T-VEC for stage IIIB-IVM1a melanoma achieves high rates of complete and durable responses and is associated with tumor load: a clinical prediction model

Recent advances in immunotherapy and its combination therapies for advanced melanoma: a review

The incidence of melanoma is increasing year by year and is highly malignant, with a poor prognosis. Its treatment has always attracted much attention. Among the more clinically applied immunotherapies are immune checkpoint inhibitors, bispecific antibodies, cancer vaccines, adoptive cell transfer therapy, and oncolytic virotherapy. With the continuous development of technology and trials, in addition to immune monotherapy, combinations of immunotherapy and radiotherapy have shown surprising efficacy. In this article, we review the research progress of immune monotherapy and combination therapy for advanced melanoma, with the aim of providing new ideas for the treatment strategy for advanced melanoma.

Intralesional and Infusional Updates for Metastatic Melanoma

Locoregionally advanced and metastatic melanoma represent a challenging clinical problem, but in the era of immune checkpoint blockade and intralesional and infusional therapies, more options are available for use. Isolated limb infusion (ILI) was first introduced in the 1990s for the management of advanced melanoma, followed by the utilization of isolated extremity perfusion (ILP). Following this, intralesional oncolytic viruses, xanthene dyes, and cytokines were introduced for the management of in-transit metastases as well as unresectable, advanced melanoma. In 2015, the Food and Drug Administration (FDA) approved the first oncolytic intralesional therapy, talimogene laherparepvec (T-VEC), for the treatment of advanced melanoma. Additionally, immune checkpoint inhibition has demonstrated efficacy in the management of advanced melanomas, and this improvement in outcomes has been extrapolated to aid in the management of in-transit metastatic disease. Finally, percutaneous hepatic perfusion (PHP), also approved by the FDA, has been reported to have a significant impact on the treatment of hepatic disease in uveal melanoma. While some of these treatments have less utility due to inferior outcomes as well as higher toxicity profiles, there are selective patient profiles for which these therapies carry a role. This review highlights intralesional and infusional therapies for the management of metastatic melanoma.

Clinical and Histological Response to Talimogene Laherparepvec Therapy in Advanced Melanoma: Impact on Overall Survival

BACKGROUND

Talimogene laherparepvec (T-VEC) is an FDA-approved oncolytic herpesvirus therapy used for unresectable stage IIIB through IV metastatic melanoma. However, the correlation between clinical complete response (cCR) and pathologic complete response (pCR) in patients treated with T-VEC is understudied.

STUDY DESIGN

We conducted a retrospective study from a prospectively maintained IRB-approved melanoma single-center database in patients treated with T-VEC from October 2015 to April 2022. Patients were categorized into 3 groups: cCR with pCR, cCR without pCR, and less than cCR. The primary endpoint was overall survival. We used descriptive statistics, chi-square tests, and Wilcoxon rank-sum tests to compare key covariates among exposure groups. We used survival analysis to compare survival curves and reported hazard ratio of death (95% CI) across exposure groups.

RESULTS

We included 116 patients with a median overall survival (interquartile range) of 22.7 (14.8-39.3) months. The majority were men (69%) and White (97.4%), with a median age of 74.5 years. More than half of patients (n = 60, 51.6%) achieved cCR. Distribution among the groups was as follows: cCR with pCR (35.3%), cCR without pCR (16.3%), and less than cCR (48.4%). Median overall survival time (interquartile range) was 26.5 (18.6-36.0) months for cCR with pCR, 22.7 (14.4-35.5) months for cCR without pCR, and 17.8 (9.2-47.0) months for less than cCR (log-rank p value = 0.0033).

CONCLUSIONS

Patients achieving cCR with pCR after T-VEC therapy have the most favorable overall survival outcomes, whereas those achieving cCR without pCR have inferior survival and those achieving less than cCR have the poorest overall survival outcomes. These findings emphasize the importance of histological confirmation and provide insights for optimizing T-VEC therapy in patients with advanced melanoma.

