stopped early (June 2014) due to lack of efficacy of AZD2014. At that point, 49 patients were randomised (26 to AZD2014 and 23 to everolimus). The PFS for AZD2014 and everolimus was 1.8 and 4.6 mo, respectively (hazard ratio: 2.8 [95% confidence interval (CI), 1.2-6.5]; p=0.01). Progression of disease as the best response to therapy was 69% for AZD2014 and 13% for everolimus (p<0.001). Grade 3-4 adverse events (AEs) occurred in 35% of AZD2014 and 48% of everolimus patients (p=0.3). Only 4% of patients stopped AZD2014 due to AEs. PK analysis suggested concentrations of AZD2014 were compatible with the therapeutic range. Final stratified OS hazard ratio at the time of trial closure (January 2015) was 3.1 (95% CI, 1.1-8.4; p<0.02). CONCLUSIONS The PFS and OS of AZD2014 were inferior to everolimus in this setting despite acceptable AE and PK profiles. PATIENT SUMMARY There is a strong rationale for testing mTOR inhibitors with a broader spectrum of activity than everolimus in metastatic clear cell renal cell carcinoma. AZD2014 is such an agent, but in this study, it was inferior to everolimus despite its attractive toxicity profile.

Intravenous delivery of oncolytic reovirus to brain tumor patients immunologically primes for subsequent checkpoint blockade

Intravenous infusion of oncolytic reovirus in patients leads to infection of brain tumors, infiltration by cytotoxic T cells, and up-regulation of PD-L1. Viruses team up with cancer immunotherapy Immune checkpoint inhibitors have shown great promise for cancer therapy, but they do not treat all cancers, and neither breast nor brain tumors are usually treatable with these drugs. However, Bourgeois-Daigneault et al. discovered a way to address this for breast cancer, and Samson et al. discovered a way to address this for brain tumors. In both cases, the authors found that oncolytic virus treatment given early, before surgical resection, alters the antitumor immune response and potentiates the effects of subsequent treatment with immune checkpoint inhibitors. Although these studies differ in the details of their methods and the immune effects induced by the oncolytic viruses, they indicate the potential of such viruses for enhancing the potential of checkpoint therapy and expanding it to new types of cancer. Immune checkpoint inhibitors, including those targeting programmed cell death protein 1 (PD-1), are reshaping cancer therapeutic strategies. Evidence suggests, however, that tumor response and patient survival are determined by tumor programmed death ligand 1 (PD-L1) expression. We hypothesized that preconditioning of the tumor immune microenvironment using targeted, virus-mediated interferon (IFN) stimulation would up-regulate tumor PD-L1 protein expression and increase cytotoxic T cell infiltration, improving the efficacy of subsequent checkpoint blockade. Oncolytic viruses (OVs) represent a promising form of cancer immunotherapy. For brain tumors, almost all studies to date have used direct intralesional injection of OV, because of the largely untested belief that intravenous administration will not deliver virus to this site. We show, in a window-of-opportunity clinical study, that intravenous infusion of oncolytic human Orthoreovirus (referred to herein as reovirus) leads to infection of tumor cells subsequently resected as part of standard clinical care, both in high-grade glioma and in brain metastases, and increases cytotoxic T cell tumor infiltration relative to patients not treated with virus. We further show that reovirus up-regulates IFN-regulated gene expression, as well as the PD-1/PD-L1 axis in tumors, via an IFN-mediated mechanism. Finally, we show that addition of PD-1 blockade to reovirus enhances systemic therapy in a preclinical glioma model. These results support the development of combined systemic immunovirotherapy strategies for the treatment of both primary and secondary tumors in the brain.

