Ipilimumab and fotemustine in patients with advanced melanoma (NIBIT-M1): an open-label, single-arm phase 2 trial

Anti-cytotoxic T lymphocyte antigen-4 antibodies in melanoma

Approaches aimed at enhancement of the tumor specific response have provided proof for the rationale of immunotherapy in cancer, both in animal models and in humans. Ipilimumab, an anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) antibody, is a new generation immunotherapeutic agent that has shown activity in terms of disease free and overall survival in metastatic melanoma patients. Its use was approved by the US Food and Drug Administration in March 2011 to treat patients with late stage melanoma that has spread or that cannot be removed by surgery. The mechanism of action of CTLA-4 antibodies in the activation of an antitumor immune response and selected clinical studies of ipilimumab in advanced melanoma patients are discussed. Ipilimumab treatment has been associated with immune related adverse events due to T-cell activation and proliferation. Most of these serious adverse effects are associated with the gastrointestinal tract and include severe diarrhea and colitis. The relationship between immune related adverse events and antitumor activity associated with ipilimumab was explored in clinical studies. Potential biomarkers predictive for clinical response and survival in patients treated with anti-CTLA-4 therapy are presently under investigation. Besides the conventional patterns of response and stable disease as defined by standard Response Evaluation Criteria in Solid Tumors criteria, in subsets of patients, ipilimumab has shown patterns of delayed clinical activity which were associated with an improved overall survival. For this reason a new set of response criteria for tumor immunotherapy has been proposed, which was termed immune related response criteria. These new criteria are presently used to better analyze clinical activity of immunotherapeutic regimens. Ipilimumab is currently under investigation in combination with other treatments, such as chemotherapy, target agents, radiotherapy, and other immuno-therapeutic regimens.

The delicate balance of melanoma immunotherapy

The strategy of immune modulation for the treatment of cancer is being refined with the introduction of multiple new therapeutic agents into the clinic. Melanoma is a disease where many of these agents have demonstrated efficacy. The mechanisms of action of these agents exploit the counter-regulatory mechanisms of the immune response. However, these agents are also associated with immune-related adverse events (IRAEs), which represent tissue-specific inflammatory responses. These IRAEs highlight the delicate balance of immunologic homeostasis and, with some interventions, may occur more frequently in patients who sustain a therapeutic response. This review will discuss melanoma immunogenicity and immunotherapy. Furthermore, the spectrum and distinction between a reversible immune adverse event and autoimmunity will be highlighted.

Update on the role of ipilimumab in melanoma and first data on new combination therapies

PURPOSE OF REVIEW

This article provides an update on the therapeutic role of the monoclonal antibody ipilimumab in melanoma. Recent therapeutic combinations, as well as directions for further investigations, will also be discussed.

RECENT FINDINGS

By blocking the interaction between CTLA-4 and B7 expressed on activated T lymphocytes and antigen-presenting cells, respectively, ipilimumab inhibits negative signals that physiologically downregulate T-cell activation and exerts its therapeutic activity by upregulating the antitumor activity of T lymphocytes. Ipilimumab has been the first agent to significantly improve the survival of metastatic melanoma patients and to provide long-term benefit to a sizeable proportion of patients treated within phase II/III studies and expanded access programs. On these premises, a number of studies combining ipilimumab with cytotoxic, antiangiogenic, and targeted agents have been most recently conducted.

SUMMARY

Ipilimumab is the prototype of a growing family of 'immunomodulating antibodies' and it has demonstrated that immunotherapy will play an increasingly important role in the new treatment approaches for cancer. Combinations of chemotherapy, radiation therapy, and targeted drugs with ipilimumab indicate that additive and synergistic antitumor activity can be achieved. Most importantly, they indicate that involving the immune system is a key strategy to improve the outcome in cancer patients.

The use of systemic therapies for the treatment of brain metastases in metastatic melanoma: opportunities and unanswered questions

The development of brain metastases is common in patients with metastatic melanoma and heralds a particularly poor prognosis. The development of the immunological agent ipilimumab and targeted treatments such as the selective BRAF inhibitor vemurafenib have revolutionised the treatment of metastatic disease. Evidence from clinical trials suggest these drugs may be effective in the treatment of brain metastases from melanoma. However efficacy may be limited by a lack of penetration of the blood brain barrier (BBB) and by multi substrate efflux pumps expressed on the BBB. The role and sequencing of radiotherapy, both whole brain and stereotactic radiotherapy, is yet to be determined but combinations of radiotherapy and systemic therapies may further increase the effects of these drugs on brain metastases. Considering the impact of brain metastases on morbidity and mortality in metastatic melanoma, future research into systemic drug therapy for the treatment of brain metastases and improvements in BBB penetrance should be a priority.