The efficacy and safety assessment of oncolytic virotherapies in the treatment of advanced melanoma: a systematic review and meta-analysis

BACKGROUND

The efficacy and safety of oncolytic virotherapies in the treatment of advanced melanoma still remains controversal. It is necessary to conduct quantitative evaluation on the basis of preclinical trial reports.

METHODS

Publicly available databases (PubMed, Embase, Medline, Web of Science and Cochrane Library.) and register (Clinicaltrials.gov) were searched to collect treatment outcomes of oncolytic virotherapies (including herpes simplex virus type 1 (HSV), coxsackievirus A21 (CVA21), adenovirus, poxvirus and reovirus) for advanced/unresectable melanoma. Comparisons of treatment response, adverse events (AEs) and survival analyses for different virotherapies were performed by R software based on the extracted data from eligible studies.

RESULTS

Finally, thirty-four eligible studies were analysed and HSV virotherapy had the highest average complete response (CR, 24.8%) and HSV had a slightly higher average overall response rate (ORR) than CVA21 (43.8% vs 42.6%). In the pooled results of comparing talimogene laherparepve (T-VEC) with or without GM-CSF/ICIs (immune checkpoint inhibitors) to GM-CSF/ICIs monotherapy suggested virotherapy was more efficient in subgroups CR (RR = 1.80, 95% CI [1.30; 2.51], P < 0.01), ORR (RR = 1.17, 95% CI [1.02; 1.34], P < 0.05), and DCR (RR = 1.27, 95% CI [1.15; 1.40], P < 0.01). In patients treated with T-VEC+ICIs, 2-year overall survival (12.1 ± 6.9 months) and progression-free survival (9.9 ± 6.9) were significantly longer than those treated with T-VEC alone. Furthermore, we found that AEs occurred frequently in virotherapy but decreased in a large cohort of enrolled patients, some of which, such as abdominal distension/pain, injection site pain and pruritus, were found to be positively associated with disease progression in patients treated with T-VEC monotherapy.

CONCLUSION

Given the relative safety and tolerability of oncolytic viruses, and the lack of reports of dose-limiting-dependent toxicities, more patients treated with T-VEC with or without ICIs should be added to future assessment analyses. There is still a long way to go before it can be used as a first-line therapy for patients with advanced or unresectable melanoma.

Neoadjuvant nivolumab + T-VEC combination therapy for resectable early stage or metastatic (IIIB-IVM1a) melanoma with injectable disease: study protocol of the NIVEC trial

Background

Trials investigating neoadjuvant treatment with immune checkpoint inhibitors (ICI) in patients with melanoma have shown high clinical and pathologic response rates. Treatment with talimogene laherparepvec (T-VEC), a modified herpes simplex virus type-1 (HSV-1), is approved for patients with unresectable stage IIIB-IVM1a melanoma and has the potential to make tumors more susceptible for ICI. Combination ICI and intralesional T-VEC has already been investigated in patients with unresectable stage IIIB-IV disease, however, no data is available yet on the potential benefit of this combination therapy in neoadjuvant setting.

Methods

This single center, single arm, phase II study aims to show an improved major pathologic complete response (pCR) rate, either pCR or near-pCR, up to 45% in 24 patients with resectable stage IIIB-IVM1a melanoma upon neoadjuvant combination treatment with intralesional T-VEC and systemic nivolumab (anti-PD-1 antibody). Patients will receive four courses of T-VEC up to 4 mL (first dose as seroconversion dose) and three doses of nivolumab (240 mg flatdose) every 2 weeks, followed by surgical resection in week nine. The primary endpoint of this trial is pathologic response rate. Secondary endpoints are safety, the rate of delay of surgery and event-free survival. Additionally, prognostic and predictive biomarker research and health-related quality of life evaluation will be performed.

