Pharmacodynamics of biological response in vivo after single and multiple doses of interferon-beta

Ingested (oral) adrenocorticotropic hormone (ACTH) inhibits interleukin-17 in the central nervous system after adoptive transfer of T helper (Th)1/Th17 T cells in the mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis

BACKGROUND

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory autoimmune disease of the central nervous system (CNS) that resembles multiple sclerosis (MS) and provides a useful animal model for the evaluation of mechanisms of action for potential immunomodulatory therapies. We have previously shown that oral adrenocorticotropic hormone (ACTH) decreased either interleukin (IL)-17 and/or interferon (IFN)γ in the CNS during EAE.

OBJECTIVE

We wanted to examine whether oral ACTH showed a preferential effect on Th17 as opposed to Th1 phenotypes.

DESIGN/METHODS

We therefore examined whether oral ACTH could inhibit EAE in the C57BL/6 (B6) mouse strain after adoptive transfer of equal quantities of Th17 (CD4+IL-17+) and Th1 (CD4+IFN-γ+) T cells generated after in vitro skewing. B6 mice were injected with a 1:1 ratio of Th1:Th17 T cells and were gavaged daily with control scrambled peptide (s-MSH) or 10 μg ACTH.

RESULTS

Ingested (oral) ACTH attenuated ongoing clinical EAE disease and decreased the frequencies of Th17 cells in the spleen and in the CNS, but not Th1.

CONCLUSIONS

These findings suggest that there was preferential regulation of Th17 cells by oral ACTH compared to Th1 T cells in the CNS.

Considerations for Use of Pharmacodynamic Biomarkers to Support Biosimilar Development - (III) A Randomized Trial with Interferon Beta-1a Products

The US Food and Drug Administration (FDA) has taken steps to bring efficiency to the development of biosimilars, including establishing guidance for the use of pharmacokinetic and pharmacodynamic (PD) similarity study data without a comparative clinical study with efficacy end point(s). To better understand the potential role for PD biomarkers in biosimilar development and inform best practices for biomarker selection and analysis, we conducted a randomized, double-blinded, placebo-controlled, single-dose, parallel-arm clinical study in healthy participants. Eighty-four healthy participants (n = 12 per dose arm) received either placebo or one of three doses of either interferon β-1a (7.5-30 μg) or pegylated interferon β-1a (31.25-125 μg) to evaluate the maximum change from baseline and the baseline-adjusted area under the effect curve for the biomarkers neopterin in serum and myxovirus resistance protein 1 in blood. Both PD biomarkers increased following product administration with clear separation from baseline (neopterin: 3.4-fold and 3.9-fold increase for interferon β-1a and pegylated interferon β-1a, respectively; myxovirus resistance protein 1: 19.0-fold and 47.2-fold increase for interferon β-1a and pegylated interferon β-1a, respectively). The dose-response curves support that therapeutic doses were adequately sensitive to detect differences in both PD biomarkers for consideration in a PD similarity study design. Because baseline levels of both biomarkers are low compared with on-treatment values, there was little difference in using PD measures adjusted to baseline compared with the results without baseline adjustment. This study illustrates potential methodologies for evaluating PD biomarkers and an approach to address information gaps when limited information is publicly available for one or more PD biomarkers.

Type I interferons in pancreatic cancer and development of new therapeutic approaches

Immunotherapy has emerged as a new treatment strategy for cancer. However, its promise in pancreatic cancer has not yet been realized. Understanding the immunosuppressive tumor microenvironment of pancreatic cancer, and identifying new therapeutic targets to increase tumor-specific immune responses, is necessary in order to improve clinical outcomes. Type I interferons, e.g. IFN-α and -β, are considered as an important bridge between the innate and adaptive immune system. Thereby, type I IFNs induce a broad spectrum of anti-tumor effects, including immunologic, vascular, as well as direct anti-tumor effects. While IFN therapies have been around for a while, new insights into exogenous and endogenous activation of the IFN pathway have resulted in new IFN-related cancer treatment strategies. Here, we focus on the pre-clinical and clinical evidence of novel ways to take advantage of the type I IFN pathway, such as IFN based conjugates and activation of the STING and RIG-I pathways.

Ingested ACTH blocks Th17 production by inhibiting GALT IL-6

BACKGROUND

EAE is an inflammatory autoimmune process of the CNS that resembles multiple sclerosis (MS) and provides a useful animal model for the evaluation of mechanisms of action for potential immunomodulatory therapies. Oral ACTH (adrenocorticotropic hormone) can decrease clinical disease, IL-17 and Th1-like encephalitogenic IFN-γ secretion and increase Treg frequency. The mechanism by which oral ACTH decreases inflammatory proteins and increases Treg cell frequencies is unknown.

OBJECTIVE

IL-6 is a pivotal cytokine in the gut that determines the relative frequencies of Th17 vs Treg cells. We examined whether oral ACTH inhibited IL-6 in the gut associated lymphoid tissue (GALT) in EAE.

DESIGN/METHODS

B6 mice were immunized with MOG peptide 35-55 and gavaged with scrambled ACTH (scrambled melanocyte stimulating hormone [scrambled α-MSH]) or ACTH 1-39 during ongoing disease.

RESULTS

Ingested (oral) ACTH inhibited ongoing clinical disease. In the lamina propria (LP) immune compartment, there were significantly less CD11b + IL-6 and IL-17 producing lymphocytes from ACTH fed mice compared to s-MSH fed mice. There was also a decrease in the frequency of IL-17 and IFN-γ producing spleen cells and an increase in CD4 + FoxP3+ Treg cell frequency in ACTH fed mice compared to s-MSH fed control spleens. There were less IFN-γ producing CNS lymphocytes in ACTH fed mice compared to s-MSH fed control CNS.

CONCLUSIONS

Ingested ACTH inhibits EAE clinical disease by inhibiting IL-6 in the GALT.

Treatment of Experimental Autoimmune Encephalomyelitis by Sustained Delivery of Low-Dose IFN-α

Multiple sclerosis (MS) is a chronic autoimmune disease with no curative treatment. The immune regulatory properties of type I IFNs have led to the approval of IFN-β for the treatment of relapsing-remitting MS. However, there is still an unmet need to improve the tolerability and efficacy of this therapy. In this work, we evaluated the sustained delivery of IFN-α1, either alone or fused to apolipoprotein A-1 by means of an adeno-associated viral (AAV) system in the mouse model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. These in vivo experiments demonstrated the prophylactic and therapeutic efficacy of the AAV-IFN-α or AAV-IFN-α fused to apolipoprotein A-1 vectors in experimental autoimmune encephalomyelitis, even at low doses devoid of hematological or neurologic toxicity. The sustained delivery of such low-dose IFN-α resulted in immunomodulatory effects, consisting of proinflammatory monocyte and T regulatory cell expansion. Moreover, encephalitogenic T lymphocytes from IFN-α-treated mice re-exposed to the myelin oligodendrocyte glycoprotein peptide in vitro showed a reduced proliferative response and cytokine (IL-17A and IFN-γ) production, in addition to upregulation of immunosuppressive molecules, such as IL-10, IDO, or PD-1. In conclusion, the results of the present work support the potential of sustained delivery of low-dose IFN-α for the treatment of MS and likely other T cell-dependent chronic autoimmune disorders.

