Phase I trial of 40-kd branched pegylated interferon alfa-2a for patients with advanced renal cell carcinoma

Real-world study of pegylated interferon α-2a to treat mycosis fungoides/Sézary syndrome using time to next treatment as a measure of clinical benefit: an EORTC CLTG study

BACKGROUND

Mycosis fungoides (MF) and Sézary syndrome (SS) are chronic malignant diseases that typically necessitate diverse strategies to achieve remission. Systemic interferon (IFN)-α (subtypes 2a and 2b) has been used to treat MF/SS since 1984; however, its production was recently stopped. The recombinant pegylated (PEG) form of IFN-α-2a remains the only alternative IFN treatment, although it has not been approved for use in MF/SS.

OBJECTIVES

To assess the effectiveness and safety of PEG-IFN-α-2a in monotherapy and in combination with other treatments using time to next treatment (TTNT) as a measure of clinical therapeutic benefit in a real-world setting.

METHODS

We conducted an international, multicentre retrospective study of patients with MF and SS (of any stage) treated with PEG-IFN-α-2a from July 2012 to February 2022. Patients were included across 11 centres in 10 countries. The primary endpoints were to determine the TTNT of PEG-IFN-α-2a and adverse events (AEs) in MF/SS.

RESULTS

In total, 105 patients were included [mean (SD) age 61 (13.1) years]; 42 (40.0%) had stage IA-IIA and 63 (60.0%) had stage IIB-IVB disease. PEG-IFN-α-2a was combined with other therapies in 67 (63.8%) patients, most commonly with extracorporeal photopheresis (36%) and bexarotene (22%). Patients with stage I-IIA disease achieved an overall response rate (ORR) of 57%; the ORR in those with stage IIB-IVB disease was 51%. Combination treatment resulted in a median TTNT of 10.4 months (range 0.6-50.7) vs. 7.0 months (range 0.7-52.4) for those who received monotherapy (P < 0.01). Overall, the mean (SD) TTNT was 9.2 (10.6) months and the ORR was 53.3% (n = 56). A complete response was seen in 13% of patients and a partial response in 40%. AEs were described in 68.6% (n = 72) of patients. Flu-like symptoms (n = 28; 26.7%), lymphopenia (n = 24; 22.9%) and elevated liver function (n = 10; 9.5%) were the most frequently reported. Grade 3-4 AEs were reported in 23 (21.9%) patients, mostly related to myelosuppression.

CONCLUSIONS

PEG-IFN-α-2a for MF/SS resulted in an ORR of 53.3% and a mean (SD) TTNT of 9.2 (10.6) months. Combination regimens were superior to monotherapy and doses of 180 µg PEG-IFN-α-2a weekly were related to a higher ORR.

HeberFERON, a new formulation of IFNs with improved pharmacodynamics: Perspective for cancer treatment

The rational combination of recombinant IFN-α2b and IFN-γ resulted in a new formulation of interferons (HeberFERON) with improved pharmacodynamics. In basal cell carcinomas HeberFERON produces a more rapid antitumor effect and results in a larger number of complete responses. In patients with glioblastoma multiforme, the administration of HeberFERON after surgery and radiotherapy results in an estimated overall survival of 19 months. Patients with stage III or IV renal cell carcinoma also appear to benefit from the intravenous administration of HeberFERON, with prolongation of survival and good quality of live. HeberFERON offers a promising alternative formulation of interferons for the treatment of cancer with a very favorable safety profile.

Dose-escalation study evaluating pegylated interferon alpha-2a in patients with cutaneous T-cell lymphoma

BACKGROUND

This open-label, multicenter, dose-escalation study evaluated the safety, tolerability, and efficacy of subcutaneous pegylated (40 kD) interferon α-2a (PEG-IFN α-2a) in patients with cutaneous T-cell lymphoma (CTCL).

PATIENTS AND METHODS

PEG-IFN α-2a was administered subcutaneously at 180 (n = 4), 270 (n = 6), or 360 μg (n = 3) once weekly for 12 weeks. Efficacy was assessed by the proportion of patients with complete response (CR) or partial response (PR).

RESULTS

PEG-IFN α-2a was generally well tolerated, with a moderate number of reductions or withholding of doses because of adverse events (AEs) (25% (n = 1), 66% (n = 4), and 0% (n = 0) in the 180-, 270-, and 360-μg/week groups, respectively). The only dose-limiting toxicity was a grade 3 elevation of liver enzymes in the 270-μg dose group. The most common AEs were fatigue, acute flu-like symptoms, and hepatic toxicity. The major response rate (CR or PR) was 50% in the 180-μg group (CR, 50%; PR, 0%), 83% in the 270-μg group (CR, 67%; PR, 17%), and 66% in the 360-μg group (CR, 33%; PR, 33%).

CONCLUSION

PEG-IFN α-2a at doses up to 360 μg once weekly was well tolerated in patients with CTCL up to the highest dose group and showed good response rates. Due to their good tolerance even in high doses, they might be an option for patients not tolerating standard IFN-α preparations. However, for this purpose and to evaluate comparability between standard and PEG-IFN larger clinical trials are needed, alone and in combination with oral photochemotherapy (PUVA).

Pharmacokinetic and pharmacodynamic characterization of a novel formulation containing co-formulated interferons alpha-2b and gamma in healthy male volunteers

Background

More potent antitumor activity is desired in Interferon (IFN)-treated cancer patients. This could be achieved by combining IFN alpha and IFN gamma. The aim of this work was to characterize the pharmacokinetics and pharmacodynamics of a novel formulation containing a co-formulated combination of IFNs alpha-2b and gamma (CIGB-128-A).

Methods

A group of nine healthy male subjects received intramuscularly 24.5 × 10⁶ IU of CIGB-128-A. IFN concentrations were evaluated for 48 h. Serum neopterin, beta2-microglobulin (β₂M) and 2′–5′ oligoadenylate synthetase (2′–5′ OAS), classical IFN-inducible serum markers, were measured during 192 h by enzyme immunoassay and body temperature was used as pharmacodynamic variable as well.

Results

Concerning pharmacokinetics, serum IFNs’ profiles were better fitted to a mono-compartmental model with consecutive zero order and first order absorption, one bioavailability value. No interferences by simultaneous administered IFNs were observed in their typical similar systemic profiles. Neopterin and β₂M time profiles showed a delay that was efficiently linked to pharmacokinetics by means of a zero order absorption rate constant. Neopterin level was nine-fold higher than initial values, 48 h post-administration, an increment not described before. At this time, mean serum β₂M peaked around the double from baseline. Serum concentrations of the enzyme 2′–5′ OAS was still elevated on the 8 day post-injection. The formulation was well tolerated. Most frequent adverse reactions were fever, headache, arthralgia and lymphopenia, mostly mild.

Conclusions

The administration of co-formulated IFN alpha-2b and IFN gamma likely provides improved pharmacodynamic properties that may be beneficial to treat several malignancies.

Trial registration

Cuban Public Registry of Clinical Trials RPCEC00000118, May 24, 2011.

A pharmacokinetic and pharmacodynamic comparison of a novel pegylated recombinant consensus interferon-α variant with peginterferon-α-2a in healthy subjects

AIMS

The aims of the study were to assess the pharmacokinetics, pharmacodynamics, safety and tolerability of a novel, pegylated recombinant human consensus interferon-α variant (PEG-IFN-SA) in healthy volunteers. A pharmacokinetic and pharmacodynamic comparison of PEG-IFN-SA and peginterferon-α-2a in healthy subjects was evaluated.

METHODS

A randomized, dose-escalating, single administration dose phase I clinical study was conducted. Thirty healthy subjects received PEG-IFN-SA as a single dose of 0.5-2.0 μg kg(-1) by subcutaneous (s.c.) injection in four parallel groups. Eight subjects received peginterferon-α-2a as a single dose of 180 μg s.c.

