Development of Ipilimumab: Contribution to a New Paradigm for Cancer Immunotherapy

Ipilimumab associated hepatitis: imaging and clinicopathologic findings

Ipilimumab is a novel immunomodulator demonstrating promising efficacy in treatment of melanoma and other cancers. The clinical benefit from ipilimumab can be hampered by the immure-related adverse events (irAEs) caused by dysregulation of host immune system. Ipilimumab associated hepatitis is also an important irAE, however, there have been limited descriptions of its clinicopathologic and imaging characteristics. We aim to describe the clinicopathologic and imaging characteristics of 6 patients who were diagnosed as ipilimumab associated hepatitis during the ipilimumab treatment for melanoma. The clinical features of these patients were as follows: (1) severe cases with systemic symptoms and highly increased level of liver function tests (LFTs), and (2) mild asymptomatic cases with mildly increased level of LFTs. In severe cases with ALT >1,000 IU/L, imaging findings were characterized by mild hepatomegaly, periportal edema, and periportal lymphadenopathy, while mild cases showed normal imaging findings. This spectrum of imaging findings in our series was similar to that of common causes of acute hepatitis. Among 3 cases with pathologic specimen, two cases showed severe panlobular hepatitis with prominent perivenular infiltrate with endothelialitis, suggestive of predominant injury to hepatocytes, while the other case showed mild portal mononuclear infiltrate around proliferated bile ductules, suggestive of predominant injury to bile ducts. In summary, ipilimumab associated hepatitis may demonstrate variable imaging findings according to its clinical severity, and histologically may manifest either as a predominant injury to hepatocytes (acute hepatitis pattern) or as a predominant injury to bile ducts (biliary pattern).

Control of tumor-associated macrophage alternative activation by macrophage migration inhibitory factor

Tumor stromal alternatively activated macrophages are important determinants of antitumor T lymphocyte responses, intratumoral neovascularization, and metastatic dissemination. Our recent efforts to investigate the mechanism of macrophage migration inhibitory factor (MIF) in antagonizing antimelanoma immune responses reveal that macrophage-derived MIF participates in macrophage alternative activation in melanoma-bearing mice. Both peripheral and tumor-associated macrophages (TAMs) isolated from melanoma bearing MIF-deficient mice display elevated proinflammatory cytokine expression and reduced anti-inflammatory, immunosuppressive, and proangiogenic gene products compared with macrophages from tumor-bearing MIF wild-type mice. Moreover, TAMs and myeloid-derived suppressor cells from MIF-deficient mice exhibit reduced T lymphocyte immunosuppressive activities compared with those from their wild-type littermates. Corresponding with reduced tumor immunosuppression and neo-angiogenic potential by TAMs, MIF deficiency confers protection against transplantable s.c. melanoma outgrowth and melanoma lung metastatic colonization. Finally, we report for the first time, to our knowledge, that our previously discovered MIF small molecule antagonist, 4-iodo-6-phenylpyrimidine, recapitulates MIF deficiency in vitro and in vivo, and attenuates tumor-polarized macrophage alternative activation, immunosuppression, neoangiogenesis, and melanoma tumor outgrowth. These studies describe an important functional contribution by MIF to TAM alternative activation and provide justification for immunotherapeutic targeting of MIF in melanoma patients.

Integrating new therapies in the treatment of advanced melanoma

Treatments for advanced melanoma have evolved rapidly based on improved understanding of the pathways that determine T-cell responses and knowledge of growth-related mutations, which can be targeted with new classes of pharmacologic agents. The FDA approved ipilimumab and vemurafenib for advanced melanoma in 2011. Our practice is to evaluate all tumors from patients with metastatic disease for the presence of a BRAF mutation (Fig. 1). More than 20 years of follow-up show that responders to IL-2 can be cured of their melanoma. Therefore, we recommend high-dose IL-2 as first line therapy for patients with excellent functional status and normal cardiopulmonary reserve regardless of their BRAF mutation status. We use ipilimumab, which can induce durable tumor regressions and improved survival, as initial therapy for patients who refuse or are not candidates for IL-2, also regardless of their BRAF mutation status. Ipilimumab can be used as salvage therapy for patients with advanced disease after IL-2 or vemurafenib. Targeted therapies such as vemurafenib or imatinib can be offered to patients whose melanomas express the BRAF V600E or C-Kit mutations. Vemurafenib is particularly useful for patients whose disease is progressing rapidly, as clinical improvement can be obtained within days of starting therapy and response rates may be as high as 70 %. The major reason we do not recommend vemurafenib as first line treatment in all patients whose tumors have BRAF mutations is the short median duration of response of approximately 7 months. Enrollment in a clinical trial should always be considered for patients with metastatic melanoma. The clinical trial focus has changed from finding any agent with activity in melanoma, to overcoming mechanisms of resistance and enhancing the immunomodulatory activity of these new agents that confer therapeutic benefit. Selected patients can benefit from surgical resection or radiation to manage oligometastatic disease.