Randomized study of once-weekly interferon β-1a therapy in relapsing multiple sclerosis: three-year data from the OWIMS study

Background: Once weekly interferon β-1a for multiple sclerosis (OWIMS) demonstrated modest, but significant, magnetic resonance imaging (MRI) benefit of once-weekly (qw) interferon (IFN) β-1a at 48 weeks, but no significant effect on relapses. Objective: An OWIMS extension permitted assessment of longer-term efficacy/safety of qw IFN β-1a in relapsing-remitting multiple sclerosis (RRMS). Methods: Placebo patients were rerandomized to IFN β-1a, 22 or 44 mcg qw, for two additional 48-week intervals. Primary outcome was MRI lesion activity. Relapse rate and other MRI measures were secondary outcomes. Results: After three years, median (mean) T2 lesion count/patient/scan was 1.3 (2.6) for 44 mcg, 1.7 (3.3) for 22 mcg, 1.7 (3.4) for placebo/22 mcg, 2.0 (3.6) for placebo/44 mcg (all differences not significant). Annualized relapse rates were lowest for 44 mcg (0.77) versus other groups (0.83-0.86, not significant). Persistent neutralizing antibodies did not affect relapse rates, but MRI active lesions were increased in antibody-positive patients receiving 44 mcg compared to antibody negative patients. Conclusions: In RRMS, once weekly IFN β-1a, particularly 44 mcg, can induce a significant MRI, but not relapse, effect, compared with placebo. No significant dose effect was seen. In contrast to the significant effect observed with three-times-weekly dosing of subcutaneous IFN β-1a compared with placebo, this study confirms the lack of meaningful clinical benefit with once-weekly dosing.

Interferons and their stimulated genes in the tumor microenvironment

Constitutive expression of interferons (IFNs) and activation of their signaling pathways have pivotal roles in host responses to malignant cells in the tumor microenvironment. IFNs are induced by the innate immune system and in tumors through stimulation of Toll-like receptors (TLRs) and through other signaling pathways in response to specific cytokines. Although in the oncologic context IFNs have been thought of more as exogenous pharmaceuticals, the autocrine and paracrine actions of endogenous IFNs probably have even more critical effects on neoplastic disease outcomes. Through high-affinity cell surface receptors, IFNs modulate transcriptional signaling, leading to regulation of more than 2,000 genes with varying patterns of temporal expression. Induction of the gene products by both unphosphorylated and phosphorylated STAT1 after ligand binding results in alterations in tumor cell survival, inhibition of angiogenesis, and augmentation of actions of T, natural killer (NK), and dendritic cells. The interferon-stimulated gene (ISG) signature can be a favorable biomarker of immune response but, in a seemingly paradoxical finding, a specific subset of the full ISG signature indicates an unfavorable response to DNA-damaging interventions such as radiation. IFNs in the tumor microenvironment thus can alter the emergence, progression, and regression of malignancies.

Site-specific PEGylation enhances the pharmacokinetic properties and antitumor activity of interferon beta-1b

Interferon beta (IFN-β) is widely used to ameliorate disease progression in patients with Multiple Sclerosis. IFN-β has a short half-life in humans, necessitating frequent administration for optimum effectiveness. Covalent modification of IFN-β with polyethylene glycol (PEG) improves the pharmacokinetic properties of the protein, but can adversely affect the protein's in vitro bioactivity. Random modification of lysine residues in IFN-β with amine-reactive PEGs decreased the in vitro bioactivity of the protein 50-fold, presumably due to modification of lysine residues near critical receptor binding sites. PEGylated IFN-β proteins that retained high in vitro bioactivity could be obtained by selective modification of the N-terminus of the protein with PEG. Here we use site-specific PEGylation technology (targeted attachment of a cysteine-reactive-PEG to an engineered cysteine residue in IFN-β) to identify several additional amino acid positions where PEG can be attached to IFN-β without appreciable loss of in vitro bioactivity. Unexpectedly, we found that most of the PEG-IFN-β analogs showed 11- to 78-fold improved in vitro bioactivities relative to their unPEGylated parent proteins and to IFN-β-1b. In vivo studies showed that a lead PEG-IFN-β protein had improved pharmacokinetic properties compared to IFN-β and was significantly more effective than IFN-β at inhibiting growth of a human tumor xenograft in athymic mice.

Interferon lambda as a potential new therapeutic for hepatitis C

Interferon lambdas (IFN-lambda) are Type III interferons with biological activity, including induction of antiviral genes, similar to Type I IFNs, but signal through a distinct receptor complex. The expression pattern for the IFN-lambda receptor is more cell specific than the widely distributed IFN-alpha receptor, suggesting in vivo, IFN-lambda may have fewer side effects than IFN-alpha, such as less hematologic toxicities. A PEGylated form of IFN-lambda (PEG-rIL-29) was well tolerated in animals and did not result in hematologic toxicity. Clinical data from initial studies of PEG-rIL-29 has demonstrated antiviral effects in patients with hepatitis C without producing hematologic toxicity. These preclinical and early clinical data support PEG-rIL-29 as a potential new therapeutic agent for treatment of patients with hepatitis C.

Pharmacogenomics of IFN-beta in multiple sclerosis: towards a personalized medicine approach

Multiple sclerosis (MS) is an inflammatory disease of the CNS. The clinical presentation of MS is heterogeneous. Interferons (IFNs) were the first agents to show clinical efficacy in the treatment of MS and prolonged treatment is still the best available therapy. Although IFN treatment ameliorates immune dysfunction, the response is partial. Clinical experience indicates that there are responders and nonresponders. This distinction suggests that a subset of patients are insensitive or resistant to the action of IFN. This implies that pharmacodynamic responses may differ between patients, leading to interindividual differences in clinical response. Understanding of the factors that underlie the therapeutic response is key to the identification of predictive markers. Here, we describe novel developments in pharmacogenomics research to improve the understanding of the pharmacological effects of IFN therapy, and the identification of biomarkers that allow stratification of MS patients for their response to IFN-beta. Ultimately, this information will lead to a personalized form of medicine, whereby a specific therapy will be applied that is best suited to an individual patient.

Biological response genes after single dose administration of interferon beta-1b to healthy male volunteers

Treatment with interferon beta-1b (IFNB-1b) is clinically effective in multiple sclerosis patients. However, the mechanism of action is only partially understood, and validated biological response markers are lacking. We assessed IFNB-1b-induced transcriptional changes by microarray technology. Healthy male volunteers received 250 mug IFNB-1b or placebo in a double-blind, randomized controlled trial (n=5 per group). Most transcripts demonstrated peak levels after 6-12 h and returned to baseline after 48 h. We identified 227 differentially regulated genes including novel and previously described markers. This panel may become a valuable tool for development of new IFNB-1b formulations and assessment of clinical drug effects.

