Elizabeth I. Buchbinder

An immunogenic personal neoantigen vaccine for patients with melanoma

Effective anti-tumour immunity in humans has been associated with the presence of T cells directed at cancer neoantigens, a class of HLA-bound peptides that arise from tumour-specific mutations. They are highly immunogenic because they are not present in normal tissues and hence bypass central thymic tolerance. Although neoantigens were long-envisioned as optimal targets for an anti-tumour immune response, their systematic discovery and evaluation only became feasible with the recent availability of massively parallel sequencing for detection of all coding mutations within tumours, and of machine learning approaches to reliably predict those mutated peptides with high-affinity binding of autologous human leukocyte antigen (HLA) molecules. We hypothesized that vaccination with neoantigens can both expand pre-existing neoantigen-specific T-cell populations and induce a broader repertoire of new T-cell specificities in cancer patients, tipping the intra-tumoural balance in favour of enhanced tumour control. Here we demonstrate the feasibility, safety, and immunogenicity of a vaccine that targets up to 20 predicted personal tumour neoantigens. Vaccine-induced polyfunctional CD4+ and CD8+ T cells targeted 58 (60%) and 15 (16%) of the 97 unique neoantigens used across patients, respectively. These T cells discriminated mutated from wild-type antigens, and in some cases directly recognized autologous tumour. Of six vaccinated patients, four had no recurrence at 25 months after vaccination, while two with recurrent disease were subsequently treated with anti-PD-1 (anti-programmed cell death-1) therapy and experienced complete tumour regression, with expansion of the repertoire of neoantigen-specific T cells. These data provide a strong rationale for further development of this approach, alone and in combination with checkpoint blockade or other immunotherapies.

CTLA-4 and PD-1 Pathways: Similarities, Differences, and Implications of Their Inhibition

The cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4) and programmed death 1 (PD-1) immune checkpoints are negative regulators of T-cell immune function. Inhibition of these targets, resulting in increased activation of the immune system, has led to new immunotherapies for melanoma, non–small cell lung cancer, and other cancers. Ipilimumab, an inhibitor of CTLA-4, is approved for the treatment of advanced or unresectable melanoma. Nivolumab and pembrolizumab, both PD-1 inhibitors, are approved to treat patients with advanced or metastatic melanoma and patients with metastatic, refractory non-small cell lung cancer. In addition the combination of ipilimumab and nivolumab has been approved in patients with BRAF WT metastatic or unresectable melanoma. The roles of CTLA-4 and PD-1 in inhibiting immune responses, including antitumor responses, are largely distinct. CTLA-4 is thought to regulate T-cell proliferation early in an immune response, primarily in lymph nodes, whereas PD-1 suppresses T cells later in an immune response, primarily in peripheral tissues. The clinical profiles of immuno-oncology agents inhibiting these 2 checkpoints may vary based on their mechanistic differences. This article provides an overview of the CTLA-4 and PD-1 pathways and implications of their inhibition in cancer therapy.

Ipilimumab Therapy in Patients With Advanced Melanoma and Preexisting Autoimmune Disorders