Specific lymphocyte subsets predict response to adoptive cell therapy using expanded autologous tumor-infiltrating lymphocytes in metastatic melanoma patients

PURPOSE

Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) is a promising treatment for metastatic melanoma unresponsive to conventional therapies. We report here on the results of an ongoing phase II clinical trial testing the efficacy of ACT using TIL in patients with metastatic melanoma and the association of specific patient clinical characteristics and the phenotypic attributes of the infused TIL with clinical response.

EXPERIMENTAL DESIGN

Altogether, 31 transiently lymphodepleted patients were treated with their expanded TIL, followed by two cycles of high-dose interleukin (IL)-2 therapy. The effects of patient clinical features and the phenotypes of the T cells infused on the clinical response were determined.

RESULTS

Overall, 15 of 31 (48.4%) patients had an objective clinical response using immune-related response criteria (irRC) with 2 patients (6.5%) having a complete response. Progression-free survival of more than 12 months was observed for 9 of 15 (60%) of the responding patients. Factors significantly associated with the objective tumor regression included a higher number of TIL infused, a higher proportion of CD8(+) T cells in the infusion product, a more differentiated effector phenotype of the CD8(+) population, and a higher frequency of CD8(+) T cells coexpressing the negative costimulation molecule "B- and T-lymphocyte attenuator" (BTLA). No significant difference in the telomere lengths of TIL between responders and nonresponders was identified.

CONCLUSION

These results indicate that the immunotherapy with expanded autologous TIL is capable of achieving durable clinical responses in patients with metastatic melanoma and that CD8(+) T cells in the infused TIL, particularly differentiated effectors cells and cells expressing BTLA, are associated with tumor regression.

Ipilimumab for advanced melanoma: a pharmacologic perspective

Ipilimumab, a fully human anti-CTLA-4 antibody, has been approved for the treatment of unresectable or metastatic melanoma based on its survival benefit demonstrated in randomized phase III studies. The current approved dosing schedule of ipilimumab is 3 mg/kg as a 90-min intravenous infusion every 3 weeks for a total of 4 doses. The immune-mediated mechanism of action of ipilimumab can result in tumor response patterns that may differ from those observed with conventional chemotherapy; therefore, revised response criteria to fully capture the spectrum of responses have been developed and are being prospectively validated. The safety profile of ipilimumab also reflects its mechanism of action and is characterized by immune-related adverse events. Although most of these events are mild, tolerable and reversible, high-grade immune-related adverse events have been observed in 15% of patients and can be potentially life-threatening if not managed appropriately. Guidelines for the management of these events emphasize thorough patient education, vigilant monitoring and prompt intervention with corticosteroids when appropriate. Ongoing research, including evaluation of ipilimumab in the adjuvant setting, investigation of its use in combination with other agents and assessment of alternative doses, will help optimize and expand the use of this innovative treatment.

Regression of human prostate cancer xenografts in mice by AMG 212/BAY2010112, a novel PSMA/CD3-Bispecific BiTE antibody cross-reactive with non-human primate antigens

For treatment of patients with prostate cancer (PCa), we developed a novel T cell-engaging (BiTE) antibody designated AMG 212 or BAY2010112 that is bispecific for prostate-specific membrane antigen (PSMA) and the CD3 epsilon subunit of the T cell receptor complex. AMG 212/BAY2010112 induced target cell-dependent activation and cytokine release of T cells, and efficiently redirected T cells for lysis of target cells. In addition to Chinese hamster ovary cells stably expressing human or cynomolgus monkey PSMA, T cells redirected by AMG 212/BAY2010112 also lysed human PCa cell lines VCaP, 22Rv1, MDA PCa 2b, C4-2, PC-3-huPSMA, and LnCaP at half maximal BiTE concentrations between 0.1 and 4 ng/mL (1.8-72 pmol/L). No lysis of PSMA-negative human PCa cell lines PC-3 and DU145 was observed. The subcutaneous (s.c.) formation of tumors from PC-3-huPSMA cells in NOD/SCID mice was significantly prevented by once daily intravenous (i.v.) injection of AMG 212/BAY2010112 at a dose level as low as 0.005 mg/kg/d. Rapid tumor shrinkage with complete remissions were observed in NOD/SCID mice bearing established s.c. 22Rv1 xenografts after repeated daily treatment with AMG 212/BAY2010112 by either the i.v. or s.c. route. Of note, 22Rv1 tumors were grown in the absence of human T cells followed by intraperitoneal injection of T cells 3 days before BiTE treatment. No effects on tumor growth were observed in the absence of human T cells or AMG 212/BAY2010112. On the basis of these preclinical results, AMG 212/BAY2010112 appears as a promising new BiTE antibody for the treatment of patients with PSMA-expressing PCa.

