What is new in the treatment of advanced melanoma? State of the art

Programmed cell death 1 checkpoint inhibitors in the treatment of patients with advanced melanoma

The treatment landscape of advanced melanoma has changed significantly following the discovery and marketing authorisation of immune checkpoints inhibitors. Ipilimumab (anti-CTLA-4) was the first one to be approved, and it. demonstrated long-term survival in about 20% of patients. Subsequently, anti-programmed cell death-1 (a-PD-1) antibodies (pembrolizuamb, nivolumab), inhibitors of PD-1/programmed cell death-1 ligand (PD1-L) synapse, showed higher clinical efficacy with lower toxicity comparing to ipilimumab. The highest clinical benefit in patients was observed when nivolumab and ipiliumumab were combined. However, the above strategy, due to very high toxicity, has limitations for use in all patients with advanced melanoma. Notwithstanding, patients treated with anti-PD1 beyond disease progression benefit from treatment continuation; further studies are warranted in this indication. Furthermore, patients responding to treatment with anti-PD1 will benefit from the therapy after its discontinuation. Immune checkpoint inhibitors are clinically effective regardless of BRAF mutation. Currently there is no recommendation regarding which treatment option should be selected for the treatment of the population – immunotherapy or targeted therapy with BRAF and MEK inhibitors. Randomised trials are ongoing comparing these two treatment strategies in patients with BRAF mutation. Encouraging results were observed in early phase trials in patients receiving the combination of immune and targeted therapy. Phase 3 studies are underway. Patients with elevated serum lactate dehydrogenase present poor prognosis regardless of the systemic treatment used. novel treatment strategies should probably be developed for these patients.

Diversification of Antitumour Immunity in a Patient with Metastatic Melanoma Treated with Ipilimumab and an IDO-Silenced Dendritic Cell Vaccine

Indoleamine 2,3-dioxygenase (IDO) expression in dendritic cells (DCs) inhibits T-cell activation and promotes T-cell differentiation into regulatory T-cells. Moreover, IDO expression promotes resistance to immunotherapies targeting immune checkpoints such as the cytotoxic T lymphocyte antigen-4 (CTLA-4). Here, a patient with metastatic melanoma pretreated with ipilimumab, an anti-CTLA-4 blocking antibody, was vaccinated with IDO-silenced DCs cotransfected with mRNA for survivin or hTERT tumour antigens. During vaccination, T-cell responses to survivin and hTERT tumour antigens were generated, and a certain degree of clinical benefit was achieved, with a significant reduction in lung, liver, and skin metastases, along with a better performance status. T-cell responses against MART-1 and NY-ESO-1 tumour antigens were also detected in the peripheral blood. The patient also mounted an antibody response to several melanoma proteins, indicating diversification of the antitumour immunity in this patient. The identification of such serum antibody-reacting proteins could facilitate the discovery of tumour neoantigens.

Whole Cell Therapeutic Vaccine Modified With Hyper-IL6 for Combinational Treatment of Nonresected Advanced Melanoma

Active specific immunotherapy of cancer requires an efficient induction and effector phase. The induction covers potent activation of anti-tumor response, whereas effector breaks the immunosuppression. We report efficacy of therapeutic melanoma vaccine (AGI-101H) used alone in advanced disease as a candidate for further combined treatment. In adjuvant setting in patients with resected metastases AGI-101H combined with surgery of recurring disease demonstrated long-term survival. Seventy-seven patients with nonresectable melanoma (8% IIIB, 21% IIIC, 71% IV) were enrolled. AGI-101H was administered 8× every 2 weeks, and then every month. At progression, maintenance was continued or induction was repeated and followed by maintenance. Median follow-up was 139.3 months. The median overall survival (OS) was 17.3 months; in patients with WHO 0-1 was 20.3 months. Complete response (CR) and partial response (PR) were observed in 19.4% and 9% of pts. Disease control rate was 54.5% of pts. The median CR+PR duration was 32 months. Reinduction was performed in 36.3% patients following disease progression with 46.6% of CR+PR. No grade 3/4 adverse events were observed. Treatment with AGI-101H of melanoma patients is safe and effective. AGI-101H is a good candidate for combinatorial treatment with immune check-points inhibitors or tumor hypoxia normalizators.

TRIAL REGISTRATION

EudraCT Number 2008-003373-40.