Development of ipilimumab: a novel immunotherapeutic approach for the treatment of advanced melanoma

The immunotherapeutic agent ipilimumab has helped address a significant unmet need in the treatment of advanced melanoma. Ipilimumab is a fully human monoclonal antibody that targets cytotoxic T-lymphocyte antigen-4 (CTLA-4), thereby augmenting antitumor immune responses. After decades in which a number of clinical trials were conducted, ipilimumab was the first therapy to improve overall survival in a randomized, controlled phase III trial of patients with advanced melanoma. These results led to the regulatory approval of ipilimumab at 3 mg/kg for the treatment of unresectable or metastatic melanoma. More than 17,000 patients worldwide have received ipilimumab, either as a commercial drug at 3 mg/kg or in clinical trials and expanded access programs at different doses. Consistent with its proposed mechanism of action, the most common toxicities associated with ipilimumab therapy are inflammatory in nature. These immune-related adverse events were mostly reversible when effective treatment guidelines were followed. Importantly, long-term follow-up of patients who received ipilimumab in a phase III trial showed that 24% survived at least two years, and in phase II studies, a proportion of patients survived at least five years. Evaluation of ipilimumab is ongoing in the adjuvant setting for melanoma, and for advanced disease in nonsmall cell lung, small cell lung, prostate, ovarian, and gastric cancers.

Immune-suppressive properties of the tumor microenvironment

Solid tumors are more than an accumulation of cancer cells. Indeed, cancerous cells create a permissive microenvironment by exploiting non-transformed host cells. Thus, solid tumors rather resemble abnormal organs composed of the cancerous cells itself and the stroma providing the supportive framework. The stroma can be divided into the extracellular matrix consisting of proteoglycans, hyaluronic acid, and fibrous proteins, as well as stromal cells including mesenchymal and immune cells; moreover, it contains various peptide factors and metabolites. Here, we will focus on immune-modulating capacities of the tumor microenvironment.

Antitumor activity of tumor-targeted RNA replicase-based plasmid that expresses interleukin-2 in a murine melanoma model

Double-stranded RNA (dsRNA) has multiple antitumor mechanisms that may be used to control tumor growth. Previously we have shown that treatment of solid tumors with a plasmid that encodes Sindbis viral RNA replicase complex, pSIN-β, significantly inhibited the growth of tumors in mice. In the present study, we evaluated the feasibility of further improving the antitumor activity of the pSIN-β plasmid by incorporating interleukin-2 (IL2) gene into the plasmid. The resultant pSIN-IL2 plasmid was delivered to mouse melanoma cells that overexpress the sigma receptor. Here we report that the pSIN-IL2 plasmid was more effective at controlling the growth of B16 melanoma in mice when complexed with sigma receptor-targeted liposomes than with the untargeted liposomes. Importantly, the pSIN-IL2 plasmid was more effective than pSIN-β plasmid at controlling the growth of B16 melanoma in mice, and B16 tumor-bearing mice that were treated with pSIN-IL2 had an elevated number of activated CD4(+), CD8(+), and natural killer cells, as compared to those treated with pSIN-β. The RNA replicase-based, IL2-expressing plasmid may have applications in melanoma gene therapy.

Mixed response to ipilimumab in a melanoma patient with brain metastases: case report and review of the literature

Management of patients suffering from metastatic malignant melanoma and brain metastasis remains challenging in routine clinical practice. The inhibitory anti-CTLA-4 antibody ipilimumab has recently been approved as second-line therapeutic option for melanoma patients. Increasing evidence suggests distinct therapeutic activity on central nervous system metastases, although this continues to be actively debated. Here, we present the case of a patient suffering from metastatic melanoma, including symptomatic brain metastasis, who showed a partial response to ipilimumab in extracranial tumor manifestations, while the disease was progressing intracranially. Subsequently, intracranial disease progression could be managed by local irradiation. An overview of currently available literature on the efficacy of ipilimumab in melanoma patients with central nervous system metastases is provided.