Characteristics and management of immunerelated adverse effects associated with ipilimumab, a new immunotherapy for metastatic melanoma

When diagnosed in its early stages, melanoma is highly treatable and associated with good long-term outcomes; however, the prognosis is much poorer for patients diagnosed with advanced or metastatic melanoma. For decades, available treatments were effective in only a few patients and associated with significant safety concerns. Ipilimumab is a novel immunotherapy which has proved to be an exciting breakthrough in the treatment of melanoma. It is the first drug approved for the treatment of melanoma by the Food and Drug Administration (FDA) which has shown a survival benefit in a randomized Phase III clinical trial. The objective of this review is to provide information on the administration, treatment responses, and expected outcomes of treatment of metastatic melanoma with the new immunotherapeutic agent, ipilimumab, a drug with a unique mechanism of action that differentiates it from current treatments. Guidelines for the management of immune-related adverse events associated with ipilimumab therapy are also presented. These stress vigilance, prompt intervention, and the use of corticosteroids as appropriate. Various ipilimumab-associated immune-related adverse events, both common (enterocolitis, dermatitis) and less frequent (hepatitis, hypophysitis), are illustrated in case studies. Nurses are uniquely positioned to provide patient and caregiver education on how this new therapy differs from traditional cytotoxic agents, to recognize the signs and symptoms of immune-related adverse events, and to report them immediately, and finally, to be aware of the patterns of response that are commonly observed in patients receiving ipilimumab therapy.

Suppressing T cell motility induced by anti-CTLA-4 monotherapy improves antitumor effects

A promising strategy for cancer immunotherapy is to disrupt key pathways regulating immune tolerance, such as cytotoxic T lymphocyte-associated protein 4 (CTLA-4). However, the determinants of response to anti-CTLA-4 mAb treatment remain incompletely understood. In murine models, anti-CTLA-4 mAbs alone fail to induce effective immune responses to poorly immunogenic tumors but are successful when combined with additional interventions, including local ionizing radiation (IR) therapy. We employed an established model based on control of a mouse carcinoma cell line to study endogenous tumor-infiltrating CD8+ T lymphocytes (TILs) following treatment with the anti-CTLA-4 mAb 9H10. Alone, 9H10 monotherapy reversed the arrest of TILs with carcinoma cells in vivo. In contrast, the combination of 9H10 and IR restored MHC class I-dependent arrest. After implantation, the carcinoma cells had reduced expression of retinoic acid early inducible-1 (RAE-1), a ligand for natural killer cell group 2D (NKG2D) receptor. We found that RAE-1 expression was induced by IR in vivo and that anti-NKG2D mAb blocked the TIL arrest induced by IR/9H10 combination therapy. These results demonstrate that anti-CTLA-4 mAb therapy induces motility of TIL and that NKG2D ligation offsets this effect to enhance TILs arrest and antitumor activity.

Ipilimumab in combination with paclitaxel and carboplatin as first-line therapy in extensive-disease-small-cell lung cancer: results from a randomized, double-blind, multicenter phase 2 trial

BACKGROUND

Ipilimumab, an anti-CTLA4 monoclonal antibody, demonstrated survival benefit in melanoma with immune-related (ir) adverse events (irAEs) managed by the protocol-defined guidelines. This phase 2 study evaluated ipilimumab+paclitaxel (Taxol)/carboplatin in extensive-disease-small-cell lung cancer (ED-SCLC).

DESIGN

Patients (n=130) with chemotherapy-naïve ED-SCLC were randomized 1: 1: 1 to receive paclitaxel (175 mg/m2)/carboplatin (area under the curve=6) with either placebo (control) or ipilimumab 10 mg/kg in two alternative regimens, concurrent ipilimumab (ipilimumab+paclitaxel/carboplatin followed by placebo+paclitaxel/carboplatin) or phased ipilimumab (placebo+paclitaxel/carboplatin followed by ipilimumab+paclitaxel/carboplatin). Treatment was administered every 3 weeks for a maximum of 18 weeks (induction), followed by maintenance ipilimumab or placebo every 12 weeks. End points included progression-free survival (PFS), irPFS, best overall response rate (BORR); irBORR, overall survival (OS), and safety.