IMPORTANCE Ipilimumab and other immune therapies are effective treatment options for patients with advanced melanoma but cause frequent immune-related toxic effects. Autoimmune diseases are common, and the safety and efficacy of ipilimumab therapy in patients with preexisting autoimmune disorders is not known. OBJECTIVE To determine the safety and efficacy of ipilimumab therapy in patients with advanced melanoma with preexisting autoimmune disorders. DESIGN, SETTING, AND PARTICIPANTS Retrospective review of patients with advanced melanoma and preexisting autoimmune disorders who received ipilimumab at 9 academic tertiary referral centers from January 1, 2012, through August 1, 2015. The data analysis was performed on August 24, 2015. EXPOSURE Ipilimumab therapy. MAIN OUTCOMES AND MEASURES Safety, in terms of frequency of autoimmune flares and conventional immune-related adverse events (irAEs), and efficacy, in terms of response rates and overall survival, were evaluated descriptively. RESULTS Of the 30 patients who received ipilimumab (17 [57%] male; median [range] age, 59.5 [30-80] y), 6 had rheumatoid arthritis, 5 had psoriasis, 6 had inflammatory bowel disease, 2 had systemic lupus erythematosus, 2 had multiple sclerosis, 2 had autoimmune thyroiditis, and 7 had other conditions. Thirteen patients (43%) were receiving immunosuppressive therapy at the time of initiation of ipilimumab therapy, most commonly low-dose prednisone or hydroxychloroquine. With ipilimumab treatment, 8 patients (27%) experienced exacerbations of their autoimmune condition necessitating systemic treatment; all were managed with corticosteroids. Conventional grade 3 to 5 irAEs occurred in 10 patients (33%) and were reversible with corticosteroids or with infliximab therapy in 2 cases. One patient with baseline psoriasis died of presumed immune-related colitis after a 1-week delay prior to reporting symptoms. Fifteen patients (50%) had neither autoimmune disease flares nor irAEs. Six patients experienced an objective response (20%), including 1 with a durable complete response. CONCLUSIONS AND RELEVANCE To our knowledge, this is the largest series of patients with preexisting autoimmune disease treated with immune checkpoint inhibitors. Ipilimumab was clinically active and was associated with exacerbations of autoimmune disease and conventional ipilimumab-induced irAEs that were readily manageable with standard therapies when started in a timely fashion. Ipilimumab therapy may be considered in this setting with vigilant clinical monitoring.

Induction gemcitabine and stereotactic body radiotherapy for locally advanced nonmetastatic pancreas cancer.

PURPOSE Stereotactic body radiotherapy (SBRT) has been used successfully to treat patients with locally advanced pancreas cancer. However, many patients develop metastatic disease soon after diagnosis and may receive little benefit from such therapy. We therefore retrospectively analyzed a planned strategy of initial chemotherapy with restaging and then treatment for those patients with no evidence of metastatic progression with SBRT. METHODS AND MATERIALS Forty-seven patients received gemcitabine (1,000 mg/m(2) per week for 3 weeks then 1 week off) until tolerance, at least six cycles, or progression. Patients without metastases after two cycles were treated with SBRT (tolerance-based dose of 24-36 Gy in 3 fractions) between the third and fourth cycles without interrupting the chemotherapy cycles. RESULTS Eight of the 47 patients (17%) were found to have metastatic disease after two cycles of gemcitabine; the remaining 39 patients received SBRT. The median follow-up for survivors was 21 months (range, 6-36 months). The median overall survival for all patients who received SBRT was 20 months, and the median progression-free survival was 15 months. The local control rate was 85% (33 of 39 patients); and 54% of patients (21 of 39) developed metastases. Late Grade III toxicities such as GI bleeding and obstruction were observed in 9% (3/39) of patients. CONCLUSION For patients with locally advanced pancreas cancer, this strategy uses local therapy for those who are most likely to benefit from it and spares those patients with early metastatic progression from treatment. SBRT delivers such local therapy safely with minimal interruption to systemic chemotherapy, thereby potentially improving the outcome in these patients.

Sequential administration of nivolumab and ipilimumab with a planned switch in patients with advanced melanoma (CheckMate 064): an open-label, randomised, phase 2 trial