Short communication: phase I clinical and gene modulatory evaluation of tamoxifen and IFN-alpha2b

Preclinical studies had determined that tamoxifen and interferon-alpha2b (IFN-alpha2b) synergistically inhibited growth of both estrogen-receptor positive and negative murine tumor xenografts and had combined antiangiogenic effects and that tamoxifen potentiated IFN-stimulated gene (ISG) expression. A phase I trial in 26 patients was conducted using the combination to define tolerance and potentiation of ISG expression. IFN- alpha2b at a dose of 3 x 10(6) units/m(2) daily was given subcutaneously (s.c.), and tamoxifen was initiated as a loading dose of 150 mg/m(2) and then 60 mg/m(2) twice daily on day 8. At this initial dose, reduction of dose of IFN- alpha2b was required in 4 of 11 patients, primarily because of fatigue. Another group of patients was treated with an identical tamoxifen dose but with IFN-alpha2b reduced to 2 x 10(6)/m(2) U; this was better tolerated. As the projected serum tamoxifen level to reduplicate preclinical effects was 300 mg/m(2), dose escalation in a third cohort was undertaken; it had to be discontinued secondary to grade III or IV toxicity in 2 of 2 patients. Increases in products of transcriptionally regulated ISGs, beta (2)-microglobulin, neopterin, and ISG15 were assessed. All ISGs increased after IFN-alpha2b, but only ISG15 had a further significant rise after initiation of tamoxifen. Because at doses not limited by unacceptable toxicities, no marked potentiation of ISGs by tamoxifen could be identified, clinical evaluation of the combination was terminated.

Comparison of three PCR assays for the evaluation of interferon-beta biological activity in patients with multiple sclerosis

BACKGROUND

The gene expression of the myxovirus-resistant protein A (MxA) gene is a sensitive measure of the biological response of therapeutically applied interferon-beta (IFNbeta) and of its reduced bioavailability due to inhibiting factors such as IFNbeta-induced neutralizing antibodies (NAbs).

METHODS

We compared three methods for MxA mRNA quantification in 826 peripheral blood mononuclear cell (PBMC) samples obtained from patients with multiple sclerosis (MS). MxA mRNA measurements were performed using quantitative-competitive (qc)-PCR, real time-PCR, and the new semi-quantitative (sq)-PCR assay (MxA IBRIDOGEN).

RESULTS

According to the treatment status (untreated samples versus NAb-negative treated samples), real time-PCR gave the highest specificity (93%). Slightly lower specificities were obtained with qc-PCR and sq-PCR (both 91%). qc-PCR showed the highest sensitivity (97%) compared with both real time-PCR (94%) and sq-PCR (95%). A positive correlation was found between qc-PCR and real time-PCR measurements (rspearman=0.776; p<0.0001), which also showed 90% agreement based on a statistically calculated threshold. Likewise, sq-PCR evaluations showed 84% and 79% agreement with qc-PCR and real time-PCR measurements, respectively. In addition, we showed a concordance of 89% between three sq-PCR kits.

CONCLUSIONS

All three methods displayed high specificity for MxA gene expression analysis, allowing the detection of patients in whom IFNbeta did not have any biological action. qc-PCR and real time-PCR are both useful during clinical trials demanding quantitative data of biological activity, whereas sq-PCR could prove useful for routine screening purposes because it is easy to perform and can be done in not specialized laboratories.

An open-label safety and drug interaction study of natalizumab (Antegren) in combination with interferon-beta (Avonex) in patients with multiple sclerosis

In this open-label drug-interaction trial, we studied 38 patients with relapsing-remitting multiple sclerosis (MS) who received 3.0 or 6.0 mg/kg of natalizumab as a single intravenous (i.v.) infusion during stable treatment with intramuscular (i.m.) interferon beta-1a 30 microg (IFNbeta-1a; Avonex). To assess the pharmacokinetic (PK) interaction of natalizumab and IFNbeta-1a, serum concentration-time data for both agents were collected and analysed. Biologic response markers of IFNbeta-1a activity, beta2-microglobulin and neopterin, were also assessed to determine effects of natalizumab on IFNbeta-1a pharmacodynamics (PD). Further, safety and immunogenicity were evaluated. The combination of drug therapies was well tolerated. Although natalizumab serum concentrations (and corresponding PK exposure measures) appeared to be somewhat elevated in the presence of IFNbeta-1a, when compared to the same dose (6.0 mg/kg) administered alone in a concurrent comparator study, the differences were generally small and unlikely to be clinically relevant. In general, natalizumab had no apparent clinically relevant effects on the PK or PD properties of IFNbeta-1a. The presence of antibodies to IFNbeta-1a and natalizumab was relatively low. Overall, the study provided safety, immunogenicity, PK and PD data to support a combination strategy for the use of natalizumab and IFNbeta-1a in the treatment of patients with relapsing-remitting MS. A large clinical study is currently in progress to evaluate the efficacy and long-term safety of this combination drug therapy.

Is multiple sclerosis a disease that requires frequent beta interferon dosing?

The three currently available beta interferon products for the treatment of patients with relapsing-remitting multiple sclerosis (RRMS) are administered according to different regimens. Placebo-controlled clinical trials support the efficacy of both alternate-day interferon beta-1b (Betaferon) and once-a-week interferon beta-1a (Avonex), but benefits to patients are probably dependent on the regimen used. Once-weekly administration, perceived to have fewer adverse events and greater convenience, may improve compliance, whereas frequent administration might enhance efficacy. However, more frequent administration is also associated with an increase in neutralising antibody (NAb) production, relative to once weekly treatment. The issue of NAbs is complex, and their clinical relevance, if any, has yet to be fully assessed. Pharmacological evidence suggests that the effects of beta interferon on a number of biological markers is maximised when administered every 48 hours. This might arise as a result of sustained activity in the intracellular molecular signalling pathways regulating beta interferon-induced gene expression. Some evidence suggests that the increase in biological effect at higher more frequent doses is mirrored by improvements in clinical and MRI outcome measures. Two recent comparative studies demonstrated significantly better clinical and magnetic resonance imaging outcomes in patients with RRMS receiving alternate-day high-dose interferon beta-1b (250 micro g subcutaneously) or three-times-weekly high-dose interferon beta-1a compared to those receiving once weekly low-dose interferon beta-1a (30 micro g intramuscularly). Despite some methodological drawbacks, these studies indicate that the benefits of high-dose frequently administered beta interferon on relapse rate are seen soon after beginning treatment. Therefore, it seems appropriate to begin the treatment of RRMS with this dosing regimen.

Combination immunotherapy with a CpG oligonucleotide (1018 ISS) and rituximab in patients with non-Hodgkin lymphoma: increased interferon-alpha/beta-inducible gene expression, without significant toxicity

CpG oligodeoxynucleotides (CpG-ODNs) affect innate and adaptive immune responses, including antigen presentation, costimulatory molecule expression, dendritic cell maturation, and induction of cytokines enhancing antibody-dependent cell-mediated cytotoxicity (ADCC). We conducted a phase 1 study evaluating 4 dose levels of a CpG-ODN (1018 ISS) with rituximab in 20 patients with relapsed non-Hodgkin lymphoma (NHL). Patients received CpG once a week for 4 weeks beginning after the second of 4 rituximab infusions. Adverse events were minimal. Quantitative polymerase chain reaction (PCR) measurements of a panel of genes inducible by CpG-ODN and interferons were performed on blood samples collected before and 24 hours after CpG. A dose-related increase was measured in the expression of several interferon-inducible genes after CpG and correlated with serum levels of 2'-5' oligoadenylate synthetase (OAS), a validated interferon response marker. Genes induced selectively by interferon-gamma (IFN-gamma) were not significantly induced by CpG. In conclusion, we have defined a set of gene expression markers that provide a sensitive measure of biologic responses of patients to CpG therapy in a dose-related manner. Moreover, all the genes significantly induced by this CpG are regulated by type 1 interferons, providing insight into the dominant immune mechanisms in humans. CpG treatment resulted in no significant toxicity, providing rationale for further testing of this exciting combination immunotherapy approach to NHL.