RESULTS

Phased ipilimumab, but not concurrent ipilimumab, improved irPFS versus control [HR (hazard ratio)=0.64; P=0.03]. No improvement in PFS (HR=0.93; P=0.37) or OS (HR=0.75; P=0.13) occurred. Phased ipilimumab, concurrent ipilimumab and control, respectively, were associated with median irPFS of 6.4, 5.7 and 5.3 months; median PFS of 5.2, 3.9 and 5.2 months; median OS of 12.9, 9.1 and 9.9 months. Overall rates of grade 3/4 irAEs were 17, 21 and 9% for phased ipilimumab, concurrent ipilimumab and control, respectively.

CONCLUSION

These results suggest further investigation of ipilimumab in ED-SCLC.

Pathologic changes in ipilimumab-related hepatitis in patients with metastatic melanoma

Ipilimumab is a fully human monoclonal antibody which blocks cytotoxic T-lymphocyte antigen-4, an immune checkpoint molecule that down-regulates pathways of T-cell activation. Ipilimumab has demonstrated a statistically significant improvement in overall survival in two randomized controlled phase III trials of patients with metastatic melanoma. A main complication of ipilimumab therapy is the development of inflammatory events which can occur in various organs, including the liver (i.e., hepatitis). Hepatic injury is a concern because it can develop with little warning and may potentially be severe. We analyzed liver biopsy findings in 4 cases of ipilimumab treatment-related hepatitis and compared them to a fifth, previously reported case. All 5 patients had a histologic pattern of injury that was similar to what is observed with acute viral and autoimmune hepatitis; however, the findings are not specific and require clinicopathologic correlation. Pathologic evidence of hepatitis resolved in all 5 patients with appropriate immunosuppressive therapy. Although a relatively uncommon adverse event with ipilimumab, patients should be monitored at regular intervals for biochemical/pathological evidence of hepatitis.

Managing immune-related adverse events to ipilimumab: a nurse's guide

Ipilimumab is a U.S. Food and Drug Administration-approved novel T-cell potentiator that improves survival in metastatic melanoma. Ipilimumab blocks cytotoxic T-lymphocyte antigen-4, a negative regulator of the immune response, thus promoting T-cell activation and prolonging a patient's antitumor response. However, that action may produce a mechanism-related spectrum of immune-related adverse events (irAEs), which can become severe and life-threatening if left unrecognized and untreated. This article describes the clinical properties of ipilimumab, specifically in regard to its unique profile of irAEs. Guidelines to manage irAEs are reviewed with a particular emphasis on the contribution of nurses to patient care and education. The nurse's role in facilitating communication among the oncology team, primary practice team, patients, and caregivers is fundamental to early recognition and effective management of irAEs so that patients can continue on therapy. As a regular, ongoing presence in patient care, the oncology nurse is well placed to deliver information, assess patients' understanding of that information, and support them through their cancer experience. Checklists of irAE symptoms may be useful for patients and nurses alike. In addition, education on ipilimumab's mechanism of action and how it contributes to irAEs should form an integral part of the patient treatment plan.

Current status of immunological approaches for the treatment of prostate cancer

PURPOSE OF REVIEW

The recent Food and Drug Administration approval of sipuleucel-T for metastatic castration-resistant prostate cancer and of the anticytotoxic T-lymphocyte antigen 4 antibody (Ipilimumab) for metastatic melanoma has led to a renewed interest in immunotherapy for prostate and other cancers. Ipilimumab has entered phase III testing for prostate cancer, as has a viral-based anti-prostate-specific antigen vaccine (ProstVac-VF). Complementing these phase III studies are a number of innovative phase II studies, aimed at bringing immunotherapy forward in the setting of less advanced disease, as well as a number of interesting trials combining immunotherapy with conventional therapy for prostate cancer.

RECENT FINDINGS

Although a number of immunotherapy trials have been initiated, few mature results are available at the current time. These data are likely to mature in the setting of an increasingly complex treatment paradigm in which multiple hormonal and novel agents are available.

SUMMARY

Immunotherapy for prostate cancer represents an attractive treatment approach, with the currently available agent sipuleucel-T providing a significant survival benefit without appreciable toxicity. Novel approaches to improve the efficacy of this and other immune-active agents are currently under evaluation.