RESULTS

The incidence rates of adverse events for PEG-IFN-SA and peginterferon-α-2a were 29 of 30 and 7 of 8, respectively. The adverse events for PEG-IFN-SA were mild to moderate and similar to those of peginterferon-α-2a. Within 168 h after injection, the mean values of maximal concentration and area under the plasma concentration-time curve from time of dosing to 168 h [AUC(0-168h) ] for 2',5'-oligoadenylate, neopterin and β2 -microglobulin for PEG-IFN-SA at 1.5 μg kg(-1 ) s.c. were similar to or higher than those for peginterferon-α-2a at a dose of 180 μg s.c. After s.c. injection of PEG-IFN-SA at 1.5 μg kg(-1) , the mean geometric mean values of plasma half-life, time to maximal concentration, maximal concentration and AUC(0-168h) were 55.3 h, 26.9 h, 0.53 μg l(-1) and 44.0 μg l(-1)  h, respectively.

CONCLUSIONS

The tolerance, pharmacokinetic and pharmacodynamic characteristics of PEG-IFN-SA support its administration by s.c. injection as a single dose of 1.5 μg kg(-1) or at 2.0 μg kg(-1) per week.

Pegylated interferon pharmacokinetics and self-reported depressive symptoms during antiviral treatment for chronic hepatitis C

BACKGROUND

Pegylated interferon-2a (PegIFN-2a)+ribavirin treatment for chronic hepatitis C is often associated with depressive symptoms. Previous studies have failed to explore whether PegIFN-2a pharmacokinetic variability plays an etiologic role in PegIFN-2a-induced mood disorders. The objective of this investigation was to evaluate the association between trough PegIFN-2a concentration at treatment week 4 ("PegIFN-2a Cmin4") and an increase in depressive symptoms.

METHODS

Using data from Virahep-C, the association between PegIFN-2a Cmin4 and the following depression outcomes were evaluated using the Center for Epidemiological Studies-Depression scale (CES-D): (1) change in CES-D score from baseline to week 12; (2) greatest difference in CES-D score between baseline and weeks 4, 12, or 24; and (3) occurrence of severe depressive symptoms (CES-D greater than 23) at weeks 4, 12, or 24. One post-hoc analysis examined whether PegIFN-2a exposure during the first week of treatment was associated with change in CES-D score from baseline to week 4.

RESULTS

No significant associations between PegIFN-2a Cmin4 and the depression outcomes were observed (p>0.05). Exploratory analyses suggest a possible relationship between PegIFN-2a exposure during the first week of therapy and CES-D score change from baseline to week 4 (p=0.03).

CONCLUSIONS

PegIFN-2a concentration levels from baseline to week 4 do not predict the onset and severity of depressive symptoms during 24 weeks of antiviral therapy; however PegIFN-2a levels during the first week of treatment may predict depressive symptoms in the first 4 weeks, earlier than anticipated and warrants further exploration.

Saturable human neopterin response to interferon-α assessed by a pharmacokinetic-pharmacodynamic model

BACKGROUND

In this study, we developed a pharmacokinetic (PK)- pharmacodynamic (PD) model of a new sustained release formulation of interferon-α-2a (SR-IFN-α) using the blood concentration of IFN-α and neopterin in order to quantify the magnitude and saturation of neopterin production over time in healthy volunteers. The SR-IFN-α in this study is a solid microparticular formulation manufactured by spray drying of a feeding solution containing IFN-α, a biocompatible polymer (polyethylene glycol) and sodium hyaluronate.

METHODS

The full PK and PD (neopterin concentration) datasets from 24 healthy subjects obtained after single doses of 9, 18, 27 and 36 MIU of subcutaneous SR-IFN-α were used to build the mixed-effect model using NONMEM (version 7.2) with the GFORTRAN compiler.

RESULTS

A one-compartment model with first-order elimination and a mixture of zero- and first-order absorption was chosen to describe the PK of SR-IFN-α. The time-concentration profile of neopterin, the PD marker, was described by a turnover model combined with a single transit compartment. The saturable pattern of the neopterin response blurring the dose-response relationship of SR-IFN-α was addressed by introducing the concept of the EC50 increasing over time.

CONCLUSIONS

The PK-PD model of SR-IFN-α developed in this study has presented a quantitative tool to assess the time-course of a saturable neopterin response in humans.

Targeting both IGF-1R and mTOR synergistically inhibits growth of renal cell carcinoma in vitro

BACKGROUND

Advanced or metastatic renal cell carcinoma (RCC) has a poor prognosis, because it is relatively resistant to conventional chemotherapy or radiotherapy. Treatments with human interferon-α2b alone or in combination with mammalian target of rapamycin (mTOR) inhibitors have led to only a modest improvement in clinical outcome. One observation made with mTOR inhibitors is that carcinomas can overcome these inhibitory effects by activating the insulin-like growth factor-I (IGF-I) signaling pathway. Clinically, there is an association of IGF-I receptor (IGF-IR) expression in RCC and poor long-term patient survival. We have developed a humanized anti-IGF-IR monoclonal antibody, hR1, which binds to RCC, resulting in effective down-regulation of IGF-IR and moderate inhibition of cell proliferation in vitro. In this work, we evaluate the anti-tumor activity of two novel IGF-1R-targeting agents against renal cell carcinoma given alone or in combination with an mTOR inhibitor.

METHODS

hR1 was linked by the DOCK-AND-LOCK™ (DNL™) method to four Fabs of hR1, generating Hex-hR1, or to four molecules of interferon-α2b, generating 1R-2b. Eight human RCC cell lines were screened for IGF-1R expression and sensitivity to treatment with hR1 in vitro. Synergy with an mTOR inhibitor, temsirolimus, was tested in a cell line (ACHN) with low sensitivity to hR1.

RESULTS

Hex-hR1 induced the down-regulation of IGF-IR at 10-fold lower concentrations compared to the parental hR1. Sensitivity to growth inhibition mediated by hR1 and Hex-hR1 treatments correlated with IGF-1R expression (higher expression was more sensitive). The potency of 1R-2b to inhibit the in vitro growth of RCC was also demonstrated in two human cell lines, ACHN and 786-O, with EC50-values of 63 and 48 pM, respectively. When combined with temsirolimus, a synergistic growth-inhibition with hR1, Hex-hR1, and 1R-2b was observed in ACHN cells at concentrations as low as 10 nM for hR1, 1 nM for Hex-hR1, and 2.6 nM for 1R-2b.

CONCLUSIONS

Both Hex-hR1 and 1R-2b proved to be more potent than parental hR1 in inhibiting growth of RCC in vitro. Synergy was achieved when each of the three hR1-based agents was combined with temsirolimus, suggesting a new approach for treating RCC.

Novel interferon-based pre-transplantation conditioning in the treatment of a congenital metabolic disorder

Hematopoietic stem cell (HSC) gene therapy is a potentially curative treatment modality for monogenic hematological diseases and storage disorders. It is necessary, however, to establish pre-bone marrow (BM) transplant conditioning regimens that minimize DNA damage and toxicity. Type I interferon (IFN) signaling activates quiescent HSCs and enables them to be sensitive to 5-fluorouracil (FU)-mediated cytotoxicity, thus implying a molecular basis for improving HSC transplant outcomes. Here we show that type I IFN preconditioning, without irradiation or DNA alkylating agents, significantly enhanced the HSC engraftment efficiency in wild-type (WT) recipient mice. The importance of active type I IFN signaling in HSC recipients was further demonstrated using mice lacking IFN regulatory factor 2 (IRF2), a transcriptional suppressor of type I IFN signaling. In both WT and Irf2(-/-) recipients, active type I IFN signaling greatly enhanced the sensitivity to 5-FU or low-dose irradiation of HSCs. Importantly, IFN-based pre-BM transplant conditioning was also applicable to the treatment of Sly syndrome, a congenital storage disorder with β-glucuronidase deficiency, in which it restored enzyme expression at the HSC level and reciprocally reduced pathological glycosaminoglycan storage. Our findings suggest type I IFN-based preconditioning, combined with HSC transplantation, as a novel nongenotoxic treatment of some congenital diseases.