Biological activity of interferon betas in patients with multiple sclerosis is affected by treatment regimen and neutralising antibodies

BACKGROUND

MxA gene expression is one of the most appropriate markers of biological activity of exogenous interferon (IFN) beta.

METHODS

We quantified MxA mRNA for five consecutive days in 62 patients treated with IFN beta (16, Avonex; 10, Betaferon; 24, Rebif 22; 12, Rebif 44), by quantitative-competitive polymerase chain reaction. Every three months, IFN beta induced neutralising antibodies (NAbs) were evaluated in sera using a cytopathic effect assay.

RESULTS

Two categories of patients were identified: one group (49/62) had a sharp post-injection increase in MxA expression (defined as "IFN beta biological responder"), whereas the other group (13/62) had no MxA induction after IFN beta administrations (defined as "IFN beta biological non-responder"). In 11/13 biological non-responders, the persistent presence of NAbs correlated with abolished biological activity, independently of treatment regimen. The two remaining IFN beta biological non-responders were NAb-. Among the 49 IFN beta biological responders, biological activity was comparable between the four preparations on day 2 and 3 (+12 and +36 hours post-injection), but it was greater in Betaferon and both Rebif preparations on day 1, 4, and 5. In biological responders treated three times a week, only 82% (59/72) of injections were considered effective, compared with 100% (13/13) of Avonex injections.

CONCLUSION

Our results suggest that an optimal IFN beta regimen is not yet available: Avonex, given once a week, shows lower cumulative biological activity. On the other hand, both Betaferon and Rebif, given three times a week, show 18% biologically ineffective injections and higher risk of developing NAbs, which abolish biological activity.

Persistent neutralizing antibodies abolish the interferon beta bioavailability in MS patients

BACKGROUND

MxA is an antiviral protein exclusively induced by type I interferons (IFN) and some viruses, and MxA gene expression is one of the most appropriate markers for measuring the biologic activity of exogenous IFNbeta.

METHODS

A new quantitative-competitive PCR method was used to quantify MxA mRNA in peripheral blood mononuclear cells of 99 treatment-naïve and 92 IFNbeta-treated patients with MS (22 Avonex, 17 Betaferon, and 53 Rebif-22). Every 3 months, IFNbeta-induced neutralizing antibodies (NAb) were evaluated in sera using a cytopathic effect assay. Three categories of patients were identified: NAb negative (NAb-), persistent NAb positive (NAb+, >or=2 consecutive positive samples), and isolated NAb+ (one positive sample).

RESULTS

Treatment-naïve patients expressed detectable MxA mRNA levels (mean = 36 +/- 32 fg MxA/pg glyceraldehyde-3-phosphate dehydrogenase (GAPDH); range 1 to 160) and an upper normal threshold was established (mean + 3 SD = 132 fg MxA/pg GAPDH). IFNbeta-treated patients exhibited more than 11-fold higher levels (mean = 412 +/- 282 fg MxA/pg GAPDH; range 16 to 1,172). However, 17 patients did not exhibit an increase in MxA mRNA level; 15 of these 17 patients showed a concurrent Nab+ titer. Moreover, 13 were persistent NAb+. Isolated NAb+ patients did not show a decrease in bioavailability of IFNbeta (n = 9; mean = 567 +/- 366 fg MxA/pg GAPDH; range 83 to 1,120). In NAb- patients, bioavailability was comparable among the three different IFNbeta preparations 12 hours after injection.

CONCLUSION

During IFNbeta therapy, the presence of NAb reduced or abolished bioavailability in a relevant percentage of patients. These data could be important for the early detection of patients with MS who are not responsive to IFNbeta therapy.

Dose and Frequency of Administration of Interferon-?? Affect its Efficacy in Multiple Sclerosis

Data reviewed in this article demonstrate that both interferon-beta-1a (IFNbeta-1a) and interferon-beta-1b (IFNbeta-1b) show a dose-response relationship in multiple sclerosis at current clinical doses. Moreover, the efficacy of these therapies is probably dependent on their frequent administration to maintain optimal levels of biological effect. These results differ from the conclusions of a recent review of data comparing two doses of IFNbeta-1a, given intramuscularly once weekly, that showed no difference in efficacy between the two doses. This and other results were interpreted to indicate that the current dose of this product (30microg intramuscularly once weekly) is optimal. However, the data reviewed here indicate that the efficacy of IFNbeta differs depending on the features of the dose regimen, including total dose, route and frequency of administration. Direct comparative data indicate that 44microg given subcutaneously three times weekly is more effective on clinical and magnetic resonance imaging measures, at least up to 48 weeks of therapy, compared with 30microg intramuscularly once weekly; risk-benefit favours 44mug three times weekly over 30mug once weekly.

Comparative assessment of immunomodulating therapies for relapsing-remitting multiple sclerosis

The past decade has seen unprecedented advances in the development of disease-modifying therapies for relapsing-remitting multiple sclerosis (RRMS), a disease that has a worldwide prevalence of two million patients. Four agents with the ability to modulate the immune system are now being widely used for RRMS. Of these, three are forms of interferon (IFN)-beta [IFNbeta-1b and two preparations of IFNbeta-1a (Avonex and Rebif], and one is a polypeptide of four amino acids (glatiramer acetate) with a unique mechanism of action. The administration regimens for the IFNbeta-1a products differ, with Avonex being given as 30 microg intramuscularly once a week and Rebif being given as 22 or 44 microg subcutaneously three times a week. It appears safe to predict that both forms of IFNbeta and glatiramer acetate will remain standard treatments for MS for years to come. However, with four therapeutic options available for RRMS, selecting a single therapy is often difficult and necessitates comparisons of the agents, which can be contentious. All four agents have shown superiority over placebo in pivotal phase III trials. Three recent prospective comparative studies have indicated that IFNbeta-1b, Rebif and glatiramer acetate may be more optimal choices than Avonex for patients with RRMS. In a pharmaceutical environment with an estimated worldwide market of $US2.5 billion annually for RRMS, comparative studies are understandably provocative, but at the same time provide meaningful information to clinicians and patients.

Interferon-beta therapy in multiple sclerosis: evidence for a clinically relevant dose response

There have been considerable advances made recently in the treatment of multiple sclerosis (MS). In particular, interferon (IFN)beta has been demonstrated in several independent, multicentre clinical trials to lower unequivocally the biological activity of this illness. The results of these trials have been remarkably consistent, demonstrating a reduction in both disease activity and cumulative disability, using a combination of clinical and magnetic resonance imaging outcome measures. Nevertheless, the importance of the total weekly IFNbeta dose in the clinical management of individual patients has been controversial. However, there is considerable information available regarding the effect of IFNbeta dose on the various biochemical and clinical markers that are affected by IFNbeta, which is derived both from pre-clinical studies and multicentre clinical trials. On balance, convincing evidence is provided to support the notion that there is a clinically relevant dose-response in the use of IFNbeta to treat patients with relapsing/remitting MS. However, many of the clinical trials of IFNbeta in MS have confounded the potential effects of dose with the possible effects of frequency of IFNbeta administration. As a result, it is possible that the apparent dose-response observed in these clinical trials may be due, in part, to the more frequent dose administration schedule rather than the total weekly dose.