Cancer testis antigen and immunotherapy

The identification of cancer testis (CT) antigens has been an important advance in determining potential targets for cancer immunotherapy. Multiple previous studies have shown that CT antigen vaccines, using both peptides and dendritic cell vaccines, can elicit clinical and immunologic responses in several different tumors. This review details the expression of melanoma antigen family A, 1 (MAGE-A1), melanoma antigen family A, 3 (MAGE-A3), and New York esophageal squamous cell carcinoma-1 (NY-ESO-1) in various malignancies, and presents our current understanding of CT antigen based immunotherapy.

Chemotherapy in the management of brain metastases: the emerging role of fotemustine for patients with melanoma and NSCLC

INTRODUCTION

An estimated 20 - 40% of cancer patients will develop brain metastases that are the most common intracranial tumors in adults. Patients with cerebral metastases represent a variegate group where selection of the most appropriate treatment depends on many patient- and disease-related factors. The impact of therapeutic option on overall survival is lacking and it is important to consider quality of life (QOL) when treating patients with brain metastases.

AREAS COVERED

A considerable proportion of patients are treated with palliative approaches such as whole-brain radiotherapy. The role of chemotherapy was limited in the past. Recently, several chemotherapeutic agents have been identified as potentially useful. This article examines the pharmacokinetics, efficacy and safety and tolerability of fotemustine (FTM) for the management of patients with cerebral metastasis from melanoma and non-small cell lung cancer (NSCLC).

EXPERT OPINION

FTM is a third-generation nitrosourea that has proved its efficacy on brain metastases of melanoma and showed promising results for the treatment of brain metastasis of NSCLC because of its ability to pass the blood-brain barrier.

Endocrine side effects induced by immune checkpoint inhibitors

CONTEXT

In recent years, progress has been made in cancer immunotherapy by the development of drugs acting as modulators of immune checkpoint proteins, such as the cytotoxic T-lymphocyte antigen-4 (CTLA4) and programmed death-1 (PD-1), two co-inhibitory receptors that are expressed on T cells upon activation. These molecules play crucial roles in maintaining immune homeostasis by down-regulating T-cell signaling, thereby preventing unbridled T-cell proliferation while maintaining tolerance to self-antigens, such as tumor-associated antigens. CTLA4 blockade through systemic administration of the CTLA4-blocking antibody ipilimumab was shown to confer significant survival benefit and prolonged stable disease in patients affected by advanced cutaneous melanoma. Other immune checkpoint inhibitors are under clinical evaluation. However, immune checkpoint blockade can lead to the breaking of immune self-tolerance, thereby inducing a novel syndrome of autoimmune/autoinflammatory side effects, designated as "immune-related adverse events," mainly including rash, colitis, hepatitis, and endocrinopathies.

DATA ACQUISITION

We searched the medical literature using the words "hypophysitis," "hypopituitarism," "thyroid," "adrenal insufficiency," and "endocrine adverse events" in association with "immune checkpoint inhibitors," "ipilimumab," "tremelimumab," "PD-1," and "PD-1-L."

EVIDENCE SYNTHESIS

The spectrum of endocrine disease experienced by patients treated with ipilimumab includes most commonly hypophysitis, more rarely thyroid disease or abnormalities in thyroid function tests, and occasionally primary adrenal insufficiency. Hypophysitis has emerged as a distinctive side effect of CTLA4-blocking antibodies, establishing a new form of autoimmune pituitary disease. This condition, if not promptly recognized, may be life-threatening (due to secondary hypoadrenalism). Hypopituitarism caused by these agents is rarely reversible, and prolonged or lifelong substitutive hormonal treatment is often required. The precise mechanism of injury to the endocrine system triggered by these drugs is yet to be fully elucidated.

CONCLUSIONS

Although reports of endocrine side effects caused by cancer immune therapy are abundant, their exact prevalence and mechanism are unclear. Well-designed correlative studies oriented to finding and validating predictive factors of autoimmune toxicity are urgently needed.