Randomized Open-Label Phase II Trial of Apitolisib (GDC-0980), a Novel Inhibitor of the PI3K/Mammalian Target of Rapamycin Pathway, Versus Everolimus in Patients With Metastatic Renal Cell Carcinoma

PURPOSE To the best of our knowledge, this study is the first to compare dual inhibition of PI3K/mammalian target of rapamycin (mTOR) by apitolisib (GDC-0980) against single inhibition of mTORC1 by everolimus in metastatic renal cell carcinoma (mRCC). PATIENTS AND METHODS Patients with clear-cell mRCC who progressed on or after vascular endothelial growth factor-targeted therapy were randomly assigned to apitolisib 40 mg once per day or to everolimus 10 mg once per day. End points included progression-free survival, safety, overall survival, and objective response rate. Biomarker assessments were conducted. RESULTS Eighty-five patients were randomly assigned. After 67 events, stratified analysis revealed that median progression-free survival was significantly shorter for apitolisib than for everolimus (3.7 v 6.1 months; hazard ratio, 2.12 [95% CI, 1.23 to 3.63; P < .01]); apitolisib was not favored in any stratification subgroup. Median overall survival was not significantly different but trended in favor of everolimus (16.5 v 22.8 months; hazard ratio, 1.77 [95% CI, 0.97 to 3.24; P = .06]). The objective response rate was 7.1% for apitolisib and 11.6% for everolimus. Patients administered apitolisib with a greater incidence of grade 3 to 4 adverse events were more likely to discontinue treatment (31% v 12% for everolimus). No drug-related deaths were observed. Apitolisib in comparison with everolimus was associated with substantially more high-grade hyperglycemia (40% v 9%) and rash (24% v 2%). Apitolisib pharmacokinetics suggested a relationship between exposure, and rash and hyperglycemia. Retrospective biomarker analyses revealed a relationship between VHL mutation status and outcome with everolimus but not with apitolisib. High hypoxia-inducible factor 1α protein expression was associated with better outcome in both arms. CONCLUSION This study demonstrated that dual PI3K/mTOR inhibition by apitolisib was less effective than was everolimus in mRCC, likely because full blockade of PI3K/mTOR signaling resulted in multiple on-target adverse events. VHL mutation and hypoxia-inducible factor 1α expression may be predictive of an mTOR inhibitor benefit, although prospective validation is required.

Evidence for Oncolytic Virotherapy: Where Have We Got to and Where Are We Going?

The last few years have seen an increased interest in immunotherapy in the treatment of malignant disease. In particular, there has been significant enthusiasm for oncolytic virotherapy, with a large amount of pre-clinical data showing promise in animal models in a wide range of tumour types. How do we move forward into the clinical setting and translate something which has such potential into meaningful clinical outcomes? Here, we review how the field of oncolytic virotherapy has developed thus far and what the future may hold.

Prime-boost using separate oncolytic viruses in combination with checkpoint blockade improves anti-tumour therapy

The anti-tumour effects associated with oncolytic virus therapy are mediated significantly through immune-mediated mechanisms, which depend both on the type of virus and the route of delivery. Here, we show that intra-tumoral oncolysis by Reovirus induced the priming of a CD8+, Th1-type anti-tumour response. By contrast, systemically delivered Vesicular Stomatitis Virus expressing a cDNA library of melanoma antigens (VSV-ASMEL) promoted a potent anti-tumour CD4+ Th17 response. Therefore, we hypothesised that combining the Reovirus-induced CD8+ T cell response, with the VSV-ASMEL CD4+ Th17 helper response, would produce enhanced anti-tumour activity. Consistent with this, priming with intra-tumoral Reovirus, followed by an intra-venous VSV-ASMEL Th17 boost, significantly improved survival of mice bearing established subcutaneous B16 melanoma tumours. We also show that combination of either therapy alone with anti-PD-1 immune checkpoint blockade augmented both the Th1 response induced by systemically delivered Reovirus in combination with GM-CSF, and also the Th17 response induced by VSV-ASMEL. Significantly, anti-PD-1 also uncovered an anti-tumour Th1 response following VSV-ASMEL treatment that was not seen in the absence of checkpoint blockade. Finally, the combination of all three treatments (priming with systemically delivered Reovirus, followed by double boosting with systemic VSV-ASMEL and anti-PD-1) significantly enhanced survival, with long-term cures, compared to any individual, or double, combination therapies, associated with strong Th1 and Th17 responses to tumour antigens. Our data show that it is possible to generate fully systemic, highly effective anti-tumour immunovirotherapy by combining oncolytic viruses, along with immune checkpoint blockade, to induce complementary mechanisms of anti-tumour immune responses.