Antiviral activity of the interferon α family: biological and pharmacological aspects of the treatment of chronic hepatitis C

INTRODUCTION

Type I interferons (IFNs) comprise a group of at least 13 structurally related subtypes of IFN-α with similar, but not identical, biological activities. Each subtype displays a unique activity profile; only IFN-α2a and IFN-α2b subtypes together with natural IFN-α preparations are currently used in the clinical practice, so that the remaining IFN-α subtypes are a still unexploited reservoir of opportunity also in the new era of direct-acting antiviral agents for the treatment of hepatitis C virus (HCV).

AREAS COVERED

This paper reviews recent progress in the study of the biology of IFN family, the antiviral action mechanism and the strategies employed by HCV to evade IFN action. Currently available IFN preparations for the treatment of chronic hepatitis C infection are described and what is currently known on the pharmacokinetics, pharmacodynamics and immunogenicity of IFN-α preparations used in clinical practice are summarized.

EXPERT OPINION

The characterization of multifunctional nature of IFN system together with recent advances in the identification of HCV IFN evasion strategies and the variety of host factors influencing IFN treatment response should be considered to improve HCV and other infectious diseases treatment in the future.

Pharmacokinetic and pharmacodynamic characterization of a new formulation containing synergistic proportions of interferons alpha-2b and gamma (HeberPAG) in patients with mycosis fungoides: an open-label trial

Background

The synergistic combination of interferon (IFN) alpha-2b and IFN gamma results in more potent in vitro biological effects mediated by both IFNs. The aim of this investigation was to evaluate by first time the pharmacokinetics and pharmacodynamics of this combination in patients with mycosis fungoides.

Methods

An exploratory, prospective, open-label clinical trial was conducted. Twelve patients, both genders, 18 to 75 years-old, with mycosis fungoides at stages IB to III, were eligible for the study. All of them received intramuscularly a single high dose (23 × 10⁶ IU) of a novel synergistic IFN mixture (HeberPAG®) for pharmacokinetic and pharmacodynamic studies. Serum IFN alpha-2b and IFN gamma concentrations were measured during 96 hours by commercial enzyme immunoassays (EIA) specific for each IFN. Other blood IFN-inducible markers and laboratory variables were used as pharmacodynamics and safety criteria.

Results

The pharmacokinetic evaluation by EIA yielded a similar pattern for both IFNs that are also in agreement with the well-known described profiles for these molecules when these are administered separately. The average values for main parameters were: Cmax: 263 and 9.3 pg/mL; Tmax: 9.5 and 6.9 h; AUC: 4483 and 87.5 pg.h/mL, half-life (t_1/2): 4.9 and 13.4 h; mean residence time (MRT): 13.9 and 13.5 h, for serum IFN alpha-2b and IFN gamma, respectively. The pharmacodynamic variables were strongly stimulated by simultaneous administration of both IFNs: serum neopterin and beta-2 microglobulin levels (β₂M), and stimulation of 2’-5’ oligoadenylate synthetase (OAS1) mRNA expression. The most encouraging data was the high increment of serum neopterin, 8.0 ng/mL at 48 h, not been described before for any unmodified or pegylated IFN. Additionally, β₂M concentration doubled the pre-dose value at 24–48 hours. For both variables the values remained clearly upper baseline levels at 96 hours.

Conclusions

HeberPAG®possesses improved pharmacodynamic properties that may be very useful in the oncologic setting. Efficacy trials can be carried out to confirm these findings.

Trial registration

Registro Público Cubano de Ensayos Clínicos RPCEC00000130

Use of modelling and simulation techniques to support decision making on the progression of PF-04878691, a TLR7 agonist being developed for hepatitis C

AIM

To use non-linear mixed effects modelling and simulation techniques to predict whether PF-04878691, a toll-like receptor 7 (TLR7) agonist, would produce sufficient antiviral efficacy while maintaining an acceptable side effect profile in a 'proof of concept' (POC) study in chronic hepatitis C (HCV) patients.

METHODS

A population pharmacokinetic-pharmacodynamic (PKPD) model was developed using available 'proof of pharmacology' (POP) clinical data to describe PF-04878691 pharmacokinetics (PK) and its relationship to 2',5'-oligoadenylate synthetase (OAS; marker of pharmacology) and lymphocyte levels (marker of safety) following multiple doses in healthy subjects. A second model was developed to describe the relationship between change from baseline OAS expressed as fold change and HCV viral RNA concentrations using clinical data available in HCV patients for a separate compound, CPG-10101 (ACTILON™), a TLR9 agonist. Using these models the antiviral efficacy and safety profiles of PF-04878691 were predicted in HCV patients.

RESULTS

The population PKPD models described well the clinical data as assessed by visual inspection of diagnostic plots, visual predictive checks and precision of the parameter estimates. Using these relationships, PF-04878691 exposure and HCV viral RNA concentration was simulated in HCV patients receiving twice weekly administration for 4 weeks over a range of doses. The simulations indicated that significant reductions in HCV viral RNA concentrations would be expected at doses > 6 mg. However at these doses grade ≥ 3 lymphopenia was also predicted.

CONCLUSIONS

The model simulations indicate that PF-04878691 is unlikely to achieve POC criteria and support the discontinuation of this compound for the treatment of HCV.

Biotherapeutic bioanalysis: a multi-indication case study review

A thorough understanding of the structure and biology of a biotherapeutic is crucial to defining a suitable strategy for pharmacokinetic characterization in proof-of-concept disease models, toxicology species as well as the healthy and disease indication patient populations. This manuscript summarizes parameters that impact bioanalytical strategy for over 50 biotherapeutics indicated for the treatment of oncology, rheumatoid arthritis, allergy, multiple sclerosis, hematology, metabolism and infectious disease. We have addressed numerous therapeutic modalities including chimeric, humanized and fully human monoclonal antibodies, replacement proteins, peptides and fusion proteins, including polyethylene glycol and Fc fusions, as well as antibody–drug conjugates. With the rapid evolution of biotherapeutics over the last 20 years and the contraction of the pharmaceutical and biotechnology labor force, efficient workflow management becomes a crucial bioanalytical component. Thus, we have also addressed new technologies that have demonstrated either increased throughput or enhanced characterization, including Meso Scale Discovery, Gyrolab and affinity MS.

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.

Quantitative determination of pegylated consensus interferon in rhesus monkey serum using a competitive enzyme-linked immunosorbent assay

A competitive enzyme-linked immunosorbent assay (ELISA) with generated mouse anti-consensus interferon (CIFN) antibody was developed for quantitative determination of pegylated consensus interferon (PEG-CIFN) in rhesus monkey serum. The operational concentrations of the original assay were determined using the chessboard method. ELISA working range was 10-5000 ng/ml, corresponding to a limit of quantification of 8.4 ng/ml in rhesus monkey serum. In a precision test, intra-assay CV ranged 1.8-9.6% and inter-assay CV ranged 3.5-12.7%. Relative recovery rate of this ELISA assay ranged from 102.65-115.77%, with RSD values ranging from 2.26-5.44%. Three groups of rhesus monkeys received 1250 microg/kg, 300 microg/kg, 150 microg/kg PEG-CIFN by subcutaneous administration, and blood samples were drawn via the femoral vein at the specified time points. PEG-CIFN in rhesus monkey serum was determined using the competitive ELISA, and the results were compared with antiviral activity assay. In conclusion, the competitive ELISA assay we developed has sufficient sensitivity, precision, and accuracy for the analysis of a rhesus monkey serum sample.

Metastatic renal cell carcinoma treated with Peg-interferon alfa-2b

INTRODUCTION

Peginterferon has an increased plasma half-life and enables a constant exposure to interferon. This modification might increase the antiangiogenic effect of the treatment and influence the efficacy. We report the results of a phase II open-label study with Peginterferon alfa-2b (Pegintron Schering-Plough) on efficacy and tolerability in patients with advanced renal cell carcinoma (MRCC).