Adoptive T-cell therapy using autologous tumor-infiltrating lymphocytes for metastatic melanoma: current status and future outlook

Immunotherapy using autologous T cells has emerged to be a powerful treatment option for patients with metastatic melanoma. These include the adoptive transfer of autologous tumor-infiltrating lymphocytes (TILs), T cells transduced with high-affinity T cell receptors against major tumor antigens, and T cells transduced with chimeric antigen receptors composed of hybrid immunoglobulin light chains with endodomains of T-cell signaling molecules. Among these and other options for T-cell therapy, TILs together with high-dose interleukin 2 have had the longest clinical history with multiple clinical trials in centers across the world consistently demonstrating durable clinical response rates near 50% or more. A distinct advantage of TIL therapy making it still the T-cell therapy of choice is the broad nature of the T-cell recognition against both defined and undefined tumors antigens against all possible major histocompatibility complex, rather than the single specificity and limited major histocompatibility complex coverage of the newer T cell receptors and chimeric antigen receptor transduction technologies. In the past decade, significant inroads have been made in defining the phenotypes of T cells in TIL-mediating tumor regression. CD8+ T cells are emerging to be critical, although the exact subset of CD8+ T cells exhibiting the highest clinical activity in terms of memory and effector markers is still controversial. We present a model in which both effector-memory and more differentiated effector T cells ultimately may need to cooperate to mediate long-term tumor control in responding patients. Although TIL therapy has shown great potential to treat metastatic melanoma, a number of issues have emerged that need to be addressed to bring it more into the mainstream of melanoma care. First, we have a reached the point where a pivotal phase II or phase III trial is needed in an attempt to gain regulatory approval of TILs as standard of care. Second, improvements in how we expand TILs for therapy are needed that minimize the time the T cells are in culture and improve the memory and effector characteristics of the T cells for longer persistence and enhanced anti-tumor activity in vivo. Third, there is a critical need to identify surrogate and predictive biomarkers to better select suitable patients for TIL therapy to improve response rate and duration. Overall, the outlook for TIL therapy for melanoma is very bright. We predict that TILs will indeed emerge to become an approved treatment in the upcoming years through pivotal clinical trials. Moreover, new approaches combining TILs with targeted signaling pathway drugs, such as mutant B-RAF inhibitors, and synergistic immunomodulatory interventions enhancing T-cell costimulation and preventing negative regulation should further increase therapeutic efficacy and durable complete response rates.

Management of immune-related adverse events and kinetics of response with ipilimumab

Monoclonal antibodies directed against the immune checkpoint protein cytotoxic T-lymphocyte antigen-4 (CTLA-4; CD152)-ipilimumab and tremelimumab-have been investigated in metastatic melanoma and other cancers and have shown promising results. Recently, ipilimumab was approved by the US Food and Drug Administration for the treatment of metastatic melanoma. We review the literature on managing the adverse effects and kinetics of tumor regression with ipilimumab and provide guidelines on their management. During treatment with these antibodies, a unique set of adverse effects may occur, called immune-related adverse events (irAEs). These include rashes, which may rarely progress to life-threatening toxic epidermal necrolysis, and colitis, characterized by a mild to moderate, but occasionally also severe and persistent diarrhea. Hypophysitis, hepatitis, pancreatitis, iridocyclitis, lymphadenopathy, neuropathies, and nephritis have also been reported with ipilimumab. Early recognition of irAEs and initiation of treatment are critical to reduce the risk of sequelae. Interestingly, irAEs correlated with treatment response in some studies. Unique kinetics of response have been observed with CTLA-4 blockade with at least four patterns: (1) response in baseline lesions by week 12, with no new lesions seen; (2) stable disease, followed by a slow, steady decline in total tumor burden; (3) regression of tumor after initial increase in total tumor burden; and (4) reduction in total tumor burden during or after the appearance of new lesion(s) after week 12. We provide a detailed description of irAEs and recommendations for practicing oncologists who are managing them, along with the unusual kinetics of response associated with ipilimumab therapy.

Combining immunological and androgen-directed approaches: an emerging concept in prostate cancer immunotherapy

PURPOSE OF REVIEW

The autologous antigen-presenting cell immunotherapy, sipuleucel-T, was the first and remains the only US Food and Drug Administration-approved immunotherapy for prostate cancer. In this article, we will summarize recent clinical data on several additional immune-directed strategies, some of which have now entered phase 3 trials.

RECENT FINDINGS

Multiple studies are now testing sipuleucel-T in different disease settings and/or in combination with conventional and novel hormonal therapies. In addition, a poxviral-based vaccine has shown promise in early-phase clinical studies and has now entered phase 3 testing in men with metastatic prostate cancer. Next, a DNA vaccine has been evaluated in men with biochemically recurrent prostate cancer and has shown early signs of clinical efficacy. Finally, several studies are evaluating the role of immune checkpoint blockade using ipilimumab in pivotal phase 3 trials in prostate cancer patients with advanced disease, as well as in earlier phase studies in combination with androgen ablation.