Effect of glandular metastases on overall survival of patients with metastatic clear cell renal cell carcinoma in the antiangiogenic therapy era.

BACKGROUND Glandular metastases (GMs) (pancreas, breast, parotid, thyroid, or contralateral adrenal) are rare in metastatic clear cell renal cell carcinoma (mccRCC). In a multicenter study we have assessed outcome from mccRCC with or without GMs. PATIENTS AND METHODS Patients with mccRCC and GM or non-GM (NGM) at first presentation of mccRCC, treated at 9 European centers (5 French, 3 UK, and 1 Belgian centers) between January 2004 and October 2013, were retrospectively analyzed. Association between overall survival (OS) and site of metastases was assessed using the log-rank test for univariate analysis and the chi-square test for multivariable Cox regression. RESULTS In all, 138 patients with GM mccRCC and 420 with NGM mccRCC were included; 37.2% patients with GM had Memorial Sloan-Kettering Cancer Center (MSKCC)-favorable risk vs. 18% NGM patients; 10.7% patients with GM had MSKCC-poor risk vs. 27% NGM patients (P<0.0001). Median interval from metastases to treatment was 4.2 months (range: 0-221.3mo). Median OS was 61.5 months (51.4-81.6mo) for GM and 37.4 months (31.3-42mo) for NGM (hazard ratio [HR] = 1.7; 95% CI = 1.3-2.2, P<0.001). In univariate OS analysis, age, delay between initial diagnosis and metastases, MSKCC, bone/lung metastases, and GM or NGM group were significant parameters (P<0.001). In multivariate analysis, adjusted according to MSKCC risk group, NGM vs. GM was a strong prognostic factor (HR = 1.4; 95% CI = 1.0-1.8, P=0.026); bone or liver metastases were also significant (HR = 1.3; 95% CI = 1.1-1.7, P<0.02; HR = 1.4; 95% CI = 1.1-1.7, P<0.02, respectively). Even in patients without bone or liver metastases, GM status was significant (HR = 1.8; 95% CI = 1.2-2.7, P<0.004). CONCLUSIONS This large retrospective study shows that the presence of at least 1 GM site in development of mccRCC was associated with a significantly longer OS. The presence of GMs vs. NGM disease was an independent prognostic factor for survival irrespective of the presence or absence of bone or liver metastases. This finding could affect daily practice in which patients with mccRCC and GMs should receive more aggressive treatment with a potential for long-term survival. The causal mechanisms for this improved prognosis in GM mccRCC would be evaluated in translational studies.

Talimogene laherparepvec in the treatment of melanoma

Introduction: Metastatic melanoma continues to present a significant therapeutic challenge, with an incidence rate rising faster than that of any other cancer. The last 5 years have seen a revolution in the development of new treatments for advanced melanoma, with oncogene targeted agents and checkpoint inhibitor immunotherapies providing the first convincing evidence of a positive shift in overall survival. The role of oncolytic virotherapy in this rapidly evolving field has long been the subject of debate. However, it is with the development of Talimogene Laheparepvec (T-Vec), an intratumourally administered, genetically modified clinical herpes simplex virus-1 strain that has shown positive results in Phase III testing, that the potential for the use of OV may be realised. Areas covered: This review will outline some of the recent advances in the treatment of advanced melanoma, with a detailed overview of evidence surrounding the development of T-Vec. A literature search was conducted using the databases ‘Medline’ and ‘Pubmed’, including a subsequent manual search of references to identify papers of further relevance. Expert opinion: As the pivotal OPTiM trial concludes, we outline some of the potential new directions for T-Vec and OV therapy and evaluate the ever-increasing role these novel agents are likely to play in the future landscape of cancer immunotherapy.