MATERIALS AND METHODS

Twenty eight patients with MRCC were treated with Peginterferon in escalating doses of 0.5 microg/kg once weekly until 2 microg/kg was reached or prohibited toxicity occurred. Lesions were evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Thirteen patients tolerated a dose of 2 microg/kg/week. At 6 months 16 patients (57%) had disease control of which four had partial response (PR) and 12 stable disease whereas 12 (43%) had progressed. PR was only seen in the lung parenchyma or mediastinum. Median time to progression (TTP) was 8 months in all patients and 13 months for PR and SD patients. Correspondingly, median survival was 19.5 months and 28 months, respectively (seven patients received second-line treatment with tyrosine kinase inhibitor). The mean dose during long-term treatment was 1.5 and at the end of treatment 1.2 microg/kg/week. Most side effects were grade 1-2 and only two patients stopped treatment for that reason. VEGF levels in serum before and during treatment did not correlate to the therapeutic response.

DISCUSSION

Peginterferon was well tolerated in MRCC albeit with dose modification during long-term treatment. Response pattern seems to be the same as with nonpegylated interferon. Peginterferon may be used as monotherapy in selected patients and in trials of combinations with targeted drugs.

Phase II, randomized, multicenter, comparative study of peginterferon–α–2a (40 kD) (Pegasys®)versusinterferon α-2a (Roferon®-A) in patients with treatment-naïve, chronic-phase chronic myelogenous leukemia

The efficacy and safety of peginterferon-alpha-2a (40 kD) (PEG-IFNalpha-2a), 450 microg once weekly, versus IFNalpha-2a, 9 MIU once daily, for 12 months, was evaluated in a Phase II study in IFN-naïve patients with chronic-phase, Philadelphia-chromosome-positive CML. At the end of the treatment, complete hematological response was observed in 66.2% (47/71) and 45.2% (33/73) of the PEG-IFNalpha-2a group and IFNalpha-2a groups, respectively (p = 0.009), and major cytogenetic response occurred in 35.2% and 17.8%, respectively (p = 0.016). PEG-IFNalpha-2a was at least as effective as IFNalpha-2a overall, including progression-free survival at the end of treatment, and overall survival after 30 months of follow-up. Adverse events necessitated fewer withdrawals but more dose adjustments in the PEG-IFNalpha-2a group compared with the IFNalpha-2a group (11%versus 23%, and 84.5%versus 65.8%, respectively). In conclusion, PEG-IFNalpha-2a (40 kD), 450 microg once weekly, compared with IFNalpha-2a, 9 MIU once daily, resulted in higher rates of hematologic and cytogenetic response and greater overall survival.

Combined treatment with pegylated interferon-alpha-2a and dacarbazine in patients with advanced metastatic melanoma: a phase 2 study

BACKGROUND

Dacarbazine (DTIC) and pegylated interferon (IFN)-alpha-2a have both demonstrated some efficacy as single agents in metastatic melanoma. To the authors' knowledge, the current study is the first to test a combination of these 2 agents in a phase 2 trial.

METHODS

Twenty-eight patients with stage IV melanoma without brain metastases were treated with DTIC (at a dose of 850 mg/m(2) every 3 weeks) combined with weekly pegylated IFN-alpha-2a at a dose of 180 microg. The study was initiated to evaluate the efficacy and tolerability of the combination. The primary study endpoint was objective response.

RESULTS

Twenty-five patients were evaluable for response. Two patients (8.0%) achieved a complete response that continued for >480 days and 746 days, respectively. Four patients (16.0%) demonstrated a partial response, and another patient experienced stable disease. Six of 7 nonprogressive patients had either not received treatment or had not developed disease progression during adjuvant IFN treatment for stage II/III disease. The median duration of response was 236 days, the median progression-free survival was 56 days, and the overall survival time was 403 days. Few grade 3 toxicities and only 1 grade 4 toxicity were observed (according to National Cancer Institute Common Toxicity Criteria).

CONCLUSIONS

The combination of DTIC and pegylated IFN-alpha-2a was found to be well tolerated in patients with metastatic melanoma. The response rate of 24%, including 2 long-lasting complete responses, is encouraging, but must be confirmed in larger trials.

Novel Delivery Systems for Interferons

Interferons, IFNs, are among the most widely studied and clinically used biopharmaceuticals. Despite their invaluable therapeutic roles, the widespread use of IFNs suffers from some inherent limitations, mainly their relatively short circulation lifespan and their unwanted effects on some non-target tissues. Therefore, both these constraints have become the central focus points for the research efforts on the development of a variety of novel delivery systems for these therapeutic agents with the ultimate goal of improving their therapeutic end-points. Generally, the delivery systems currently under investigation for IFNs can be classified as particulate delivery systems, including micro- and nano-particles, liposomes, minipellets, cellular carriers, and non-particulate delivery systems, including PEGylated IFNs, other chemically conjugated IFNs, immunoconjugated IFNs, and genetically conjugated IFNs. All these strategies and techniques have their own possibilities and limitations, which should be taken into account when considering their clinical application. In this article, currently studied delivery systems/techniques for IFN delivery have been reviewed extensively, with the main focus on the pharmacokinetic consequences of each procedure.

Phase I trial of PEG-interferon and recombinant IL-2 in patients with metastatic renal cell carcinoma

PURPOSE

Pegylated interferon alpha-2b (PEG-Intron) is a conjugate of polyethylene glycol (PEG) and interferon alpha-2b, has a prolonged half-life, and an increased area under the curve (AUC) for interferon alpha-2b. The combination of PEG-Intron with recombinant interleukin-2 (rIL-2) was investigated in a phase 1 trial. To determine the maximal tolerable dose (MTD) and preliminary efficacy of concurrent subcutaneous (SC) administration of PEG-Intron and rIL-2 in patients with metastatic renal cell carcinoma (RCC).

METHODS

Cohorts of 3-6 patients received escalating doses of PEG-Intron (I-1.5, II- 1.5, III-3.0, IV-3.0, V-4.5 microg/kg SC) given weekly in combination with rIL-2 administered three times weekly (TIW) for 6 weeks. rIL-2 dose levels were escalated in weeks 1 and 4 (I-10.0, II-15.0, III-15.0, IV-20.0, V-20.0 MIU/m(2) SC), and 5.0 MIU/m(2) SC TIW was administered during weeks 2, 3, 5 and 6.

RESULTS

Thirty-four patients (24 men; 10 women) were accrued at dose levels I (n = 4), II (n = 4), III (n = 6), IV (n = 14), and V (n = 6) between October 2000 and October 2002. All but one patient had prior nephrectomy (n = 33) and all but one patient (97%) had received no prior systemic therapy. Patients received a median of four cycles of treatment (range 1-9). Dose limiting toxicity occurred at dose level V and included grade 4 neutropenia and hypoxemia. A partial response was found in 5 pts (15%). Median progression-free and overall survival were 9.0 (95% C.I. 5.6-13.1 months) and 31.9 months (95% C.I. 17.2-61.9 months), respectively.

CONCLUSION

The combination of PEG-Interferon and SC rIL-2 can be administered with acceptable toxicity.

Multicenter Phase II Study of Chemo-immunotherapy in the Treatment of Metastatic Renal Cell Carcinoma

The purpose of this study was to evaluate the potential efficacy of a chemo-immunotherapy regimen for the treatment of metastatic renal cell carcinoma (MRCC). Forty-one patients with progressing MRCC and with a median age of 63 years were recruited. Planned treatment consisted of 6 courses of capecitabine 1000 mg/m twice daily on days 1 to 14 every 4 weeks, pegylated alpha-interferon 2b 50 microg every week, interleukin-2 1.8 M IU subcutaneously, and oral 13-cis-retinoic acid 0.5 mg/kg, all given 5 days/wk, 3 weeks of each month. After 6 courses of concomitant biochemotherapy, biotherapy was continued in patients who had a clinical benefit. The primary end point was response; secondary end points were the evaluation of the immunologic parameters, toxicity, progression-free, and overall survival. The treatment was well-tolerated. Grade 3 and 4 neutropenia and thrombocytopenia occurred in 5% and 7% of patients, respectively. The overall response rate in the 41 evaluable patients was 53.6% (95% confidence interval 37%-69%). Median progression-free and overall survivals were 14.7 and 27.8 months, respectively. A sustained improvement in all evaluated immunologic parameters was observed in the 36 patients treated with maintenance biotherapy. Six cycles of biochemotherapy, being followed by maintenance immunotherapy is well-tolerated and shows significant activity in patients with MRCC.