SUMMARY

The abundance of new treatment options for men with advanced prostate cancer will challenge the role of immunotherapy in these patients. Future progress may rely on optimal combination and sequencing of various immunotherapies with androgen-directed approaches as well as with other standard prostate cancer therapies, an effort which is now just beginning.

Concordance of preclinical and clinical pharmacology and toxicology of therapeutic monoclonal antibodies and fusion proteins: cell surface targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards cell surface targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 15 currently approved mAbs and fusion proteins targeted to the cell surface. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions'; and the US Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the 15 approved biopharmaceuticals were included: abatacept; abciximab; alefacept; alemtuzumab; basiliximab; cetuximab; daclizumab; efalizumab; ipilimumab; muromonab; natalizumab; panitumumab; rituximab; tocilizumab; and trastuzumab. For statistical analysis of concordance, data from these 15 were combined with data on the approved mAbs and fusion proteins directed towards soluble targets. Good concordance with human pharmacodynamics was found for mice receiving surrogates or non-human primates (NHPs) receiving the human pharmaceutical. In contrast, there was poor concordance for human pharmacodynamics in genetically deficient mice and for human adverse effects in all three test systems. No evidence that NHPs have superior predictive value was found.

The immuno-oncology framework: Enabling a new era of cancer therapy

Developers of cancer immunotherapy have struggled for decades to achieve clinical success in using the patient's immune system to treat cancer. In the absence of a defined development paradigm for immunotherapies, conventional criteria established for chemotherapy were applied to these agents. This article summarizes the recent lessons for development of agents in the immunotherapy space, describes the systematic creation of a new clinical development paradigm for cancer immunotherapies and integrates this paradigm with the emerging methodological framework for a new clinical sub-specialty of immuno-oncology, which was driven by the collaborative work between the Cancer Immunotherapy Consortium (CIC) of the Cancer Research Institute in the US and the Association for Cancer Immunotherapy (CIMT) in Europe. This new framework provides a better defined development path and a foundation for more reproducible success of future therapies.

Ipilimumab in combination with paclitaxel and carboplatin as first-line treatment in stage IIIB/IV non-small-cell lung cancer: results from a randomized, double-blind, multicenter phase II study

PURPOSE

Ipilimumab, which is an anti-cytotoxic T-cell lymphocyte-4 monoclonal antibody, showed a survival benefit in melanoma with adverse events (AEs) managed by protocol-defined guidelines. A phase II study in lung cancer assessed the activity of ipilimumab plus paclitaxel and carboplatin.

PATIENTS AND METHODS

Patients (N = 204) with chemotherapy-naive non-small-cell lung cancer (NSCLC) were randomly assigned 1:1:1 to receive paclitaxel (175 mg/m(2)) and carboplatin (area under the curve, 6) with either placebo (control) or ipilimumab in one of the following two regimens: concurrent ipilimumab (four doses of ipilimumab plus paclitaxel and carboplatin followed by two doses of placebo plus paclitaxel and carboplatin) or phased ipilimumab (two doses of placebo plus paclitaxel and carboplatin followed by four doses of ipilimumab plus paclitaxel and carboplatin).Treatment was administered intravenously every 3 weeks for ≤ 18 weeks (induction). Eligible patients continued ipilimumab or placebo every 12 weeks as maintenance therapy. Response was assessed by using immune-related response criteria and modified WHO criteria. The primary end point was immune-related progression-free survival (irPFS). Other end points were progression-free survival (PFS), best overall response rate (BORR), immune-related BORR (irBORR), overall survival (OS), and safety.

RESULTS

The study met its primary end point of improved irPFS for phased ipilimumab versus the control (hazard ratio [HR], 0.72; P = .05), but not for concurrent ipilimumab (HR, 0.81; P = .13). Phased ipilimumab also improved PFS according to modified WHO criteria (HR, 0.69; P = .02). Phased ipilimumab, concurrent ipilimumab, and control treatments were associated with a median irPFS of 5.7, 5.5, and 4.6 months, respectively, a median PFS of 5.1, 4.1, and 4.2 months, respectively, an irBORR of 32%, 21% and 18%, respectively, a BORR of 32%, 21% and 14%, respectively, and a median OS of 12.2, 9.7, and 8.3 months. Overall rates of grade 3 and 4 immune-related AEs were 15%, 20%, and 6% for phased ipilimumab, concurrent ipilimumab, and the control, respectively. Two patients (concurrent, one patient; control, one patient) died from treatment-related toxicity.