Discussion

Intralesional T-VEC has the capacity to heighten the immune response and to elicit an abscopal effect in melanoma in combination with ICI. However, the potential clinical benefit of T-VEC plus ICI in the neoadjuvant setting remains unknown. This is the first trial investigating the efficacy and safety of neoadjuvant treatment of T-VEC and nivolumab followed by surgical resection in patients with stage IIIB-IVM1a melanoma, with the potential of high pathologic response rates and acceptable toxicity.

Trial registration

This trial was registered in the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT- number: 2019–001911-22) and the Central Committee on Research Involving Human Subjects (NL71866.000.19) on 4th June 2020.

Secondary identifying number: NCT04330430.

Dermoscopy as response evaluation tool for cutaneous malignant melanoma metastases treated with Talimogene Laherparepvec: a prospective feasibility study

BACKGROUND

Currently, the response of cutaneous melanoma metastases (CMM) to treatment with Talimogene Laherparepvec (T-VEC) is evaluated by clinical examination, macroscopic lesion photography and 3-monthly PET-CT scans. When a complete response (CR) is suspected, biopsies are taken for histopathological confirmation.

OBJECTIVES

We set out to investigate the feasibility of dermoscopy in monitoring the response to T-VEC in a pilot study.

METHODS

Six patients with CMM treated with T-VEC monotherapy were enrolled in the pilot study. Patients were treated with T-VEC according to protocol and the response was monitored with clinical examination, macroscopic lesion photography and 3-monthly PET-CT scans. For this study, 1-3 cutaneous metastases per patient were selected. Macroscopic and dermoscopic pictures of these metastases were taken at baseline, prior to each treatment with T-VEC and prior to histological biopsy. The pictures were evaluated by two investigators, using a color-based pattern classification.

RESULTS

In total 11 CMM were dermoscopically assessed, 93% was located on the extremities. Four metastases had a blue pattern, two metastases had a pink pattern, three metastases had a brown pattern and two metastases had mixed pattern. Metastases with a pink pattern harbored glomerular and arborizing vessels that diminished and vanished during treatment T-VEC, indicating CR. The remaining metastases did not show changes on a dermoscopic level that were not also seen on macroscopic level. Five patients achieved CR to T-VEC, one patient is still on treatment.

CONCLUSIONS

These results suggest that for CMM with a pink pattern, dermoscopy can provide additional information regarding the response to T-VEC. For cutaneous metastases with a blue, brown or a mixed pattern, dermoscopy did not provide additional information on top of the information obtained through physical examination and lesion photography. More studies would be needed to determine the exact role of dermoscopy in the evaluation of CMM.

Histopathological and immunological spectrum in response evaluation of talimogene laherparepvec treatment and correlation with durable response in patients with cutaneous melanoma

Talimogene laherparepvec (T-VEC) is an intralesional oncolytic virotherapy for patients with irresectable stage III-IVM1a cutaneous melanoma. Although this treatment is considered to mainly act through T cell-mediated mechanisms, prominent numbers of plasma cells after T-VEC treatment have been described. The aim was to investigate how often these plasma cells were present, whether they were relevant in the response to treatment, and if these or other histopathological features were associated with durable response to treatment. Histopathological (granulomas, perineural inflammation, etc.) and immunological features [e.g. B cells/plasma cells (CD20/CD138) and T cells (CD3,CD4,CD8)] were scored and correlated with durable tumor response [i.e. complete response (CR) persisting beyond 6 months after treatment]. Plasmacellular infiltrate was examined with next-generation sequencing and immunohistochemistry (IgG, IgM, IgA, and IgD). Plasma cells were present in all T-VEC injected biopsies from 25 patients with melanoma taken at 3-5 months after starting treatment. In patients with a durable response ( n = 12), angiocentric features and granulomas were more frequently identified compared with patients without a (durable) response ( n = 13); 75% versus 29% for angiocentric features ( P = 0.015) and 58% versus 15% for granulomas ( P = 0.041). There was a class switch of IgM to IgG with skewing to certain dominant Ig heavy chain clonotypes. An angiocentric granulomatous pattern in T-VEC injected melanoma lesions was associated with a durable CR (>6 months). Plasma cells are probably a relevant feature in the mechanism of response but were not associated with durable response.