Interferon in oncological practice: review of interferon biology, clinical applications, and toxicities

For the past 40 years, various forms of interferon (IFN) have been evaluated as therapy in a number of malignant and non-malignant diseases. With the advent of gene cloning, large quantities of pure IFN became available for clinical study. This paper reviews the biology, pharmacology, and clinical applications of IFN formulations most commonly used in oncology. It then reviews the most common side effects seen in patients treated with IFN, and makes recommendations for the management of IFN-induced toxicity. The major oncological indications for IFN include melanoma, renal cell carcinoma, AIDS-related Kaposi's sarcoma, follicular lymphoma, hairy cell leukemia, and chronic myelogenous leukemia. Unfortunately, IFN therapy is associated with significant toxicity, which can be divided into constitutional, neuropsychiatric, hematologic, and hepatic effects. These toxicities have a major impact on the patient's quality of life, and on the physician's ability to optimally treat the patient. Careful attention to all aspects of patient care can result in improved tolerability of this difficult but promising therapy.

CONCLUSION

a better understanding of IFN biology, indications, side effect profiles, and toxicity management will aid in optimizing its use in the treatment of patients with cancer.

A prospective, open-label treatment trial to compare the effect of IFN beta-1a (Avonex), IFNbeta-1b (Betaseron), and glatiramer acetate (Copaxone) on the relapse rate in relapsing-remitting multiple sclerosis

A prospective, non-randomized, open-label treatment trial was performed in patients with relapsing-remitting multiple sclerosis (RRMS), with follow up for 12 months. Our primary objective was to prospectively compare the effect of IFNbeta-1a (Avonex), IFNbeta-1b (Betaseron), and glatiramer acetate (GA, Copaxone) on the relapse rate in patients with RRMS. Between August 1996 and September 1999, 156 consecutive patients with clinically definite RRMS with a Kurtzke scale (EDSS) score of 4 or less were followed for 12 months, from the time of initiating therapy or electing to remain untreated. Prior 2-year relapse history and available chart information was carefully reviewed at the time of enrolment. Thirty-three of 156 elected no treatment (mean age 32.5 years; mean EDSS 2.64) at enrolment; 40 elected IFNbeta-1a (mean age 32.4 years; mean EDSS 2.69), 41 IFNbeta-1b (mean age 32.1 years; mean EDSS 2.56), and 42 chose GA (mean age 31.5 years; mean EDSS 2.57). Annual relapse rate based upon the 2 years prior to enrolment was 1.08 in the untreated group, 1.20 in the AV group, 1.21 in the BE group, and 1.10 in the GA group. There were no statistically significant differences among the four groups at enrolment. After 12 months of treatment, patients in the untreated groups had a relapse rate of 0.97, whereas patients in the IFNbeta-1a, IFNbeta-1b, and GA groups had relapse rate of 0.85, 0.61, and 0.62, respectively. Compared to the untreated group, reduction in the relapse rate was statistically significant only in the GA (P=0.003) and IFNbeta-1b (P=0.002) groups, in contrast to the IFNbeta-1a treated patients, who did not show a significant reduction (P=0.309). Compared to the untreated patients, mean EDSS was significantly reduced only in the GA (P=0.001) and IFNbeta-1b (P=0.01), in contrast to IFNbeta-1a treated patients (P=0.51). In this prospective, controlled, open-label, non-randomized 12-month study, treatment with only GA and IFNbeta-1b significantly reduced the relapse rate compared to untreated patients, supporting early treatment in RRMS. Our results are similar to the observations made after 12 months of therapy in phase III studies of IFNbeta-1a, IFNbeta-1b, and GA. Despite some limitations of the study design, the results provide helpful clinical information regarding the relative efficacy of each therapy in mildly affected treatment-naïve RRMS patients.

Interferon-beta1a administration results in a transient increase of serum amyloid A protein and C-reactive protein: comparison with other markers of inflammation

Putative markers of inflammation such as serum beta2-microglobulin and neopterin have been shown to be transiently upregulated following interferon-beta (IFN-beta) administration to multiple sclerosis (MS) patients. However, to date the role of the important inflammatory mediators serum amyloid A protein (SAA) and C-reactive protein (CRP) have not been described. Here we show that SAA but not CRP is elevated in relapsing-remitting MS patients compared to normal healthy individuals, and furthermore that both are transiently upregulated following intramuscular injection with IFN-beta1a (Avonex). This pattern of expression was found to parallel that of beta2-microglobulin and neopterin following injection and was mirrored by a selective activation of peripheral monocytes with respect to upregulation of receptors known to be involved in the inflammatory response (HLA-DR, CD16 and CD86). Injection of saline solution intramuscularly to six healthy control individuals did not produce a similar upregulation of any of the inflammatory markers investigated. Following IFN-beta1a injection, all inflammatory responses were attenuated at week 12 of therapy in comparison to those following the initial injection in a group of follow-up patients. In addition, IFN-beta1a injected on a weekly basis did not produce a sustained modulation of any of the markers investigated in patients treated for 32 weeks.

Pharmacokinetics and pharmacodynamics of IFN-beta 1a in healthy volunteers

The pharmacokinetics of recombinant human interferon-beta1a (IFN-beta1a) (Rebif, Ares-Serono, Geneva, Switzerland) were investigated in healthy volunteers following intravenous (i.v.) administration of increasing single doses of the drug (22 microg/6 million international units [MIU], 44 microg/12 MIU, and 66 microg/18 MIU); i.v., intramuscular (i.m.), and subcutaneous (s.c.) administration of a 66-microg dose; and repeated s.c. administration of four 66-microg doses at 48-h intervals. The disposition of IFN-beta1a followed triexponential decay after i.v. administration (half-lives 3 min, 42 min, and 22 h, respectively). After s.c. and i. m. administration, absorption was the rate-limiting factor in the terminal phase. The median absolute bioavailabilities were 30% and 27%, respectively. The accumulation ratio after repeated s.c. injections was 2.4, and a terminal half-life of 66 h was observed. Intracellular 2-5A synthetase activity and serum neopterin and beta2-microglobulin concentrations increased after all IFN-beta1a injections and remained elevated following every-other-day administration. The local tolerance was good, and the systemic tolerance was satisfactory.

Recombinant human interferon beta in relapsing-remitting multiple sclerosis: a review of the major clinical trials

The beneficial effects of interferon beta (IFN-beta) on disease activity in relapsing-remitting multiple sclerosis (RRMS) have been confirmed in several clinical trials. Three IFN-beta products are currently available and licensed for use in RRMS at different dosages and with different routes of administration. For the prescribing physician, therefore, questions remain about the effect these differences may have on the success of therapy. This paper reviews the four large placebo-controlled clinical trials that have been conducted with IFN-beta in patients with RRMS. The evidence available indicates that optimal results are likely to be achieved with the highest tolerable dosage of IFN-beta. Furthermore, as inflammatory brain lesions in MS have been shown to exhibit more extensive and early axonal damage than previously suspected, early treatment may be advisable in order to delay disease progression in RRMS.

