Intermediate dose recombinant interferon-alpha as second-line treatment for patients with recurrent cutaneous melanoma who were pretreated with low dose interferon

Antiviral Responses in Cancer: Boosting Antitumor Immunity Through Activation of Interferon Pathway in the Tumor Microenvironment

In recent years, it became apparent that cancers either associated with viral infections or aberrantly expressing endogenous retroviral elements (EREs) are more immunogenic, exhibiting an intense intra-tumor immune cell infiltration characterized by a robust cytolytic apparatus. On the other hand, epigenetic regulation of EREs is crucial to maintain steady-state conditions and cell homeostasis. In line with this, epigenetic disruptions within steady-state cells can lead to cancer development and trigger the release of EREs into the cytoplasmic compartment. As such, detection of viral molecules by intracellular innate immune sensors leads to the production of type I and type III interferons that act to induce an antiviral state, thus restraining viral replication. This knowledge has recently gained momentum due to the possibility of triggering intratumoral activation of interferon responses, which could be used as an adjuvant to elicit strong anti-tumor immune responses that ultimately lead to a cascade of cytokine production. Accordingly, several therapeutic approaches are currently being tested using this rationale to improve responses to cancer immunotherapies. In this review, we discuss the immune mechanisms operating in viral infections, show evidence that exogenous viruses and endogenous retroviruses in cancer may enhance tumor immunogenicity, dissect the epigenetic control of EREs, and point to interferon pathway activation in the tumor milieu as a promising molecular predictive marker and immunotherapy target. Finally, we briefly discuss current strategies to modulate these responses within tumor tissues, including the clinical use of innate immune receptor agonists and DNA demethylating agents.

The use of interferon in melanoma patients: a systematic review

Interferon (IFN) and PEG-IFN are the only drugs approved as adjuvant therapy in patients with melanoma at high-risk of recurrence after surgical resection. Several clinical trials of adjuvant IFN, using different doses and durations of therapy, have been conducted in these patients. Results generally suggest relapse-free survival and overall survival benefits; however, questions over the optimal dose and duration of treatment and concerns over toxicity have limited its use. IFN exerts its biological activity in melanoma via multiple mechanisms of action, most of which can be considered as indirect immunomodulatory effects. As such, IFN may also be of benefit in the neoadjuvant setting, where it may have a role in melanoma patients with locally advanced disease for whom immediate surgical excision is not possible. However, this has not been well studied. The use of IFN in patients with metastatic melanoma is controversial, with limited data and no convincing evidence of a survival benefit. However, IFN therapy combined with novel biological and immunotherapies offers the potential for a synergistic effect and improved clinical outcomes. Predictive and prognostic factors to better select melanoma patients for IFN treatment have been identified (e.g. disease stage, ulceration, various cytokines) and may also enhance its therapeutic efficacy, but their incorporation into the clinical decision-making process requires validation in prospective trials. In conclusion, the modest efficacy of IFN shown in clinical trials is largely a reflection of differences in response between patients. Despite advancements in the understanding of its biological mechanisms of action, the huge potential of IFN remains to be fully explored and utilized in patients with melanoma.

Pharmacokinetic and pharmacodynamic comparison of two "pegylated" interferon alpha-2 formulations in healthy male volunteers: a randomized, crossover, double-blind study

BACKGROUND

Interferon (IFN) alpha conjugation to polyethylene glycol (PEG) results in a better pharmacokinetic profile and efficacy. The aim of this study was to compare the pharmacokinetic, pharmacodynamic and safety properties of a new, locally developed, 40-kDa PEG-IFN alpha-2b preparation with a reference, commercially available PEG-IFN alpha-2a in healthy male volunteers.

METHODS

A randomized, crossover, double-blind study with a 3-weeks washout period, was done. A single 180 micrograms PEG-IFN alpha-2 dose was administered subcutaneously in both groups. Sixteen apparently healthy male subjects were included. Serum PEG-IFN concentration was measured during 336 hours by an enzyme immunoassay (EIA). Other clinical and laboratory variables were used as pharmacodynamic and safety criteria.