Advances in personalized targeted treatment of metastatic melanoma and non-invasive tumor monitoring

Despite extensive scientific progress in the melanoma field, treatment of advanced stage melanoma with chemotherapeutics and biotherapeutics has rarely provided response rates higher than 20%. In the past decade, targeted inhibitors have been developed for metastatic melanoma, leading to the advent of more personalized therapies of genetically characterized tumors. Here we review current melanoma treatments and emerging targeted molecular therapies. In particular we discuss the mutant BRAF inhibitors Vemurafenib and Dabrafenib, which markedly inhibit tumor growth and advance patients' overall survival. However this response is almost inevitably followed by complete tumor relapse due to drug resistance hampering the encouraging initial responses. Several mechanisms of resistance within and outside the MAPK pathway have now been uncovered and have paved the way for clinical trials of combination therapies to try and overcome tumor relapse. It is apparent that personalized treatment management will be required in this new era of targeted treatment. Circulating tumor cells (CTCs) provide an easily accessible means of monitoring patient relapse and several new approaches are available for the molecular characterization of CTCs. Thus CTCs provide a monitoring tool to evaluate treatment efficacy and early detection of drug resistance in real time. We detail here how advances in the molecular analysis of CTCs may provide insight into new avenues of approaching therapeutic options that would benefit personalized melanoma management.

Latest approved therapies for metastatic melanoma: what comes next?

Nowadays, oncogene-directed therapy and immunotherapy represent the two most promising avenues for patients with metastatic melanoma. The recent oncogene-directed therapeutic, vemurafenib, usually produces high level of tumor shrinkage and survival benefits in many patients with B-RAF (V600E) mutant melanomas, although the fast and high degrees of responses are likely short-lived. Conversely, the newly-approved immunotherapeutic, ipilimumab, produces durable responses in patients presenting CTLA-4 T-cell surface protein. Nevertheless, the possible synergy in combining these two therapeutic strategies primarily rely on the rational design of medical protocols (e.g., sequence and timing of agent administration; drug selectivity; compatibility of combined therapies i.e., adoptive T cell or agents, i.e., MEK inhibitor trametinib, PD-1 and PDL-1 blockers). Improved therapeutic protocols shall overcome therapeutic limitations such as the (i) tolerability and safety (i.e., minimal toxic side-effects); (ii) progression free survival (e.g., reduced relapse disease frequency); (iii) duration response (i.e., decreased drug resistance). Eventually, multidisciplinary approaches are still requested (e.g., genomics for personalized medicine, nanomedicine to overcome low free-drug bioavailability and targeting, systematic search of "melanoma stem cells" to enhance the prognosis and develop more valuable theranostics). In this paper, I will mainly present and discuss the latest and promising treatments for advanced cutaneous melanomas.

Phase III randomized study of fotemustine and dacarbazine versus dacarbazine with or without interferon-α in advanced malignant melanoma

BACKGROUND

The effect of the addition of fotemustine and/or interferon (IFN) to standard therapy with dacarbazine alone in patients with advanced malignant melanoma was investigated in a multicenter, randomized 2x2 factorial design trial.

METHODS

A total of 260 patients were randomly assigned to one of four treatment groups: (A) fotemustine and dacarbazine repeated on 3-week cycle; (B) same treatment as (A) plus IFN-α2b three times per week; (C) dacarbazine alone repeated on 3-week cycle; (D) same treatment as (C) plus IFN-α2b three times per week. Two comparisons were planned to assess the efficacy of fotemustine (groups A+B vs. C+D) and IFN-α2b (groups A+C vs. B+D).

RESULTS

Addition of fotemustine did not significantly improve overall survival (OS) (p=0.28) or progression-free survival (PFS) (p=0.55); Hazard ratio (HR) for OS was 0.93 (95% CI 0.71-1.21). Similarly, addition of IFN-α2b did not improve OS (p=0.68) or PFS (p=0.65); HR for OS was 0.92 (95% CI 0.70-1.20). Overall response rate was not improved by the addition of either fotemustine (p=0.87) or IFN-α2b (p=0.57). The combination of all three drugs resulted in the highest occurrence of adverse events.

CONCLUSIONS

No significant improvement in outcomes were observed with the addition of either fotemustine or IFN-α2b to dacarbazine.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01359956.

Thymosin α1 in melanoma: from the clinical trial setting to the daily practice and beyond

Thymosin α1 (Tα1) is an immunomodulatory peptide released by the thymus gland in mammals. It was first described in 1977 as a potential agent for the treatment of immune deficiencies and cancer. Among solid tumors, a number of clinical trials have investigated the activity of Tα1 in melanoma. In particular, a large randomized phase II trial that evaluated the safety and efficacy of combining Tα1 with dacarbazine and interferon alpha in metastatic melanoma patients provided the rationale for further clinical applications. The main findings emerging from clinical trials and that support the therapeutic use of Tα1 in human melanoma are summarized and discussed.