BACKGROUND Concurrent administration of the immune checkpoint inhibitors nivolumab and ipilimumab has shown greater efficacy than either agent alone in patients with advanced melanoma, albeit with more high-grade adverse events. We assessed whether sequential administration of nivolumab followed by ipilimumab, or the reverse sequence, could improve safety without compromising efficacy. METHODS We did this randomised, open-label, phase 2 study at nine academic medical centres in the USA. Eligible patients (aged ≥18 years) with unresectable stage III or IV melanoma (treatment-naive or who had progressed after no more than one previous systemic therapy, with an Eastern Cooperative Oncology Group performance status of 0 or 1) were randomly assigned (1:1) to induction with intravenous nivolumab 3 mg/kg every 2 weeks for six doses followed by a planned switch to intravenous ipilimumab 3 mg/kg every 3 weeks for four doses, or the reverse sequence. Randomisation was done by an independent interactive voice response system with a permuted block schedule (block size four) without stratification factors. After induction, both groups received intravenous nivolumab 3 mg/kg every 2 weeks until progression or unacceptable toxicity. The primary endpoint was treatment-related grade 3-5 adverse events until the end of the induction period (week 25), analysed in the as-treated population. Secondary endpoints were the proportion of patients who achieved a response at week 25 and disease progression at weeks 13 and 25. Overall survival was a prespecified exploratory endpoint. This study is registered with ClinicalTrials.gov, number NCT01783938, and is ongoing but no longer enrolling patients. FINDINGS Between April 30, 2013, and July 21, 2014, 140 patients were enrolled and randomly assigned to nivolumab followed by ipilimumab (n=70) or to the reverse sequence of ipilimumab followed by nivolumab (n=70), of whom 68 and 70 patients, respectively, received at least one dose of study drug and were included in the analyses. The frequencies of treatment-related grade 3-5 adverse events up to week 25 were similar in the nivolumab followed by ipilimumab group (34 [50%; 95% CI 37·6-62·4] of 68 patients) and in the ipilimumab followed by nivolumab group (30 [43%; 31·1-55·3] of 70 patients). The most common treatment-related grade 3-4 adverse events during the whole study period were colitis (ten [15%]) in the nivolumab followed by ipilimumab group vs 14 [20%] in the reverse sequence group), increased lipase (ten [15%] vs 12 [17%]), and diarrhoea (eight [12%] vs five [7%]). No treatment-related deaths occurred. The proportion of patients with a response at week 25 was higher with nivolumab followed by ipilimumab than with the reverse sequence (28 [41%; 95% CI 29·4-53·8] vs 14 [20%; 11·4-31·3]). Progression was reported in 26 (38%; 95% CI 26·7-50·8) patients in the nivolumab followed by ipilimumab group and 43 (61%; 49·0-72·8) patients in the reverse sequence group at week 13 and in 26 (38%; 26·7-50·8) and 42 (60%; 47·6-71·5) patients at week 25, respectively. After a median follow-up of 19·8 months (IQR 12·8-25·7), median overall survival was not reached in the nivolumab followed by ipilimumab group (95% CI 23·7-not reached), whereas over a median follow-up of 14·7 months (IQR 5·6-23·9) in the ipilimumab followed by nivolumab group, median overall survival was 16·9 months (95% CI 9·2-26·5; HR 0·48 [95% CI 0·29-0·80]). A higher proportion of patients in the nivolumab followed by ipilimumab group achieved 12-month overall survival than in the ipilimumab followed by nivolumab group (76%; 95% CI 64-85 vs 54%; 42-65). INTERPRETATION Nivolumab followed by ipilimumab appears to be a more clinically beneficial option compared with the reverse sequence, albeit with a higher frequency of adverse events. FUNDING Bristol-Myers Squibb.

PREDICTION AND PREVENTION OF THROMBOEMBOLIC EVENTS WITH ENOXAPARIN IN CANCER PATIENTS WITH ELEVATED TISSUE FACTOR-BEARING MICROPARTICLES: A RANDOMIZED-CONTROLLED PHASE II TRIAL (THE MICROTEC STUDY)

Elevated levels of circulating tissue factor‐bearing microparticles (TFMP) have been associated with an increased risk of developing venous thromboembolism (VTE) in cancer patients. We performed a randomized phase II study to evaluate the cumulative incidence of VTE in advanced cancer patients with lower levels of TFMP not receiving thromboprophylaxis and those with higher levels of circulating TFMP randomized to enoxaparin or observation. The cumulative incidence of VTE at 2 months in the higher TFMP group randomized to enoxaparin (N = 23) was 5·6% while the higher TFMP group observation arm (N = 11) was 27·3% (Gray test P = 0·06). The cumulative incidence of VTE in the low TFMP was 7·2% (N = 32). No major haemorrhages were observed in the enoxaparin arm. The median survival for patients with higher levels of TFMP followed by observation was 11·8 months compared with 17·8 months on enoxaparin (P = 0·58). In a prospective randomized trial, increased numbers of circulating TFMP detected by impedance flow cytometry identified cancer patients with a high incidence of VTE. Enoxaparin demonstrated a clear trend towards reducing the rate of VTE in patients with elevated levels of TFMP, with an overall rate of VTE similar in magnitude to the lower TFMP group.

Inhibition of Immune Checkpoints and Vascular Endothelial Growth Factor as Combination Therapy for Metastatic Melanoma: An Overview of Rationale, Preclinical Evidence, and Initial Clinical Data.