Interferon-α Resistance Associated Genes in Renal Cell Carcinoma Identified by Expression Profiling

PURPOSE

We identified differentially expressed genes associated with response to pegylated interferon-alpha treatment in patients with renal cell carcinoma.

MATERIALS AND METHODS

We performed expression profiling on renal cell carcinoma specimens isolated from 23 patients with metastatic disease who were subsequently treated with interferon. Significance Analysis for Microarrays software was used to identify genes that were differentially expressed between patients with partial response compared to those with disease progression.

RESULTS

A candidate gene approach looking at VHL and known target genes did not identify any genes whose expression correlated with patient response. A global analysis of approximately 54,000 probe sets identified 4 genes that had expression correlated with response. Reverse transcriptase-polymerase chain reaction analysis of 2 of these genes confirmed that they were more highly expressed in tumors from patients who responded to interferon-alpha. Interestingly, both of these genes mapped to 4q31-32, a region that has been implicated as the site of a potential tumor suppressor gene in renal cell carcinoma.

CONCLUSIONS

We have identified 4 genes (3 uncharacterized and 1 known) that may prove useful in predicting response to interferon-alpha treatment in patients with renal cell carcinoma.

Role of Cytokine Therapy in 2006 and Beyond for Metastatic Renal Cell Cancer

Metastatic renal cell cancer (mRCC) has a long history as a disease with poor prognosis and limited therapeutic options. Immunotherapy has been the mainstay of treatment since the 1980s, and there have been a number of largely phase II studies examining various schedules of interferon-alpha and interleukin-2 based treatments. With the development of molecular targeted drugs the armentarium against mRCC has significantly expanded and cytokine treatments should be only directed at those most likely to benefit with durable remissions and prolonged survival.

Randomized dose-escalation study evaluating peginterferon alfa-2a in patients with metastatic malignant melanoma

PURPOSE

A pegylated interferon, peginterferon alfa-2a (PEG-IFNalpha-2a; 40 kd), has the potential for improved tumor response and survival with lower toxicity than IFNalpha. This open-label, randomized study evaluated the safety, tolerability, and efficacy of subcutaneous PEG-IFNalpha-2a in patients with metastatic malignant melanoma (stage IV American Joint Committee on Cancer staging system).

PATIENTS AND METHODS

PEG-IFNalpha-2a was administered subcutaneously at 180 (n = 48), 360 (n = 53), or 450 mug (n = 49) once weekly for 24 weeks, with maintenance therapy for responders. Efficacy was assessed by the proportion of patients with complete response (CR) or partial response (PR).

RESULTS

The major response rate (CR or PR) was 6% in the 180-mug group (CR, 2%; PR, 4%), 8% in the 360-mug group (CR, 2%; PR, 6%), and 12% in the 450-mug group (CR, 6%; PR, 6%). The times to achieve a major response, duration of major response, rate of disease progression, and 12-month survival were similar between groups, although overall median survival was significantly different among the three groups (P = .0136). More patients required dose adjustment for safety reasons in the higher dose groups, but PEG-IFNalpha-2a was generally well tolerated, with few withdrawals because of adverse events (6%, 19%, and 16% in the 180-, 360-, and 450-mug groups, respectively). The most common adverse events were fatigue, pyrexia, and nausea.

CONCLUSION

PEG-IFNalpha-2a at doses up to 450 mug once weekly has shown good tolerability and similar efficacy to conventional IFNalpha and monochemotherapy in stage IV metastatic melanoma.

Phase I Evaluation of a 40-kDa Branched-Chain Long-Acting Pegylated IFN-α-2a With and Without Cytarabine in Patients with Chronic Myelogenous Leukemia

PURPOSE

Pegasys (PEG-IFN) is a modified form of recombinant human IFN-alpha-2a in which IFN-alpha is attached to a branched methoxypolyethylene glycol (PEG) moiety of large molecular weight (40 kDa). Such molecular modification results in sustained absorption after s.c. drug administration and a prolonged half-life. A phase I study of PEG-IFN was conducted in patients with chronic myelogenous leukemia (CML) who were previously treated with IFN-alpha to evaluate the effect of sustained exposure to IFN on patients with CML.

EXPERIMENTAL DESIGN

Twenty-seven patients with long-term or IFN-refractory CML were enrolled in cohorts of three or six patients. PEG-IFN was given once weekly by s.c. injections starting at a dose of 270 microg/wk to a maximum dose of 630 microg/wk. Sixteen additional patients were treated with escalating doses of PEG-IFN ranging from 450 to 540 microg/wk in combination with two different schedules of low-dose cytarabine (1-beta-D-arabinofuranosylcytosine, ara-C). Serial venous blood samples were collected to evaluate the pharmacokinetic and pharmacodynamic characteristics of PEG-IFN in these patients.

RESULTS

The dose-limiting toxicity (DLT) as defined by the protocol was not achieved at the highest dose tested of 630 mug/wk. With the addition of ara-C, the DLT was reached at 540 microg/wk. The safety profile was similar to that of unmodified IFNs. Of 27 patients treated with PEG-IFN, 14 (52%) achieved or maintained a complete hematologic response and three (11%) achieved a complete cytogenetic response. Among 16 patients treated with the combination of PEG-IFN and ara-C, 11 (69%) achieved or maintained complete hematologic remission and two (13%) achieved complete cytogenetic remission. The mean serum peak concentration (C(max)) of PEG-IFN increased from 9.4 to 28 ng/mL as the dose increased from 270 to 450 microg/wk, with no further increases in C(max) at higher dose levels. Serum concentration reached peak value starting about 48 hours after drug administration and was maintained at close to peak value throughout the dosing interval. The mean +/- SD area under the serum concentration-time curve (AUC) calculated after the first dose also increased from 1,022 +/- 694 to 3,343 +/- 2,728 ng hour/mL as dose was increased from 270 to 450 microg/wk, showing a dose-related increase in systemic exposure of PEG-IFN. As with C(max), the AUC did not increase at higher dose levels. The maximum induction (E(max)) of neopterin, the surrogate marker of the pharmacodynamic activity of PEG-IFN, increased from 120% to 361% over baseline values as the dose was increased from 270 to 540 microg/wk. On the once-weekly multiple dosing schedule, both the PEG-IFN and neopterin concentration seemed to reach steady state by week 5 and the steady-state values were maintained with chronic dosing over 6 months.

CONCLUSION

Pegasys provided a significant advantage over standard IFN-alpha by enabling once-weekly dosing while maintaining acceptable safety, tolerability, and activity profiles. This branched 40-kDa PEG-IFN was well tolerated both as a monotherapy as well as in combination with ara-C. Demonstration of its sustained exposure, pharmacodynamic activity, hematologic response, and evidence of cytogenetic response in several patients in this limited study with either IFN-refractory or INF-intolerant patients provides a promise for further investigation in combination with new agents like imatinib.

A phase-II study of pegylated interferon alfa-2b for patients with metastatic renal cell carcinoma and removal of the primary tumor

Twenty-two patients with metastatic renal cell carcinoma and removal of the primary tumor were treated with subcutaneous pegylated interferon alfa-2b (PEG-Intron) to evaluate toxicity and efficacy. Start dose was 3.0 microg/kg/week, escalated to 6.0 microg/kg/week. After 2 months, therapy was extended in case of response or stable disease (SD) until progressive disease (PD) or relapse for a maximum of 2 years. National Cancer Institute common toxicity criteria (NCI-CTC) were monitored every 2-4 weeks. After 2 months, nine patients did not continue (8 PD, 1 SD with grade 4 CTC) and 13 extended treatment [three partial response (PR), 10 SD], of these, 11 progressed. One patient with PR developed a durable complete response later. Overall response rate was 13.6% (3/22). Median overall survival is 13 months (range 3-35 months). Dosage was escalated to 6 microg/kg/week in three patients. NCI-CTC grade 2 and 3 required dose attenuation in 12 patients during escalation, and reduction in 10 during the trial. Three patients discontinued because of grade 4 CTC (two fatigue, one hyperglycemia). Fatigue was the major dose-limiting toxicity. These results suggest an efficacy and toxicity of PEG-Intron comparable to standard interferon alfa-2b in patients with mRCC and removal of the primary tumor.