Biology of brain metastases and novel targeted therapies: time to translate the research

Brain metastases (BM) occur in 20% to 40% of patients with cancer and result in significant morbidity and poor survival. The main therapeutic options include surgery, whole brain radiotherapy, stereotactic radiosurgery and chemotherapy. Although significant progress has been made in diagnostic and therapeutic methods, the prognosis in these patients remains poor. Furthermore, the poor penetrability of chemotherapy agents through the blood brain barrier (BBB) continues to pose a challenge in the management of this disease. Preclinical evidence suggests that new targeted treatments can improve local tumor control but our clinical experience with these agents remains limited. In addition, several clinical studies with these novel agents have produced disappointing results. This review will examine the knowledge of targeted therapies in BM. The preclinical and clinical evidence of their use in BM induced by breast cancer, non-small cell lung cancer and melanoma will be presented. In addition, we will discuss the role of antiangiogenic and radiosensitising agents in the treatment of BM and the current strategies available to increase BBB permeability. A better understanding of the mechanism of action of these agents will help us to identify the best targets for testing in future clinical studies.

Dabrafenib in patients with Val600Glu or Val600Lys BRAF-mutant melanoma metastatic to the brain (BREAK-MB): a multicentre, open-label, phase 2 trial

BACKGROUND

Brain metastases are common in patients with metastatic melanoma and median overall survival from their diagnosis is typically 17-22 weeks. We assessed dabrafenib in patients with Val600Glu or Val600Lys BRAF-mutant melanoma metastatic to the brain.

METHODS

We undertook a multicentre, open-label, phase 2 trial in 24 centres in six countries. We enrolled patients with histologically confirmed Val600Glu or Val600Lys BRAF-mutant melanoma and at least one asymptomatic brain metastasis (≥5 mm and ≤40 mm in diameter). Eligible patients were aged 18 years or older, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had adequate organ function. Patients were split into two cohorts: those in cohort A had not received previous local treatment for brain metastases and those in cohort B had progressive brain metastases after previous local treatments. Patients received 150 mg oral dabrafenib twice a day until disease progression, death, or unacceptable adverse events. The primary endpoint was the proportion of patients with Val600Glu BRAF-mutant melanoma who achieved an overall intracranial response, which was defined as a complete response or partial response assessed with a modified form of Response Evaluation Criteria in Solid Tumors (RECIST 1.1). We included patients who received at least one dose of dabrafenib in efficacy and safety analyses. This study is registered with ClinicalTrials.gov, number NCT01266967.

FINDINGS

Between Feb 2, 2011, and Aug 5, 2011, we enrolled 172 patients: 89 (52%) in cohort A and 83 (48%) in cohort B. 139 (81%) had Val600Glu BRAF-mutant melanoma. 29 (39·2%, 95% CI 28·0-51·2) of 74 patients with Val600Glu BRAF-mutant melanoma in cohort A achieved an overall intracranial response, as did 20 (30·8%, 19·9-43·4) of 65 in cohort B. One (6·7%, 0·2-31·9) of 15 patients with Val600Lys BRAF-mutant melanoma achieved an overall intracranial response in cohort A, as did four (22·2%, 6·4-47·6) of 18 such patients in cohort B. Treatment-related adverse events of grade 3 or worse occurred in 38 (22%) patients. Eleven (6%) patients developed squamous-cell carcinoma (five [6%] patients in cohort A, of whom one also had keratoacanthoma; six [7%] in cohort B). Four grade 4 treatment-related adverse events occurred in cohort A: one blood amylase increase, one convulsion, one lipase increase, and one neutropenia. Two grade 4 events occurred in cohort B: one agranulocytosis and one intracranial haemorrhage. 51 (30%) patients had a serious adverse event. The three most frequent serious adverse events were pyrexia (ten [6%] patients), intracranial haemorrhage (ten [6%]; one treatment-related), and squamous-cell carcinoma (11 [6%]).

INTERPRETATION

Dabrafenib has activity and an acceptable safety profile in patients with Val600Glu BRAF-mutant melanoma and brain metastases irrespective of whether they are untreated or have been previously treated but have progressed.

FUNDING

GlaxoSmithKline.