The role of angiogenesis as a mediator of immune regulation in the tumor microenvironment has recently come into focus. Furthermore, emerging evidence indicates that immunotherapy can lead to immune-mediated vasculopathy in the tumor, suggesting that the tumor vasculature may be an important interface between the tumor-directed immune response and the cancer itself. The advent of immune checkpoint inhibition as an effective immunotherapeutic strategy for many cancers has led to a better understanding of this interface. While the inhibition of angiogenesis through targeting of vascular endothelial growth factor (VEGF) has been used successfully for the treatment of cancer for many years, the mechanisms of its anti-tumor activity remain poorly understood. Initial studies of the complex relationship between angiogenesis, VEGF signaling and the immune system suggest that the combination of immune checkpoint blockade with angiogenesis inhibition has potential. While the majority of this work has been performed in metastatic melanoma, immunotherapy is rapidly showing promise in a broad range of malignancies and efforts to enhance immunotherapy will broadly impact the future of oncology. Here, we review the preclinical rationale and clinical investigations of combined angiogenesis inhibition and immunotherapy/immune checkpoint inhibition as a potentially promising combinatorial approach for cancer treatment.

Cytotoxic T lymphocyte antigen-4 and immune checkpoint blockade

The relationship between cancer and the immune system is complex and provides unique therapeutic opportunities. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is a regulatory molecule that suppresses T cell effector function following initial activation by costimulatory signals. Fully human monoclonal antibodies targeting CTLA-4 have been shown to increase T cell function and antitumor responses in patients with advanced metastatic melanoma. Responses observed with such immune checkpoint therapy can follow a different pattern from that seen with cytotoxic chemotherapy or targeted therapy and may continue after therapy is discontinued. In addition, the toxicities that are associated with anti-CTLA-4 therapy may differ from those of conventional therapies and consist of inflammatory events in parts of the body that do not contain cancerous cells. Early recognition of these inflammatory events and intervention is important, and the identification of predictive biomarkers continues to be an unfulfilled need in the field of immunotherapy. Combinatorial approaches with targeted therapies, radiation therapy, chemotherapy, or other immune checkpoint agonists/antagonists have the potential to increase the efficacy of CTLA-4 blockade.

Melanoma in 2015: Immune-checkpoint blockade — durable cancer control

In 2015, advances in immunotherapy for metastatic melanoma have come to fruition, with phase III data supporting the combination of ipilimumab and nivolumab as first-line therapy. Understanding the mechanisms involved in an effective antitumour immune response are now key to further advances. Several studies published in 2015 have increased our understanding of the complex relationships that exist between our immune system and malignancy.

Characterizing the clinical benefit of ipilimumab in patients who progressed on high-dose IL-2.

Ipilimumab improves overall survival (OS) in patients with metastatic melanoma including those previously treated with high-dose interleukin-2 (HD IL-2). The primary objective of this study was to determine if clinical response or progression-free survival (PFS) to HD IL-2 could predict benefit to subsequent ipilimumab. The secondary objective was to further characterize the clinical benefit of ipilimumab in patients who have progressed on HD IL-2. We reviewed the records of all patients with metastatic melanoma who received HD IL-2 at MD Anderson Cancer Center or Beth Israel Deaconess Medical Center from 2003 to 2009 and further identified patients who also received ipilimumab after progressing on HD IL-2. OS to ipilimumab was calculated from the first dose of ipilimumab, determined by Kaplan-Meier analysis, and was compared in patients based on their prior clinical response and PFS to HD IL-2 using the log-rank test. Patients were grouped based on their prior response to HD IL-2 as follows: complete response and partial response, stable disease, and progressive disease. Patients were also grouped and compared by prior PFS to HD IL-2 in >60 days versus ⩽60 days. A total of 208 patients with melanoma were treated with HD IL-2, 130 (63%) received additional systemic therapy after confirmed disease progression, and 48 (23%) received ipilimumab. The clinical benefit of ipilimumab was similar to previously published results (OS, 12.0 mo; PFS, 2.5 mo; response rate, 16.7%). Prior clinical response or PFS to HD IL-2 did not predict benefit to subsequent ipilimumab. Prospective trials of HD IL-2 followed by ipilimumab could potentially identify patients most likely to benefit from a sequential approach of HD IL-2 followed by ipilimumab.