CONCLUSION

Phased ipilimumab plus paclitaxel and carboplatin improved irPFS and PFS, which supports additional investigation of ipilimumab in NSCLC.

Sub-lethal irradiation of human colorectal tumor cells imparts enhanced and sustained susceptibility to multiple death receptor signaling pathways

Background

Death receptors (DR) of the TNF family function as anti-tumor immune effector molecules. Tumor cells, however, often exhibit DR-signaling resistance. Previous studies indicate that radiation can modify gene expression within tumor cells and increase tumor cell sensitivity to immune attack. The aim of this study is to investigate the synergistic effect of sub-lethal doses of ionizing radiation in sensitizing colorectal carcinoma cells to death receptor-mediated apoptosis.

Methodology/Principal Findings

The ability of radiation to modulate the expression of multiple death receptors (Fas/CD95, TRAILR1/DR4, TRAILR2/DR5, TNF-R1 and LTβR) was examined in colorectal tumor cells. The functional significance of sub-lethal doses of radiation in enhancing tumor cell susceptibility to DR-induced apoptosis was determined by in vitro functional sensitivity assays. The longevity of these changes and the underlying molecular mechanism of irradiation in sensitizing diverse colorectal carcinoma cells to death receptor-mediated apoptosis were also examined. We found that radiation increased surface expression of Fas, DR4 and DR5 but not LTβR or TNF-R1 in these cells. Increased expression of DRs was observed 2 days post-irradiation and remained elevated 7-days post irradiation. Sub-lethal tumor cell irradiation alone exhibited minimal cell death, but effectively sensitized three of three colorectal carcinoma cells to both TRAIL and Fas-induced apoptosis, but not LTβR-induced death. Furthermore, radiation-enhanced Fas and TRAIL-induced cell death lasted as long as 5-days post-irradiation. Specific analysis of intracellular sensitizers to apoptosis indicated that while radiation did reduce Bcl-X_L and c-FLIP protein expression, this reduction did not correlate with the radiation-enhanced sensitivity to Fas and/or TRAIL mediated apoptosis among the three cell types.

Conclusions/Significance

Irradiation of tumor cells can overcome Fas and TRAIL resistance that is long lasting. Overall, results of these investigations suggest that non-lethal doses of radiation can be used to make human tumors more amenable to attack by anti-tumor effector molecules and cells.

New approaches to the treatment of pancreatic cancer: from tumor-directed therapy to immunotherapy

The development of novel therapeutic strategies for pancreatic adenocarcinoma (PAC) has traditionally been considered particularly challenging for clinical and laboratory investigators due to its aggressive underlying biology and inherent resistance to currently available therapies. More recently, however, advances have been made in the identification of promising therapeutic targets for intervention, along with several key insights into the complex sequence of genetic alterations involved in the evolution of PAC from premalignant precursor lesion to malignant cells with metastatic potential. FOLFIRINOX (5-fluorouracil/leucovorin/irinotecan/oxaliplatin) has recently been identified as a combination cytotoxic therapy associated with a significant survival benefit over single-agent gemcitabine in good performance status patients with advanced disease; it is hoped that a similar benefit will be seen in planned trials of FOLFIRINOX as perioperative therapy. The success of immune therapy with the anti-cytotoxic T-lymphocyte antigen-4 antibody ipilimumab in advanced melanoma has spurred interest in the development of vaccines and immune therapies for other solid tumors. Certainly, the concept of harnessing the power of the immune system for cancer treatment is an attractive concept to patients and clinicians alike. Herein we discuss recent advances in the development of novel therapeutic approaches to PAC, focusing in particular on recent developments in immune and vaccine therapy.

Roles of the immune system in skin cancer

Over the past several decades, there has been increasing interest in understanding the roles of the immune system in the development and progression of cancer. The importance of the immune system in human skin cancer has been long recognized based primarily upon the increased incidence of skin cancers in organ transplant recipients and mechanisms of ultraviolet (UV) radiation-mediated immunomodulation. In this review, we integrate multiple lines of evidence highlighting the roles of the immune system in skin cancer. First, we discuss the concepts of cancer immunosurveillance and immunoediting as they might relate to human skin cancers. We then describe the clinical and molecular mechanisms of skin cancer development and progression in the contexts of therapeutic immunosuppression in organ transplant recipients, viral oncogenesis, and UV radiation-induced immunomodulation with a primary focus on basal cell carcinoma and squamous cell carcinoma. The clinical evidence supporting expanding roles for immunotherapy is also described. Finally, we discuss recent research examining the functions of particular immune cell subsets in skin cancer and how they might contribute to both antitumour and protumour effects. A better understanding of the biological mechanisms of cancer immunosurveillance holds the promise of enabling better therapies.