Therapeutic developments in multiple sclerosis

Recently there have been considerable advances made in the treatment of multiple sclerosis. For the first time since its initial clinical description in the 1800s, there are now available several medications which unequivocally exert favourable clinical effects through the lowering of the biological activity of the human illness. The therapeutic efficacy of IFN-beta preparations seems particularly well established in this regard on the basis of five large, independent, trials of this agent. These trials have demonstrated remarkably consistent reductions in both attack rates and disability levels using a combination of clinical and magnetic resonance imaging outcome measures. The therapeutic benefit of glatiramer acetate also has been well established, although there is less available data on this agent than there is for interferon. It is important to recognise, however, that, although these agents represent an important first step in the management of patients with multiple sclerosis, they are only partial therapies. In order to actually cure the illness or even to substantially improve patient outcome we need considerably better agents than we have currently. Nevertheless, it is likely that, with improved knowledge of the role that interferon beta plays in the pathogenesis of multiple sclerosis and with better understanding of the mechanism by which glatiramer acetate exerts its therapeutic effect, greatly improved therapeutic agents will be available in the future. In addition, it seems likely that, in the future (by analogy to the experience in oncology), we will begin utilising combinations of therapies in order to better control the biological activity of this debilitating disease. Such combination therapy will almost certainly include combinations of partially effective agents as well as combinations of these agents with other medications (e.g., the immunosuppressive drugs) which, by themselves, have only been demonstrated to exert marginal clinical benefits on the course of illness. Moreover, it also seems likely that, increasingly, therapeutic strategies that enhance or promote myelin repair will become a major focus of clinical research in this area.

Pharmacodynamic comparison of single doses of IFN-beta1a and IFN-beta1b in healthy volunteers

In a study in 75 volunteers, preparations of interferon-beta1b (IFN-beta1b) and IFN-beta1a were compared in terms of the resulting serum concentrations of three biologic markers, neopterin, human Mx protein, and 2',5' oligoadenylate synthetase. Each preparation was tested at five dose levels, the middle dose being that recommended for use in patients with multiple sclerosis on the basis of large clinical trials. Five randomly chosen volunteers each received a single subcutaneous dose of one of the IFN or of IFN-beta1a given intramuscularly. The amounts of each marker induced were dose related. There were no major differences between the results with the two IFN or in the duration of the changes in the markers after the two routes of injection. The data indicated that 8 million international units (MIU) of IFN-beta1b and 6 MIU of IFN-beta1a had very similar effects. Even after the highest single dose tested, the increase in the biologic markers were not sustained for a full week.

Evidence of interferon beta-1a dose response in relapsing-remitting MS: the OWIMS Study. The Once Weekly Interferon for MS Study Group

OBJECTIVE

To compare efficacy of interferon beta-1a, 22 microg or 44 microg weekly, with placebo in relapsing MS.

BACKGROUND

Uncertainty exists concerning the optimal dose regimen for interferon beta in relapsing-remitting MS. Many patients and physicians prefer the convenience and lesser side effects of an injection given once weekly (qw) as opposed to three times weekly. Pharmacokinetic data and information on biologic markers suggest that this frequency may be suboptimal.

METHODS

Randomized, double-blind study of interferon beta-1a 22 microg, 44 microg, or placebo administered by weekly subcutaneous injection for 48 weeks. Proton density (PD)/T2-weighted and T1-weighted-gadolinium MRI scans during 24 weeks of therapy were analyzed for the number of combined unique (CU) lesions (primary outcome). Biannual PD/T2 scans were analyzed for T2 activity and burden of disease (BOD).

RESULTS

CU lesions at 24 weeks had a median of 0.71/scan with placebo, 0.5/scan with 22 microg (not significant), and 0.33/scan with 44 microg (p = 0.002). T2 new lesion count/scan (mean/median) at 48 weeks was 3.2/1.5 for placebo, 2.4/1.0 for 22 microg (p = 0.03), and 1.5/1.0 for 44 microg (p = 0.0005). BOD at 48 weeks showed a median increase of 5.9% for placebo compared with a decrease of 1.4% in the 44 microg group (p = 0.0058) and 2% in the 22 microg group (p = 0.0018). No clinical variable, apart from steroid use in the 44 microg qw group (p = 0.014), showed significance.

CONCLUSIONS

These data confirm an MRI benefit of interferon beta-1a at low dose in MS, but highlight the limited clinical effect. Taken together with other studies, the data demonstrate a dose-effect relationship for both clinical and MRI variables.

Influence of interferon beta-1a dose frequency on PBMC cytokine secretion and biological effect markers

Interferon-beta regimens for immune-mediated diseases, such as multiple sclerosis (MS), have not been compared regarding their biological effects. In this randomized, parallel-group, placebo-controlled study, cytokine secretion by mitogen-stimulated PBMCs and serum response markers were assessed in volunteers receiving subcutaneous recombinant IFN beta-1a (Rebif, Ares-Serono) 22 microg once a week (QW), 22 microg three times a week, 66 microg QW, or placebo. The production of IL-1beta, IL-6, IFN-gamma, TNF-alpha and TNF-beta markedly decreased during 24-48 h after each injection, with limited dose-dependency and no evidence of tolerance or effect augmentation over 1 month. IL-10 secretion remained unchanged. The increase in serum beta2-microglobulin, neopterin and 2-5A-synthetase was more sustained. Thus, IFN-beta-induced immunomodulation in vivo strongly depends on the administration schedule, the time-integrated effect being 2-3 times greater when a same weekly dose is divided in three injections.

Ribavirin and interferon alfa-2b in chronic hepatitis C: assessment of possible pharmacokinetic and pharmacodynamic interactions

AIMS

The primary objective of this study was to determine whether pharmacokinetic interactions occurred between interferon alpha-2b (IFN) and ribavirin in patients with chronic hepatitis C infections. Additionally this study assessed the single and multiple-dose pharmacokinetics of ribavirin and IFN, and compared the safety, tolerability and antiviral pharmacodynamics of IFN plus ribavirin compared with either drug alone.

METHODS

In this open label parallel group study, patients with chronic hepatitis C were randomized to receive IFN 3 million IU thrice weekly s.c. alone, ribavirin 600 mg twice daily p.o. alone or both drugs in combination over 6 weeks. Single and multiple dose pharmacokinetics and indices of antiviral pharmacodynamics were assessed during weeks 1 and 6, along with safety assessments during the study.

RESULTS

The range of mean ribavirin terminal phase half-lives after single doses was 44-49 h. Comparison of week 1 and week 6 AUC(0,12h) values showed accumulation in plasma of approximately 6-fold. The range of mean washout half-lives after week 6 was 274-298 h, reflecting release of ribavirin from deep compartment stores. The range of single and multiple dose IFN terminal phase half-lives was 5-7 h. IFN demonstrated an increase in bioavailability (approximately 2-fold) upon multiple dose administration. Ribavirin and IFN pharmacokinetic parameters for combined ribavirin and IFN were similar to those during monotherapy with either compound, although the power of this study to detect differences was low. Serum HCV-RNA titers and ALT concentrations were reduced by IFN alone, ribavirin alone reduced ALT concentrations only, and combined IFN plus ribavirin produced numerically greater falls in both measurements than either treatment alone. Serum concentrations of neopterin and activity of 2',5'-oligoadenylate synthetase (2'5'-OAS) were increased by IFN alone and in combination with ribavirin, whereas serum 2'5'-OAS activity was decreased and neopterin concentrations unaltered by ribavirin monotherapy. IFN and ribavirin monotherapy produced characteristic changes in safety laboratory tests (IFN--reductions in white cells, neutrophils and platelets; ribavirin--reduced haemoglobin) and characteristic adverse event profiles (IFN--headache, flu-like symptoms, fatigue, anorexia, nausea, myalgia, and insomnia; ribavirin--headache, fatigue, myalgia, and pruritus). There was no additive effect of combination therapy on safety laboratory tests or reported adverse events. All changes were fully reversible upon treatment cessation.