New pharmacokinetic and pharmacodynamic tools for interferon-alpha (IFN-alpha) treatment of human cancer

Interferon alpha (IFN-alpha) has been widely used in the treatment of human solid and haematologic malignancies. Although the antitumour activity of IFN-alpha is well recognised at present, no major advances have been achieved in the last few years. Recent findings have provided new information on the molecular mechanisms of the antitumour activity of the cytokine. In fact, IFN-alpha appears to block cell proliferation, at least in part, through the induction of apoptotic effects. This cytokine can also regulate the progression of tumour cells through the different phases of the cell cycle inducing an increase of the expression of the cyclin-dependent kinase inhibitors p21 and p27. However, it must be considered that IFN-alpha is a physiologic molecule with ubiquitously expressed receptors that is likely to activate survival mechanisms in the cell. We have recently identified an epidermal growth factor (EGF) Ras-dependent protective response to the apoptosis induced by IFN-alpha in epidermoid cancer cells. The identification of tissue- and/or tumour-specific survival pathways and their selective targeting might provide a new approach to improve the efficacy of IFN-alpha-based treatment of human cancer. Moreover, new pegylated species of IFN-alpha are now available with a more favourable pharmacokinetic profile. We will review these achievements, and we will specifically address the topic of IFN-alpha-based molecularly targeted combinatory antitumour approaches.

Pegylated and Conventional Interferon-α Induce Comparable Transcriptional Responses and Inhibition of Tumor Growth in a Human Melanoma SCID Mouse Xenotransplantation Model

Interferon-alpha (IFN-alpha) is widely used for the treatment of viral infections and primary cancers. In the present study, we investigated whether the anti-proliferative activity of IFN-alpha is capable of inhibiting melanoma tumor development in the absence of protective immune responses in a severe combined immunodeficiency (SCID) mouse model. Mice treated with either regular (100 microg/3 times per week) or pegylated (300 microg/once weekly) human IFN-alpha 2a showed a marked reduction in tumor weight after 4 wk of treatment. Tumor weight in pegylated and conventional IFN-alpha-treated animals was reduced by 61% and 67%, respectively, as compared to saline control (both p< or =0.01). A decrease of proliferation and an increase of apoptotic tumor cells were observed in IFN-treated tumors. DNA microarrays were applied to analyze transcriptional responses in tumors after 4 wk of treatment and a subset of about 90 genes was differentially expressed. Twenty-four novel and five known interferon-inducible genes were up- and 65 genes downregulated. A direct comparison of IFN-alpha and pegylated IFN-alpha did not reveal any significant differences in tumor growth inhibition indicating that this novel and more stable class of IFN is functionally equivalent. Despite the structural difference between pegylated and conventional IFN-alpha, both agents caused similar transcriptional responses in human melanoma xenotransplants.

Advances in pretargeting biotechnology

A major focus of current drug research is to improve drug targeting to internal target sites such as to solid tumors or specific organs. The objective of drug targeting, especially for cancer chemotherapy and radioimmunotherapy, is to enhance the effectiveness of the drug by concentrating it at the target site and minimizing its effects in nontarget sites. Although tumor targeting has been obtained with large long-circulating radiolabeled antibody molecules, normal organ activity, especially in the blood kidneys, liver, and bone marrow is a significant problem. Over the last 20 years, studies to improve the therapeutic use of antibodies have included the use of antibody fragments, chase molecules, metabolizable linkers, antibody-directed enzyme prodrugs (ADEPT), local delivery, and pretargeting. Here, we will review the most interesting recent advances in pretargeting biotechnology.

High Level Activity of 2', 5'-Oligoadenylate Synthetase in Dog Serum

Most animal cells that are exposed to interferon (IFN) experience an increase in the activity of 2', 5'-oligoadenylate synthetase (OAS), which is an important effector of IFN's antiviral action. OAS activity has been widely used in clinical chemistry as an indicator of IFN activity. In this study, we found that OAS activity in canine serum is 46.0 +/- 40.4 nmol/dl/hr, which is 10- to 100-fold higher than in other animals such as the cat (1.9 +/- 2.1), rabbit (4.0 +/- 1.1), and guinea pig (0.3 +/- 0.6). The canine OAS protein was detected by Western blotting using a 68M-10 monoclonal anti-murine OAS antibody, and was found to be composed of at least three distinct molecular species of p40 class OAS. Among these, the 40 and 42 kDa components were determined to be the major species in serum and fibroblast cell lines, respectively.

Interferon Alfa-2b Three Times Daily and Thalidomide in the Treatment of Metastatic Renal Cell Carcinoma

Purpose: The antiangiogenic effect of interferon (IFN) may improve with frequent dosing and by combination with other agents with antiangiogenic activity. To evaluate this potential, we treated patients with metastatic renal cell carcinoma (RCC) with frequently dosed IFN and thalidomide.

Patients and Methods: Thirty patients were given IFN-α-2b 0.9 MU subcutaneously three times daily for 1 month and subsequently 1.2 MU tid unless serious toxicity was encountered. Thalidomide was first given 100 mg/d for 1 week and 300 mg/d thereafter. Sera were collected before and during treatment for serum vascular endothelial growth factor (S-VEGF) analyses performed using enzyme-linked immunosorbent assay.

Results: The intention-to-treat response rate was 20% (95% CI, 6% to 34%) and response rate for assessable patients (n = 27) was 22% (95% CI, 6% to 38%). All responses were partial. In addition, 17 patients (63%; 95% CI, 45% to 81%) had stable disease for 3 months or longer. The median time to treatment failure was 7.7 months, and median survival time was 14.9 months. The most common cause of thalidomide discontinuation was neuropathy. S-VEGF levels decreased more in patients who responded to therapy compared with those in patients whose condition had stabilized or who had progressive disease (P = .036).

Conclusion: The combination of frequently dosed IFN-α-2b and low-dose thalidomide is feasible and active in advanced RCC, but the clinical benefit may remain small compared with that of IFN alone. Results from an ongoing phase III trial comparing IFN-α with or without thalidomide need to be analyzed before this combination can be recommended for use outside clinical studies.

Response assessment classification in patients with advanced renal cell carcinoma treated on clinical trials

BACKGROUND

The objective of the current study was to evaluate the effect on response assessment classification in patients with metastatic renal cell carcinoma (RCC) using unidimensional (Response Evaluation Criteria in Solid Tumors) and bidimensional (World Health Organization) criteria, including or excluding measurements of the primary renal tumor and using a new index to compensate for the disproportionate effect of large renal tumors relative to their metastases.

METHODS

Fifty-three imaging studies involving a total of 44 patients with metastatic RCC who were treated on clinical trials of interferon-alpha analogue and/or thalidomide were reviewed retrospectively. The best overall response assessment and progression free survival were calculated with both unidimensional and bidimensional tumor measurements. Patients were then stratified into two groups: patients with primary renal tumors in situ and patients who underwent resection of their primary renal tumors. The best overall response and the time to disease progression were calculated based on the sum of measurements (conventional methodology), both including and excluding the primary tumor. A new method of response assessment, the 'normalized lesion index', which equalizes the differences in tumor size for an individual patient, was evaluated and compared with the conventional response assessment.

RESULTS

There was an 11% disagreement rate in the best overall response assessment between unidimensional and bidimensional measurements. The time to progression was 9.2 months measured unidimensionally, compared with 6.4 months assessed bidimensionally. In the group of patients who had primary renal tumors in situ, using the conventional sum of measurements method, the apparent time to progression was an average of 4.2 months longer compared with measurements that did not include the primary renal tumor. The use of the normalized lesion index method resulted in an improved concordance in best overall response assessments and similar time to progression assessments when the primary renal tumor was included compared with patients who did not have primary renal tumors in situ.