RESULTS

The pharmacokinetic comparison by EIA yielded a high similitude between the formulations. In spite of a high subject variability, the parameters' mean were very close (in all cases p > 0.05): AUC: 53623 vs. 44311 pg.h/mL; Cmax: 333 vs. 271 pg/mL; Tmax: 54 vs. 55 h; half-life (t1/2): 72.4 vs. 64.8 h; terminal elimination rate (lambda): 0.011 vs. 0.014 h(-1); mean residence time (MRT): 135 vs. 123 h for reference and study preparations, respectively. There were no significant differences with respect to the pharmacodynamic variables either: serum neopterin and beta-2 microglobulin levels, stimulation of 2'5' oligoadenylate synthetase expression, and serum IFN antiviral activity. A strong Spearman's rank order correlation (p < 0.01) between the pharmacokinetic and pharmacodynamic concentration-time curves was observed. Both products caused similar leukocyte counts diminution and had similar safety profiles. The most frequent adverse reactions were leukopenia, fever, thrombocytopenia, transaminases increase and asthenia, mostly mild.

CONCLUSIONS

Both formulations are fully comparable from the pharmacokinetic, pharmacodynamic, and safety profiles. Efficacy trials can be carried out to confirm clinical similarity.

Bioequivalence of two recombinant interferon alpha-2b liquid formulations in healthy male volunteers

OBJECTIVE

Interferon (IFN) alpha-2b is a protein with antiviral, antiproliferative and immunoregulatory properties that is approved for several clinical indications. A new liquid, albumin-free, IFNalpha-2b formulation has recently been developed. This study aimed to evaluate the equivalence of the pharmacokinetic, pharmacodynamic and safety properties of the new formulation with a reference one in healthy male volunteers.

METHODS

A randomised, crossover, double-blind study with a 3-week washout period was performed in which Heberon Alfa R (formulation A) and Viraferon (formulation B) were compared. A single 20 x 10(6) IU IFNalpha-2b dose was administered subcutaneously to 14 apparently healthy male subjects. Serum IFN level was measured over 48 hours by enzyme immunoassay (EIA) and by antiviral activity titration. Clinical and laboratory variables were determined, as were pharmacodynamic and safety criteria.

RESULTS

Groups were homogeneous with regard to all demographic and baseline variables. Pharmacokinetic comparison by EIA did not show differences between the formulations: area under the curve (AUC) 2572 versus 2561 ng x h/L, maximum plasma concentration (Cmax) 318 versus 354 ng/L, time to Cmax (tmax) 8.2 versus 8.5 h, elimination half-life (t(1/2)) 5.87 versus 6.08 h, terminal elimination rate (lambda) 0.122 versus 0.118 h(-1), and mean residence time (MRT) 10.9 versus 12.0 h for formulations A and B, respectively. The differences never reached 20%, which is the clinically significant threshold. The 90% confidence interval of the ratio between them was in all cases within the 0.8, 1.25 range. The two formulations were clinically equivalent with regard to serum IFN antiviral activity titration (0.8, 1.25 criterion) regarding their pharmacokinetic parameters. There were no significant differences with respect to the pharmacodynamic variables: serum beta2-microglobulin and temperature increase. Heart rate and blood pressure changes did not differ either. Both products provoked similar haematological count decreases and had similar safety profiles. The most frequent adverse reactions were fever, tachycardia, headache and arthralgias.

CONCLUSION

The overall analysis strongly suggests the bioequivalence of these two products.

Adjuvant treatment of malignant melanoma: where are we?

To date, no standard adjuvant therapy have increased overall survival in patients with malignant melanoma (MM). The effect of interferon alpha as a single agent or in combination has been widely explored in clinical trials. Critical reading of the major international randomised trials showed that response to interferon (IFN) in terms of improvement of overall survival (OS) may not be strictly correlated with the used dosage and that duration of therapy may impact disease-free survival (DFS) but not OS. Patients' heterogeneity could be an explanation for the discordant data of the international literature. Indeed, majority of these studies started in late 1980s or early 1990s, when accurate staging procedure were not available yet. The adequate surgical treatment should be considered as an independent variable in the analysis of MM adjuvant protocols. Considering the treatment cost, which is the main goal: DFS, OS or quality of life? Answering these questions is difficult, but some considerations must be taken to put order in this field. Putting together data from all different studies, IFN therapy seems to protect MM patients from recurrences during the entire treatment period and a prolonged IFN therapy seems to improve DFS. The only positive result on OS was demonstrated for high-dose IFN (HD-IFN) in a single study (presenting a relatively short follow-up median) and not confirmed in a subsequent study from the same authors. Considering that low-dose interferon (LD-IFN) is tolerated much better than HD-IFN (about 10% versus more than 70% of cases with grade 3-4 toxicity, respectively), a prolonged LD-IFN (more than 2 years) may represent a reasonable opportunity for MM patients, also considering its advantageous cost-effectiveness. Conversely, considering the improvement of OS as the main target of MM adjuvant therapy, the "wait and watch" attitude remains the only approach to be pursued at present. It is a physician's choice.