Single agent Talimogene Laherparepvec for stage IIIB-IVM1c melanoma patients: A systematic review and meta-analysis

Single-agent Talimogene Laherparepvec (T-VEC) was developed for treatment of unresectable and injectable stage III-IV melanoma. Since its approval and reimbursement, studies have reported varying response rates. The purpose of this systematic review and meta-analysis was to investigate the efficacy and safety of T-VEC. Of 341 publications that were identified, eight studies with a total of 642 patients were included. In patients with stage IIIB-IVM1a, the pooled complete- and overall response rate (CRR and ORR) were 41% and 64%, respectively. In patients with stage IIIB-IVM1c, the pooled CRR and ORR were 30% and 44%, respectively. In patients with stage IVM1b and IVM1c, the pooled CRR and ORR were 4% and 9%, respectively. Adverse events (AEs) were seen in 41-100% of all patients and 0-11% of AEs were severe. In conclusion, single agent T-VEC achieves the highest response rates in patients with early metastatic melanoma and is well-tolerated with generally only mild toxicities.

The efficacy of immune checkpoint blockade for melanoma in-transit with or without nodal metastases - A multicenter cohort study

PURPOSE

Guidelines addressing melanoma in-transit metastasis (ITM) recommend immune checkpoint inhibitors (ICI) as a first-line treatment option, despite the fact that there are no efficacy data available from prospective trials for exclusively ITM disease. The study aims to analyze the outcome of patients with ITM treated with ICI based on data from a large cohort of patients treated at international referral clinics.

METHODS

A multicenter retrospective cohort study of patients treated between January 2015 and December 2020 from Australia, Europe, and the USA, evaluating treatment with ICI for ITM with or without nodal involvement (AJCC8 N1c, N2c, and N3c) and without distant disease (M0). Treatment was with PD-1 inhibitor (nivolumab or pembrolizumab) and/or CTLA-4 inhibitor (ipilimumab). The response was evaluated according to the RECIST criteria modified for cutaneous lesions.

RESULTS

A total of 287 patients from 21 institutions in eight countries were included. Immunotherapy was first-line treatment in 64 (22%) patients. PD-1 or CTLA-4 inhibitor monotherapy was given in 233 (81%) and 23 (8%) patients, respectively, while 31 (11%) received both in combination. The overall response rate was 56%, complete response (CR) rate was 36%, and progressive disease (PD) rate was 32%. Median PFS was ten months (95% CI 7.4-12.6 months) with a one-, two-, and five-year PFS rate of 48%, 33%, and 18%, respectively. Median MSS was not reached, and the one-, two-, and five-year MSS rates were 95%, 83%, and 71%, respectively.

CONCLUSION

Systemic immunotherapy is an effective treatment for melanoma ITM. Future studies should evaluate the role of systemic immunotherapy in the context of multimodality therapy, including locoregional treatments such as surgery, intralesional therapy, and regional therapies.

Signal pathways of melanoma and targeted therapy

Melanoma is the most lethal skin cancer that originates from the malignant transformation of melanocytes. Although melanoma has long been regarded as a cancerous malignancy with few therapeutic options, increased biological understanding and unprecedented innovations in therapies targeting mutated driver genes and immune checkpoints have substantially improved the prognosis of patients. However, the low response rate and inevitable occurrence of resistance to currently available targeted therapies have posed the obstacle in the path of melanoma management to obtain further amelioration. Therefore, it is necessary to understand the mechanisms underlying melanoma pathogenesis more comprehensively, which might lead to more substantial progress in therapeutic approaches and expand clinical options for melanoma therapy. In this review, we firstly make a brief introduction to melanoma epidemiology, clinical subtypes, risk factors, and current therapies. Then, the signal pathways orchestrating melanoma pathogenesis, including genetic mutations, key transcriptional regulators, epigenetic dysregulations, metabolic reprogramming, crucial metastasis-related signals, tumor-promoting inflammatory pathways, and pro-angiogenic factors, have been systemically reviewed and discussed. Subsequently, we outline current progresses in therapies targeting mutated driver genes and immune checkpoints, as well as the mechanisms underlying the treatment resistance. Finally, the prospects and challenges in the development of melanoma therapy, especially immunotherapy and related ongoing clinical trials, are summarized and discussed.