CONCLUSIONS

There was no evidence of pharmacokinetic interactions between IFN and ribavirin in this study. There were numerical trends indicating that the combination of IFN and ribavirin reduced titers of HCV-RNA to a greater extent than did either treatment alone, and the safety profile of combination therapy was similar to those of both monotherapy treatments.

Comparative study of the pharmacodynamic and pharmacologic effects of Betaseron and AVONEX

The aim of this 1 week study was to compare the biologic effects induced by Betaseron and AVONEX using their approved dose, route, and schedule. Sixteen healthy volunteers were randomly assigned to receive either a single i.m. dose of AVONEX (6 million International Units [MIU]) or, every other day s.c. doses of Betaseron (8 MIU). Common side effects associated with interferon-beta (IFN-beta) treatment and biologic response parameters (neopterin, beta2-microglobulin, interleukin-10 [IL-10], and MxA protein levels in blood) were measured. Ibuprofen was administered to all subjects throughout the study. Fever, chills, and myalgia occurred most frequently and with the greatest severity between 6 and 12 h after the first dose of either IFN-beta. Despite the additional dosing of subjects in the Betaseron group, the incidence, duration, and severity of the side effects were not significantly different from those in the AVONEX group. Biologic response parameters reached similar maximum concentrations in both treatment groups. In the Betaseron group, neopterin and beta2-microglobulin levels remained significantly greater than baseline throughout the 7 day study, whereas those in the AVONEX group were elevated only through day 5. Betaseron treatment significantly increased IL-10 levels above baseline, but AVONEX treatment did not. The overall induction of neopterin, beta2-microglobulin, and IL-10 (as measured by area under the concentration-time curve) was significantly greater in the Betaseron group than the AVONEX group (p = 0.031). The results of this study demonstrate that the approved Betaseron dosing regimen, in combination with ibuprofen use, provided a significantly greater and more consistently elevated biologic response compared with that of AVONEX and did so with a side effects profile comparable to that of once a week AVONEX dosing.

Evidence from transgenic mice that interferon-beta may be involved in the onset of diabetes mellitus

A number of cytokines have been shown to alter the function of pancreatic beta-cells and thus might be involved in the development of type 1 diabetes. Interferon-beta (IFN-beta) expression is induced in epithelial cells by several viruses, and it has been detected in islets of type 1 diabetic patients. Here we show that treatment of isolated mouse islets with this cytokine was able to alter insulin secretion in vitro. To study whether IFN-beta alters beta-cell function in vivo and leads to diabetes, we have developed transgenic mice (C57BL6/SJL) expressing IFN-beta in beta-cells. These mice showed functional alterations in islets and impaired glucose-stimulated insulin secretion. Transgenic animals presented mild hyperglycemia, hypoinsulinemia, hypertriglyceridemia, and altered glucose tolerance test, all features of a prediabetic state. However, they developed overt diabetes, with lymphocytic infiltration of the islets, when treated with low doses of streptozotocin, which did not induce diabetes in control mice. In addition, about 9% of the transgenic mice obtained from the N3 back-cross to outbred albino CD-1 mice spontaneously developed severe hyperglycemia and hypoinsulinemia and showed mononuclear infiltration of the islets. These results suggest that IFN-beta may be involved in the onset of type 1 diabetes when combined with either an additional factor or a susceptible genetic background.

Impaired bioavailability of interferon beta-1a when administered intramuscularly by needle-free injection

Intramuscular (IM) or subcutaneous (SC) drug administration of small molecules and protein has been demonstrated by use of needle-free jet injection methods. One device that achieves needle-free parenteral administration, BIOJECTOR, is commercially available and was evaluated for IM delivery of interferon beta-1a. Recombinant human interferon beta-1a (IFN beta-1a) is a glycosylated protein containing 166 amino acids and has a molecular weight of 22.5 kDa. Needle-free jet injection of IFN beta-1a with the BIOJECTOR was assessed in a human Phase I trial. The study was a randomized, open-label crossover in which 12 healthy subjects each received 60 microg of IFN beta-1a as an IM injection by standard needle administration and by needle-free jet injection. Blood samples for pharmacokinetic (serum activity, PK) and pharmacodynamic (serum neopterin, PD) determinations were collected through 144 hours post-dose. Mean serum antiviral activity AUC values for needle-free and standard needle injection were 218 and 531 U x h/ml, respectively; corresponding C(max) values were 19.7 and 29.0 U/ml. Median T(max) following both treatments was 12 hours. The relative bioavailability of IFN beta-1a, needle-free to standard needle injection, was 41.1% with 90% confidence limits of 24.4% to 69.3%. Mean serum neopterin E(AUC) values for needle-free and standard needle injection were 114 and 325 ng x h/mL, respectively; corresponding E(max) values were 2.3 and 5.6 ng/mL. The ratio of serum neopterin E(AUC), needle-free to standard needle, was 34.9% with 90% confidence limits of 23.4% to 52.1%. Injection site reactions were substantially more frequent following needle-free injection; however, systemic side effects were less frequent. Intramuscular needle-free jet injection and needle-based injection of a 22.5-kDa glycoprotein do not produce equivalent systemic PK or PD responses.

Interferon gamma producing blood lymphocytes are decreased by interferon beta therapy in patients with multiple sclerosis

OBJECTIVE

We studied the individual course of interferon gamma producing blood lymphocyte count (IFGC) of 15 multiple sclerosis patients started on 8 MIU beta interferon administered subcutaneously each other day.

METHODS

Mononuclear blood cells were prepared before treatment and on day 3, 9, 15, as well as after month 1, 2, 3 and 4 of therapy. After stimulation intracellular interferon gamma was detected with monoclonal fluorescent antibodies and measured by flow cytometry. IFGC is given as percentage of all gated lymphocytes.

RESULTS

forty-eight hours after first interferon beta application the mean IFGC dropped significantly from 11.37 to 7.09 (P < 0.05) and to 4.22 within 4 months. Whereas the majority of patients showed a decrease of IFGC from the beginning of therapy, in three of the 15 patients a transient increase of IFGC was seen suggesting a different response to immunomodulatory therapy.

CONCLUSIONS

Interferon gamma producing lymphocyte count might be a useful tool to determine the biological effect of interferon beta therapy in multiple sclerosis patients.