Clinical trials of vaccines for immunotherapy in pancreatic cancer

A greater understanding of the molecular events that trigger oncogenesis and events that negatively regulate immune responses has allowed for the development of targeted therapies with specific vaccines to match tumor antigens coupled with immunotherapy specifically directed against that tumor's immunosuppressive microenvironment. In order to be effective, vaccine therapies need to both expand the immune response to tumors and overcome immunosuppressive microenvironments therein. Specifically, targeted therapy must be personalized for each cancer patient. While the idea of personalized targeted therapy may seem like a daunting task, it may not be that difficult as it could involve a relatively simple genetic test to identify gene mutations and additional immunohistochemical staining of tumors with antibodies directed against markers of negative immune regulation. The additional cost to personalize cancer therapy with these diagnostic tests is relatively small in comparison to the cost afforded to our healthcare system when inappropriate targeting therapies are administered to patients whose tumors do not express the targets of either the vaccine or the immune modulator. Despite the large cost, cancer patients whose tumors lack the targets of these therapies often receive no benefit from the therapy. The most illogical approach is to develop a study design and perform clinical trials of potential novel targeting drugs without knowledge or confirmation that the patients' tumors express the targets. Current cancer trials for pancreatic cancer patients are discussed in this article.

Ipilimumab: an anti-CTLA-4 antibody for metastatic melanoma

Ipilimumab (MDX-010, Yervoy; Bristol-Myers Squibb), a fully human monoclonal antibody against CTL antigen 4 (CTLA-4), was recently approved by the U.S. Food and Drug Administration (FDA) for the treatment of metastatic melanoma. In both early- and late-phase trials, ipilimumab has shown consistent activity against melanoma. For example, in a randomized phase III trial that enrolled patients with previously treated metastatic disease, ipilimumab, with or without a peptide vaccine, improved overall survival: Median overall survival was 10.1 and 10.0 months in the ipilimumab and ipilimumab plus vaccine arms, respectively, versus 6.4 months in the vaccine-alone group (hazard ratio, 0.68; P ≤ 0.003). Serious (grade 3-5) immune-related adverse events occurred in 10% to 15% of patients. Thus, although it provides a clear survival benefit, ipilimumab administration requires careful patient monitoring and sometimes necessitates treatment with immune-suppressive therapy. Here, we review the mechanism of action, preclinical data, and multiple clinical trials that led to FDA approval of ipilimumab for metastatic melanoma.

Camouflage and sabotage: tumor escape from the immune system

The field of tumor immunology has made great progress in understanding tumor immune interactions. As a consequence a number of immuno-therapeutic approaches have been successfully introduced into the clinic and a large number of promising therapeutic strategies are investigated in ongoing clinical trials. Evaluation of anti-tumor immunity in such trials as well as in animal models has shown that tumor escape from immune recognition and tumor-mediated suppression of anti-tumor immunity can pose a significant obstacle to successful cancer therapy. Here, we review mechanisms of tumor immune escape and immune-subversion with a focus on the research interests in our laboratory: loss of MHC class I on tumor cells, increased oxidative stress, recruitment of myeloid-derived suppressor cells, and regulatory T cells.

Current status of immunological therapies for prostate cancer

PURPOSE OF REVIEW

Considerable progress has been made in prostate cancer immunotherapy over the last year, and two agents have completed phase III testing. This review will discuss the most promising immune-directed strategies in development for prostate cancer, outlining interventions that mitigate tumor-induced tolerance and highlighting several combination immunotherapy approaches.

RECENT FINDINGS

A pivotal phase III study using Sipuleucel-T, an autologous prostatic acid phosphatase (PAP)-loaded dendritic cell immunotherapy, in men with metastatic castration-resistant prostate cancer (CRPC) demonstrated a survival advantage over placebo. By contrast, two phase III studies of GVAX, an allogeneic tumor cell vaccine, in a similar patient population failed to show a survival benefit of GVAX or GVAX/docetaxel over standard docetaxel/prednisone. Other strategies currently in clinical development include the ProstVac poxviral vaccine, a PAP-encoding DNA vaccine, and immune checkpoint inhibitory approaches.

SUMMARY

Although Sipuleucel-T may receive FDA approval for patients with metastatic CRPC, challenges remain in identifying immunotherapy strategies that overcome immune tolerance, especially when disease burden is substantial. An emerging paradigm focuses on using immunotherapy together with checkpoint antagonists or in combination with conventional therapies in patients with early-stage disease. Such approaches are likely to yield optimal results, but must carefully be explored in well designed phase II studies before moving forward.