Does pegylated interferon alpha-2b confer additional benefit in the adjuvant treatment of high-risk melanoma?

Vaccines, adjuvants and autoimmunity

Vaccines and autoimmunity are linked fields. Vaccine efficacy is based on whether host immune response against an antigen can elicit a memory T-cell response over time. Although the described side effects thus far have been mostly transient and acute, vaccines are able to elicit the immune system towards an autoimmune reaction. The diagnosis of a definite autoimmune disease and the occurrence of fatal outcome post-vaccination have been less frequently reported. Since vaccines are given to previously healthy hosts, who may have never developed the disease had they not been immunized, adverse events should be carefully accessed and evaluated even if they represent a limited number of occurrences. In this review of the literature, there is evidence of vaccine-induced autoimmunity and adjuvant-induced autoimmunity in both experimental models as well as human patients. Adjuvants and infectious agents may exert their immune-enhancing effects through various functional activities, encompassed by the adjuvant effect. These mechanisms are shared by different conditions triggered by adjuvants leading to the autoimmune/inflammatory syndrome induced by adjuvants (ASIA syndrome). In conclusion, there are several case reports of autoimmune diseases following vaccines, however, due to the limited number of cases, the different classifications of symptoms and the long latency period of the diseases, every attempt for an epidemiological study has so far failed to deliver a connection. Despite this, efforts to unveil the connection between the triggering of the immune system by adjuvants and the development of autoimmune conditions should be undertaken. Vaccinomics is a field that may bring to light novel customized, personalized treatment approaches in the future.

Interferon alpha for the adjuvant treatment of cutaneous melanoma

BACKGROUND

Interferon alpha is the only agent approved for the postoperative adjuvant treatment of high-risk cutaneous melanoma. However, the survival advantage associated with this treatment is unclear, especially in terms of overall survival. Thus, adjuvant interferon is not universally considered a gold standard treatment by all oncologists.

OBJECTIVES

To assess the disease-free survival and overall survival effects of interferon alpha as adjuvant treatment for people with high-risk cutaneous melanoma.

SEARCH METHODS

We searched the following databases up to August 2012: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2012, issue 8), MEDLINE (from 2005), EMBASE (from 2010), AMED (from 1985), and LILACS (from 1982). We also searched trials databases in 2011, and proceedings of the ASCO annual meeting from 2000 to 2011. We checked the reference lists of selected articles for further references to relevant trials.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) comparing interferon alpha to observation (or any other treatment) for the postoperative (adjuvant) treatment of patients with high-risk skin melanoma, that is, people with regional lymph node metastasis (American Joint Committee on Cancer (AJCC) TNM (tumour, lymph node, metastasis) stage III) undergoing radical lymph node dissection, or people without nodal disease but with primary tumour thickness greater than 1 mm (AJCC TNM stage II).

DATA COLLECTION AND ANALYSIS

Two authors extracted data, and a third author independently verified the extracted data. The main outcome measure was the hazard ratio (HR), which is the ratio of the risk of the event occurring in the treatment arm (adjuvant interferon) compared to the control arm (no adjuvant interferon). The survival data were either entered directly into Review Manager (RevMan) or extrapolated from Kaplan-Meier plots and then entered into RevMan. Based on the presence of between-study heterogeneity, we applied a fixed-effect or random-effects model for calculating the pooled estimates of treatment efficacy.

MAIN RESULTS

Eighteen RCTs enrolling a total of 10,499 participants were eligible for the review. The results from 17 of 18 of these RCTs, published between 1995 and 2011, were suitable for meta-analysis and allowed us to quantify the therapeutic efficacy of interferon in terms of disease-free survival (17 trials) and overall survival (15 trials). Adjuvant interferon was associated with significantly improved disease-free survival (HR (hazard ratio) = 0.83; 95% CI (confidence interval) 0.78 to 0.87, P value < 0.00001) and overall survival (HR = 0.91; 95% CI 0.85 to 0.97; P value = 0.003). We detected no significant between-study heterogeneity (disease-free survival: I² statistic = 16%, Q-test P value = 0.27; overall survival: I² statistic = 6%; Q-test P value = 0.38).Considering that the 5-year overall survival rate for TNM stage II-III cutaneous melanoma is 60%, the number needed to treat (NNT) is 35 participants (95% CI = 21 to 108 participants) in order to prevent 1 death. The results of subgroup analysis failed to answer the question of whether some treatment features (i.e. dosage, duration) might have an impact on interferon efficacy or whether some participant subgroups (i.e. with or without lymph node positivity) might benefit differently from interferon adjuvant treatment.Grade 3 and 4 toxicity was observed in a minority of participants: In some trials, no-one had fever or fatigue of Grade 3 severity, but in other trials, up to 8% had fever and up to 23% had fatigue of Grade 3 severity. Less than 1% of participants had fever and fatigue of Grade 4 severity. Although it impaired quality of life, toxicity disappeared after treatment discontinuation.