External Validation of a Dutch Predictive Nomogram for Complete Response to T-VEC in an Independent American Patient Cohort

PURPOSE

Talimogene Laherparepvec (T-VEC) is a modified herpes simplex virus type-1 used as intralesional immunotherapy in stage IIIB-IVM1a melanoma patients. Recently, Stahlie et al. published a predictive model for complete response (CR) to T-VEC. This study was designed to validate this model externally in an independent, American patient cohort.

METHODS

In total, 71 stage IIIB-IVM1a melanoma patients treated with T-VEC at Moffitt Cancer Center were included. A second nomogram was built incorporating the same predictive factors: tumor size (diameter of largest metastasis), type of metastases (cutaneous, subcutaneous and nodal), and number of metastases (cutoff: < 20 and > 20). Predictive accuracy was assessed through calculation of overall performance, discriminative ability, and calibration.

RESULTS

The two cohorts were similar in many clinicopathologic factors and only differing in tumor mutational status and use of systemic therapy prior to T-VEC. In the validation cohort, 37 (52%) patients showed CR, 22 (31%) partial response (PR), 2 (5.6%) stable disease (SD), and 10 (15%) progressive disease (PD). Of those who demonstrated a CR, 16 (43%) recurred. Overall performance was good (0.164), and discriminative power resulted in fair discriminative ability (0.827). The calibration curve showed slight underestimation for predicted probabilities > 0.15 and slight overestimation <0.15.

CONCLUSIONS

The original model as well as the validation model show comparable and good predictive accuracy. The validation model reinforces the conclusion that for the best response to T-VEC, it should be used early on in the course of the disease, when the tumor burden is cutaneous with smaller diameter and fewer of metastases.

Oncolytic Virotherapy for Melanoma Brain Metastases, a Potential New Treatment Paradigm?

INTRODUCTION

Melanoma brain metastases remain a devastating disease process with poor prognosis. Recently, there has been a surge in studies demonstrating the efficacy of oncolytic virotherapy for brain tumor treatment. Given their specificity and amenability to genetic modification, the authors explore the possible role of oncolytic virotherapy as a potential treatment option for patients with melanoma brain metastases.

METHODS

A comprehensive literature review including both preclinical and clinical evidence of oncolytic virotherapy for the treatment of melanoma brain metastasis was performed.

RESULTS

Oncolytic virotherapy, specifically T-VEC (Imlygic™), was approved for the treatment of melanoma in 2015. Recent clinical trials demonstrate promising anti-tumor changes in patients who have received T-VEC; however, there is little evidence for its use in metastatic brain disease based on the existing literature. To date, only two single cases utilizing virotherapy in patients with metastatic brain melanoma have been reported, specifically in patients with treatment refractory disease. Currently, there is not sufficient data to support the use of T-VEC or other viruses for intracranial metastatic melanoma. In developing a virotherapy treatment paradigm for melanoma brain metastases, several factors must be considered, including route of administration, need to bypass the blood-brain barrier, viral tumor infectivity, and risk of adverse events.

CONCLUSIONS

Evidence for oncolytic virotherapy treatment of melanoma is limited primarily to T-VEC, with a noticeable paucity of data in the literature with respect to brain tumor metastasis. Given the promising findings of virotherapy for other brain tumor types, oncolytic virotherapy has great potential to offer benefits to patients afflicted with melanoma brain metastases and warrants further investigation.