CONCLUSIONS

The use of unidimensional measurements in RCC therapy assessment results in significantly different time to progression classification compared with the use of bidimensional measurements. Response assessment classification in patients with RCC is affected by the exclusion or inclusion of measurements of the primary renal tumor. The normalized lesion index warrants further study in assessing response in patients with metastatic RCC and other solid tumor malignancies that often show substantial differences in sizes of measurable lesions.

Cytokine-based therapy for metastatic renal cell cancer

The use of recombinant gene technology to produce commercially available amounts of cytokines heralded an era of clinical applications of immunotherapy. Although the response rates to cytokine therapies are modest and sometimes occur at the expense of great cost and toxicity, they are proof of the principal that even large tumor burdens can be overcome by purely immune modulation. The interleukins and the interferons have been used in various phases of clinical trials in RCC. The maturation and final results of phase III trials are needed to guide clinical practice. In the meantime, the knowledge gained clinically and in the laboratory should lead to continued improvements and outcomes in immunotherapy for RCC.

Pegylation: engineering improved biopharmaceuticals for oncology

Pegylation, the technology of polyethylene glycol (PEG) conjugation, holds significant promise in maintaining effective plasma concentrations of systemically administered drugs that might otherwise be hampered in vivo by a number of factors, such as rapid elimination by the kidneys. Mobile, nontoxic PEG chains can be conjugated to biotherapeutics, increasing their hydrodynamic volume, which can in turn prolong their plasma retention time, increase their solubility, and shield antigenic determinants on the drug from detection by the immune system. Attaching PEG molecules for optimal pharmacokinetics without obstructing the active sites that are essential for drug efficacy is a major challenge in pegylation. Current pegylation technology uses linkerless conjugation methods to produce coupling without added toxicity or immunogenicity, and may keep the innate surface charge of the pegylated molecule intact. In addition to controlling the size and complexity of PEG molecules, the attachment site can be manipulated to avoid steric hindrance of the drug's active receptor-recognition or substrate-interaction site. A few pegylated drugs have been engineered to have an improved pharmacokinetic profile with preserved bioactivity. They often have prolonged steady plasma concentrations in vivo, thereby making a reduced number of doses possible. Other interesting effects have also emerged, such as the self-regulating pharmacokinetics of pegfilgrastim, a pegylated version of the granulocyte colony-stimulating factor filgrastim that is administered for management of chemotherapy-induced neutropenia. The improved dosing schedule, with longer intervals between administrations of the pegylated agents, will improve compliance and quality of life in patients with chronic disease.

Prognostic factors and clinical trials of new agents in patients with metastatic renal cell carcinoma

Metastatic renal cell carcinoma (RCC) remains a disease highly resistant to systemic therapy. Results of recent reports in the literature on prognostic factors and clinical trials for patients with metastatic RCC were reviewed. Small numbers of patients exhibit complete or partial responses to interferon and/or interleukin-2, but most patients do not respond and there are few long-term survivors. Therefore, the identification of new agents with better antitumor activity against metastases remains the highest priority of clinical investigation in this refractory tumor. Prospective identification of patients more likely to benefit from cytokine therapy could be used as a stratification factor in Phase III trials, and in risk-directed therapy.

Renal cell carcinoma

Renal cell carcinoma (RCC) continues to present a diagnostic and therapeutic challenge. The increased use of abdominal imaging studies does not appear to completely account for the rising incidence of RCC. Alcohol consumption has been found to be a possible protective factor among women in a recent study, but among women with children, RCC risk may increase with each child born when compared with nulliparous women. An alternative staging system shows promise, and two randomized clinical trials clarify the role of removing the primary tumor in the setting of metastatic RCC. New agents have shown promise in early clinical trials such as CCI-779, pegylated interferon, thalidomide, and anti-VEGF antibody.

Novel therapies for renal cell carcinoma--an update

This article reviews the recent progress in the search for new treatments for renal cell cancer (RCC), based on a variety of preclinical models or strategies. Some recent clinical trials addressing migrating treatments from other cancers onto RCC and novel agents are discussed, as well as the molecular targets for some of the novel agents. Drugs oriented to histologically definable RCC features, such as the G250 antigen, and the receptor tyrosine kinases, such as epidermal growth factor receptor, are reviewed. Drugs aimed at antiangiogenesis and perturbing features of the cell cycle are also mentioned, including preclinical and empirical experience. Molecular techniques in the study of von Hippel Lindau-related pathways and mRNA expression analyses are cited. Within the immune model of therapy, progress in the application of immune-related drugs including older cytokines (IL-2, IFN-alpha) and of newer cytokine-variant and other cytokines are discussed. Finally, cell-based therapies such as lymphocyte infusions, tumour-cell vaccines, dendritic cell vaccines and allogeneic mini-transplant are outlined. Although high percentage improvements in outcomes for metastatic RCC are not yet realised, the many fronts for scientific and clinical advances form some basis for optimism in the coming years.

Polyethylene glycol-conjugated adenosine phosphorylase: development of alternative enzyme therapy for adenosine deaminase deficiency

Purine nucleoside phosphorylase had previously been engineered to accept 6-amino substituted purine nucleosides by two active site substitutions, Asn243Asp; Lys244Gln. In the present study, recombinant adenosine phosphorylase (AP) has been conjugated to branched polyethylene glycol (PEG) polymers of approximately 42.5 kDa. Matrix-assisted laser desorption/ionization analysis and SDS acrylamide electrophoresis analysis indicated a subunit composition of greater than 205 kDa consistent with the conjugation of as many as four PEG molecules per AP subunit. The PEG-conjugated enzyme retained greater than 90% of the native catalytic activity. Administration of the enzyme to mice demonstrated the PEG-AP to have a 67-fold increased plasma half-life compared to the native enzyme, 65.1+/-2.9 h versus 57.8+/-1.1 min, respectively. PEG-AP was principally confined to the plasma with minimal activity detected in tissues and of these spleen had the greatest activity and essentially no activity was found in urine. PEG-AP has retained activity with inosine and its injection into PNP-deficient mice resulted in a 2.7-fold increase in urine urate. AP was also shown to protect human CEM cells in culture from the toxic effects of 2'-deoxyadenosine. These studies provide evidence for consideration of PEG-AP as an alternative enzyme therapy for the inherited deficiency of adenosine deaminase.

Perspectives of pegylated interferon use in dermatological oncology

The potent immunomodulatory, antiproliferative and antiviral properties of interferons (IFNs), together with their availability in large amounts thanks to the recombinant DNA technique, have resulted in their widespread clinical use in a variety of viral and nonviral proliferative disorders. In dermato-oncology, IFNs have been used primarily in melanoma, but also in nonmelanoma skin cancer, such as squamous and basal cell carcinomas, Kaposi sarcomas and lymphomas. Trials with IFNs have been performed in patients with melanoma in an adjuvant setting (stage II and III) and in metastatic disease (stage IV). While the response rates with IFNs as single agents in stage IV disease usually do not exceed 15%, the use of adjuvant IFNs has been claimed to increase disease-free survival (stage II), or even overall survival (stage III), in low- or high-dose regimens, respectively; the latter, however, involved numerous side-effects and were beset with lack of compliance and acceptance, as well as being very costly. Pegylated IFN (PEG-IFN) is a form of recombinant human IFN that has been chemically modified by the covalent attachment of a branched metoxpolyethylene glycol moiety. Pharmacogenetic and pharmacodynamic data obtained in animal and in phase I studies have indicated that PEG-IFN injected once a week has the potential to be superior in efficacy to human IFN injected three times a week. The safety profiles of PEG-IFN and IFN are comparable in healthy volunteers and in chronic hepatitis C (CHC) patients. PEG-IFN is currently being evaluated for the treatment of CHC, renal cell carcinoma, chronic myelogenous leukaemia, and malignant melanoma, the last in both stage IV and stage III disease.