Histone deacetylase inhibitor sensitizes apoptosis-resistant melanomas to cytotoxic human T lymphocytes through regulation of TRAIL/DR5 pathway

Modern immune therapies (PD-1/PD-L1 and CTLA-4 checkpoints blockade and adoptive cell transfer) have remarkably improved the response rates of metastatic melanoma. These modalities rely on the killing potential of CTL as proximal mediator of antimelanoma responses. Mechanisms of tumor resistance to and the predominant cytotoxic pathway(s) used by melanoma-reactive CTL are important outcome determinants. We hypothesized that downmodulation of death receptors (DRs) in addition to aberrant apoptotic signaling might confer resistance to death signals delivered by CTL. To test these two hypotheses, we used an in vitro model of MART CTL-resistant melanoma sublines. TCR-transgenic and patient-derived CTLs used the TRAIL cytotoxic pathway through DR5. Furthermore, recombinant human TRAIL and drozitumab (anti-DR5 agonistic mAb) were used to explicitly verify the contribution of the DR5/TRAIL pathway in killing melanomas. CTL resistance was due to DR5 downregulation and an inverted ratio of pro- to antiapoptotic molecules, both of which were reversed by the histone deacetylase inhibitor suberoylanilide hydroxanic acid. Apoptosis negative (c-IAP-2 and Bcl-xL) and positive (DR5) regulators were potential incriminators partly regulating CTL sensitivity. These preclinical findings suggest that exposure to this chromatin remodeling drug of immune-resistant melanomas can skew toward an intracellular proapoptotic milieu, increase DR expression, and overcome acquired immune resistance.

Targeting the PD-1 pathway: a promising future for the treatment of melanoma

Advanced melanoma presents a significant therapeutic challenge to clinicians. Many therapies for metastatic melanoma are limited by low response rates, severe toxicities, and/or relatively short response duration. Cancer immunotherapies that act as immune-checkpoint inhibitors to block the localized immune suppression mechanisms utilized by tumors are undergoing development and clinical trials. A clinically relevant immune escape mechanism in melanoma is the activation of the programmed cell death-1 (PD-1) receptor on infiltrating T cells. Activating PD-1 triggers an immune checkpoint resulting in inhibition of T cells directed against melanoma antigens and prevents the immune system from combating the melanoma. In Phase I clinical trials, two anti-PD1 therapies, Nivolumab and MK-3475, that block the PD-1 receptor to enable T cell killing have demonstrated objective tumor responses in patients with advanced melanoma. The purpose of this review is to present the available clinical evidence on anti-PD-1 and anti-PD-L1 immunotherapy for the treatment of advanced melanoma. We also discuss limitations associated with anti-PD-1 therapy. The blockade of the PD-1-PD-L1 pathway has shown promising results in clinical trials and has revolutionized melanoma immunotherapy.

Aberrant apoptotic machinery confers melanoma dual resistance to BRAF(V600E) inhibitor and immune effector cells: immunosensitization by a histone deacetylase inhibitor

BRAF(V600E)-inhibitors (BRAFi; e.g., vemurafenib) and modern immune-based therapies such as PD-1/PD-L1 and CTLA-4 checkpoints blockade and adoptive cell transfer (ACT) have significantly improved the care of melanoma patients. Having these two effective (BRAFi and immunotherapy) therapies raises the question whether there is a rational biological basis for using them in combination. We developed an in vitro model to determine whether tumor resistance mechanisms to a small molecule inhibitor of a driver oncogene, and to cytotoxic T lymphocyte (CTL)- and natural killer (NK) cell-delivered apoptotic death signals were exclusive or intersecting. We generated melanoma sublines resistant to BRAFi vemurafenib and to CTL recognizing the MART-1 melanoma antigen. Vemurafenib-resistant (VemR) sublines were cross-resistant to MART CTL and NK cells indicating that a common apoptotic pathway governing tumor response to both modalities was disrupted. Pretreatment of VemR melanomas with a histone deacetylase inhibitor (HDACi) restored sensitivity to MART CTL and NK apoptosis by skewing the apoptotic gene programs towards a proapoptotic phenotype. Our in vitro findings suggest that during the course of acquisition of BRAFi resistance, melanomas develop cross-resistance to CTL- and NK-killing. Further, aberrant apoptotic pathways, amenable by an FDA-approved chromatin remodeling drug, regulate tumor resistance mechanisms to immune effector cells. These results may provide rational molecular basis for further investigations to combine these therapies clinically.