AUTHORS' CONCLUSIONS

The results of this meta-analysis support the therapeutic efficacy of adjuvant interferon alpha for the treatment of people with high-risk (AJCC TNM stage II-III) cutaneous melanoma in terms of both disease-free survival and, though to a lower extent, overall survival. Interferon is also valid as a reference treatment in RCTs investigating new therapeutic agents for the adjuvant treatment of this participant population. Further investigation is required to select people who are most likely to benefit from this treatment.

Type I and II IFNs inhibit Merkel cell carcinoma via modulation of the Merkel cell polyomavirus T antigens

Merkel cell carcinoma (MCC) is a rare and highly aggressive skin cancer associated with the Merkel cell polyomavirus (MCV). As MCC cell lines show oncogene addiction to the MCV T antigens, pharmacologic interference of the large T antigen (LTA) may represent an effective therapeutic approach for this deadly cancer. In this study, we investigated the effects of IFNs on MCC cell lines, especially on MCV-positive (MCV(+)) lines. Type I IFNs (i.e., Multiferon, a mix of different IFN-α subtypes, and IFN-β) strongly inhibited the cellular viability. Cell-cycle analysis showed increased sub-G fractions for these cells upon IFN treatment indicating apoptotic cell death; these effects were less pronounced for IFN-γ. Notably, this inhibitory effect of type I IFNs on MCV(+) MCC cell lines was associated with a reduced expression of the MCV LTA as well as an increased expression of promyelocytic leukemia (PML) protein, which is known to interfere with the function of the LTA. In addition, the intratumoral application of Multiferon resulted in a regression of MCV(+) but not MCV(-) MCCs in vivo. Together, our findings show that type I IFNs have a strong antitumor effect, which is at least in part explained by modulation of the virally encoded LTA.

Prognostic significance of autoimmunity during treatment of melanoma with interferon

Since the pivotal cooperative group trials in the 1980's-90's,, high-dose interferon (HDI) has been the standard of adjuvant therapy. Despite multiple other trials evaluating potential new therapies in melanoma, HDI remains the only FDA-approved therapy for stage IIB and III melanoma. Initial reports from the more recent phase III international trials of modifications of the original HDI regimen linked the appearance of autoimmunity with improved outcomes of disease. Trials of high-dose interleukin-2, many years earlier, reported anecdotal observations that were consistent with the hypothesis that autoimmunity and clinical benefit of immunotherapies of melanoma are linked with one another. The only prospectively conducted study examining the appearance of clinical and laboratory evidence of autoimmunity during HDI therapy was published by Gogas and colleagues, demonstrating statistically significant impact on relapse-free survival and overall survival. Retrospectively conducted studies of different intermediate dosage regimens of interferon (IFN) have not fully confirmed the linkage of serological evidence of autoimmunity and improved survival outcomes. With the emergence of new immunotherapies in treatment of melanoma, this review highlights the importance of autoimmunity for future applications in melanoma and reviews significant differences of past studies evaluating the appearance of autoimmunity during IFN therapy in high-risk melanoma.

Adjuvants and autoimmunity

Some adjuvants may exert adverse effects upon injection or, on the other hand, may not trigger a full immunological reaction. The mechanisms underlying adjuvant adverse effects are under renewed scrutiny because of the enormous implications for vaccine development. In the search for new and safer adjuvants, several new adjuvants were developed by pharmaceutical companies utilizing new immunological and chemical innovations. The ability of the immune system to recognize molecules that are broadly shared by pathogens is, in part, due to the presence of special immune receptors called toll-like receptors (TLRs) that are expressed on leukocyte membranes. The very fact that TLR activation leads to adaptive immune responses to foreign entities explains why so many adjuvants used today in vaccinations are developed to mimic TLR ligands. Alongside their supportive role, adjuvants were found to inflict by themselves an illness of autoimmune nature, defined as ‘the adjuvant diseases’. The debatable question of silicone as an adjuvant and connective tissue diseases, as well as the Gulf War syndrome and macrophagic myofaciitis which followed multiple injections of aluminium-based vaccines, are presented here. Owing to the adverse effects exerted by adjuvants, there is no doubt that safer adjuvants need to be developed and incorporated into future vaccines. Other needs in light of new vaccine technologies are adjuvants suitable for use with mucosally delivered vaccines, DNA vaccines, cancer and autoimmunity vaccines. In particular, there is demand for safe and non-toxic adjuvants able to stimulate cellular (Th1) immunity. More adjuvants were approved to date besides alum for human vaccines, including MF59 in some viral vaccines, MPL, AS04, AS01B and AS02A against viral and parasitic infections, virosomes for HBV, HPV and HAV, and cholera toxin for cholera. Perhaps future adjuvants occupying other putative receptors will be employed to bypass the TLR signaling pathway completely in order to circumvent common side effects of adjuvant-activated TLRs such as local inflammation and the general malaise felt because of the costly whole-body immune response to antigen. Lupus (2009) 18, 1217—1225.