Pharmacokinetic and pharmacodynamic studies of a human serum albumin-interferon-alpha fusion protein in cynomolgus monkeys

Interferon-alpha (IFN-alpha) is indicated for the treatment of certain viral infections including hepatitis B and C, and cancers such as melanoma. The short circulating half-life of unmodified IFN-alpha makes frequent dosing (daily or three times weekly) over an extended period (6-12 months or more) necessary. To improve the pharmacokinetics of IFN-alpha and decrease dosing frequency, IFN-alpha was fused to human serum albumin producing a new protein, Albuferon. In vitro comparisons of Albuferon and IFN-alpha showed similar antiviral and antiproliferative activities, although Albuferon was less potent on a molar basis than IFN-alpha. Pharmacokinetic and pharmacodynamic properties of the fusion protein were enhanced in monkeys. After a single intravenous injection (30 microg/kg,) clearance was 0.9 ml/h/kg, and the terminal half-life was 68 h. After 30 microg/kg subcutaneous injection, apparent clearance (clearance divided by bioavailability) was 1.4 ml/h/kg, the terminal half-life was 93 h, and bioavailability was 64%. The rate of clearance of Albuferon was approximately 140-fold slower, and the half-life 18-fold longer, than for IFN-alpha given by the subcutaneous route in other monkey studies. Sera from Albuferon-treated monkeys demonstrated dose-related antiviral activity for > or =8 days based on an in vitro bioassay, whereas antiviral activity from IFN-alpha-treated animals was only slightly elevated relative to vehicle on day 0. Significant increases in 2',5'-oligoadenylate synthetase mRNA relative to IFN-alpha- or vehicle-treated animals were maintained for > or =10 days after subcutaneous dosing. The improved pharmacokinetics of Albuferon are accompanied by an improved pharmacodynamic response suggesting that Albuferon may offer the benefits of less frequent dosing and a potentially improved efficacy profile compared with IFN-alpha.

Phase II trial of branched peginterferon-alpha 2a (40 kDa) for patients with advanced renal cell carcinoma

BACKGROUND

Peginterferon-alpha 2a (40 kDa), PEGASYS(TM) (PEG-IFN), is a modified form of recombinant human interferon (IFN)-alpha 2a with sustained absorption and prolonged half-life after subcutaneous administration. A phase II trial was conducted in previously untreated patients with advanced renal cell carcinoma (RCC) to assess efficacy, toxicity and pharmacokinetic profile.

PATIENTS AND METHODS

Forty previously untreated patients with advanced RCC were enrolled on this multicenter trial. The median age was 60 years and 63% had prior nephrectomy. PEG-IFN was administered at a dose of 450 micro g/week on a weekly basis by subcutaneous injection. Serial venous blood samples were drawn to assess concentrations of PEG-IFN.

RESULTS

Five (13%) patients achieved a major response (four partial and one complete). The median time to progression was 3.8 months, and 63% of patients were alive at 1 year. The toxicity profile was mostly mild to moderate in intensity. Toxicity higher than grade 2 included neutropenia (six patients), fatigue/asthenia (four patients), nausea/vomiting (three patients) and elevated hepatic transaminase concentrations (four patients). Serum drug levels were studied in all patients; mean C(max) at week 1 was 19 ng/ml, and levels were sustained at close to peak over 1 week. With chronic dosing, drug concentration was increased 3-fold, and steady state was achieved in 5-9 weeks.

CONCLUSIONS

The sustained maintenance of serum levels of PEG-IFN allows once-weekly dosing. The efficacy and tolerability profile was qualitatively similar to standard IFN-alpha, and adverse events were mostly mild to moderate in nature.

Pegylated interferon alfa-2b treatment for patients with solid tumors: a phase I/II study

PURPOSE

The efficacy of interferon alfa has been established in treating advanced melanoma and renal cell carcinoma (RCC) patients. We conducted a phase I/II study to determine the maximum-tolerated dose (MTD), the safety and tolerability, and the preliminary efficacy of once-weekly pegylated interferon alfa-2b (IFNalpha-2b) in patients with advanced solid tumors (primarily RCC).

PATIENTS AND METHODS

To determine the MTD, 35 patients with a variety of advanced solid tumors received 0.75 to 7.5 micro g/kg/wk of pegylated IFNalpha-2b by subcutaneous injection for 12 weeks. An additional 35 previously untreated RCC patients received 6.0 and 7.5 micro g/kg/wk for up to 12 weeks. Patients with a response or stable disease after 12 weeks were eligible for the extension protocol and were treated for up to 1 year or until disease progression.

RESULTS

The MTD for pegylated IFNalpha-2b at 12 weeks was 6.0 micro g/kg/wk. One year of 6.0 micro g/kg/wk was well tolerated with appropriate dose modification; no grade 3 or 4 fatigue occurred, and safety was comparable with that with nonpegylated IFNalpha-2b. The most common nonhematologic adverse events included mild to moderate nausea, anorexia, and fatigue. Six patients had grade 3 or 4 hematologic toxicity. Twenty-nine patients continued on the extension protocol. Four patients had a complete response, and five patients had a partial response. Among 44 previously untreated RCC patients, the objective response rate was 14%. Median survival for all RCC patients was 13.2 months.

CONCLUSION

Pegylated IFNalpha-2b was active and well tolerated in patients with metastatic solid tumors, including RCC, at doses up to 6.0 micro g/kg/wk.

Early viral clearance and sustained response in chronic hepatitis C: a controlled trial of interferon and ribavirin after high-dose interferon induction

High-dose induction with alpha-interferon induces early viral clearance of hepatitis C and combined with ribavirin enhances sustained response. We assess whether adding ribavirin after viral clearance obtained by alpha-interferon induction increased the rate of viral eradication.Forty-one naïve patients with chronic hepatitis C were randomised to receive, after 4 weeks of 10 mU daily of alpha-interferon (induction), 3 mU daily for 22 weeks and 3 mU thrice weekly for 26 weeks of either interferon alone (monotherapy) or interferon plus 1000-1200 mg daily of ribavirin (combination therapy). At the end of the induction phase, 23 (56%) subjects had cleared HCV-RNA. During therapy, breakthrough was observed in four patients on monotherapy, but never in patients on combination therapy. The rate of clearance of HCV-RNA was different between monotherapy and combination therapy at the end of treatment (40% vs. 76.1%, P=0.02) and at the end of follow-up (5% vs. 57.1%, P=0.001). Twelve of the 23 patients who cleared HCV-RNA during induction, but only one of the 18 still HCV-RNA-positive after 4 weeks of therapy, had a sustained response (52.2% vs. 5.6%, P=0.001). Clearance of HCV-RNA at 1 week had a high positive predictive value for sustained response in combination therapy (PPV=0.75), but not in monotherapy (PPV=0.33). Induction with high daily doses of alpha-interferon obtains suppression of hepatitis C in more than half of patients, but ribavirin is needed to maintain a sustained response. The rate of sustained response is a function of the time to HCV-RNA clearance. In patients not responding to induction therapy addition of ribavirin does not obtain a sustained virological response.

Immunotherapy of metastatic renal cell cancer

BACKGROUND

The management of metastatic renal cancer remains a therapeutic challenge. Conventional cytotoxic chemotherapy is rarely effective, and the most promising approaches appear to lie in the field of immunotherapy.

METHODS

The authors review the literature regarding current and investigational immunotherapy approaches to the management of metastatic renal cancer.

RESULTS

The mechanism of action, methods of delivery, efficacy, and side effect profile of the cytokines IL-2 and interferon alfa are discussed. The role of investigational approaches such as tumor vaccines, antibody-based therapy, lymphocyte infusions, and bone marrow transplantation is addressed. The rationale for nephrectomy as an adjunctive procedure to immunotherapy is also discussed.

CONCLUSIONS

Ongoing laboratory investigation of the cause of the immune deficit in patients with metastatic renal cell cancer will result in the development of novel therapies to enhance tumor cell recognition as well as host antitumor response. Translation of laboratory findings into the clinic will be facilitated by the presence of an already well-developed infrastructure for the performance of clinical trials for patients with this difficult diagnosis.