Pharmacokinetics and pharmacodynamics of recombinant human interferon-beta in healthy male volunteers

The pharmacokinetics and pharmacodynamics of recombinant human interferon-beta (rHuIFN-beta 1a) were assessed following administration to 12 healthy male volunteers. Each subject received, in a double-blind, balanced, random-order, crossover sequence, single doses of 6 MIU of rHuIFN-beta 1a (Rebif) i.v., i.m., and s.c. or matching placebo on four occasions separated by washout periods of 1 week. Blood samples were collected at preset times for the measurement of serum IFN-beta levels and of intracellular 2'-5'-oligoadenylate synthetase levels. Blood pressure, sitting heart rate, respiratory rate, oral body temperature, and tolerance were monitored regularly. All administrations of rHuIFN-beta 1a were well tolerated, although about half of the subjects had a flu-like syndrome, as expected. After i.v. bolus injection, the pharmacokinetics of rHuIFN-beta 1a were well described by a classic two-compartment model. Mean total clearance of rHuIFN-beta 1a was about 100 L.h-1. The distribution half-life was 5 min, and the terminal half-life was approximately 5 h. After i.m. or s.c. injection, serum IFN-beta profiles were rather flat, and about one sixth of the administered dose was available systemically. Extent and duration of clinical and biologic effects were independent of the route of administration and of the IFN-beta serum levels. Biologic pharmacodynamic effects persisted even when IFN-beta serum levels had returned to baseline and were still significantly elevated 3 days after a single dose. Because of the independence of the extent and duration of clinical and biologic pharmacodynamic effects from the route of administration and from the IFN-beta serum levels, the s.c route of administration is preferred in indications in which primarily an immunomodulatory action is sought. Predominantly antiviral and antiproliferative activity is enhanced by the i.v. route to provide adequate drug levels at the site of pathology, although its application is limited on practical grounds.

Pharmacodynamics of recombinant IFN-beta during long-term treatment of malignant melanoma

The pharmacodynamics and biologic activities of recombinant human interferon-beta (rHuIFN-beta) derived from chinese hamster ovary (CHO) cells were examined during long-term therapy in 7 melanoma patients. The CHO-derived rHuIFN-beta was given s.c. in a dose of 3 x 10(6) U three times per week for 24 weeks. Serum levels of IFN could not be detected before and 48 h after the s.c. injections. 2'-5'-Oligoadenylate synthetase (2-5 OAS), beta 2-microglobulin, and neopterin levels increased significantly 48 h after application, with a maximum after 96 h. Subsequently, the values decreased and remained only slightly elevated during the long-term therapy. Natural killer (NK) cell activity increased in the first 96 h significantly and fell below pretreatment values after 4 weeks. The decrease of biologic response could not be attributed to the occurrence of anti-IFN-beta antibodies because only 2 of the 7 patients developed neutralizing antibodies after 16 and 24 weeks of treatment, respectively. This trial confirms the biologic potency of CHO-derived rHuIFN-beta. However, the selected parameters demonstrate that immunostimulation is only possible over a short treatment period.

Use of an indirect pharmacodynamic stimulation model of MX protein induction to compare in vivo activity of interferon alfa-2a and a polyethylene glycol-modified derivative in healthy subjects

Interferon alfa-2a was chemically modified by the covalent attachment of a polyethylene glycol (PEG) moiety to enhance its circulating half-life and to reduce its immunogenicity. A comparative evaluation of the pharmacokinetics of the PEG-modified interferon alfa-2a showed a greater than twofold increase in the circulating half-life as a result of this chemical modification. An indirect physiologic response model was developed to characterize the time course of the MX protein response after subcutaneous administration of single ascending doses of either interferon alfa-2a or PEG-interferon alfa-2a in healthy volunteers. Analysis of the pharmacokinetic-pharmacodynamic relationship suggested that the PEG-modified interferon alfa-2a could not be administered less than twice weekly and therefore offered little therapeutic advantage over its unmodified counterpart, which is administered three times weekly. These results were consistent with findings in phase II trials. This study substantiates the usefulness of pharmacodynamic modeling as a tool for the development of dose recommendations and for the early selection of drug candidates in the drug development process.

Interferon-alpha-induced biologic modifications in patients with chronic myelogenous leukemia

Serum neopterin (Np), beta 2-microglobulin (beta 2-M), and 2',5'-adenylate (2',5'A) levels and intracellular 2',5'A and human Mx (Hu-Mx) protein synthesis were measured in 20-24 chronic myeloid leukemia patients before and during 1 year of IFN-alpha treatment and in a further 8-9 patients before and at the end of the first and second treatment weeks only. Univariate analysis showed that IFN-alpha increased Np and 2',5'A serum levels and intracellular concentrations of 2',5'A and Hu-Mx significantly from the end of the first week to month 12 of therapy. The biologic marker profiles were similar in cytogenetic responders and nonresponders, as well as in patients treated with IFN-alpha early (< 12 months from diagnosis) or late (after > 12 months standard chemotherapy). Further, there were no differences in the short-term (first 14 days) or long-term (during 12 month therapy) induction of the biologic markers irrespective of whether IFN-alpha 2a or IFN-alpha 2b was given. Because multivariate analysis revealed no significant interactions between cytogenetic response, time to treatment, and type of IFN-alpha used, increments in intracellular 2',5'A and Hu-Mx protein were similar at all study times for all factor combinations tested. Np levels varied significantly only during the first 14 therapy days; changes in serum 2',5'A were never statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon beta for multiple sclerosis

OBJECTIVE

To introduce readers to the use of a new agent, interferon beta-1b (IFN beta ser), in the treatment of relapsing-remitting multiple sclerosis (RRMS). Therapeutic and economic issues surrounding IFN beta ser are discussed, as are its pharmacology, clinical efficacy, adverse effects, and dosage guidelines.

DATA SOURCES

A MEDLINE search was used to identify pertinent literature, including clinical trials and reviews.

STUDY SELECTIONS

All available trials were reviewed.

DATA EXTRACTION

Since trials evaluating subcutaneously administered interferon beta are sparse, clinical trials evaluating intrathecal IFN beta ser were included, as was toxicology information from the oncology population.

DATA SYNTHESIS

IFN beta ser has recently been approved by the Food and Drug Administration for the treatment of RRMS. Its exact mechanism of action is unknown, but it may downregulate interferon gamma (IFN gamma) production and the IFN gamma-stimulated major histocompatibility complex antigen expression, and/or augment T-suppressor cell function. Primary adverse effects include flu-like symptoms, fever, chills, myalgia, sweating, and injection-site reactions. Clinical efficacy has been investigated in 372 ambulatory patients with RRMS. IFN beta ser treatment resulted in a reduction in the annual exacerbation rate and a greater proportion of exacerbation-free patients. Burden of central nervous system disease was also significantly reduced in treated patients. However, no reductions were detected on the Scripps Neurologic Rating Scale or with confirmed endpoint scores on the Kurtzke Expanded Disability Status Scale. Although many questions remain concerning IFN beta ser's long-term efficacy, its benefits in patients with other types of multiple sclerosis (MS), and its effect on progression of disease and ultimate disability, IFN beta ser is the first treatment modality that has substantially altered the natural course of MS in a controlled clinical trial.

CONCLUSIONS

IFN beta ser is not a cure for MS, but it is well tolerated and patients with RRMS have shown significant improvements in exacerbation rates and burden of central nervous system disease. IFN beta ser should be considered a definite improvement in RRMS treatment, although many therapeutic issues remain unanswered. Additional clinical trials are needed.

Double-blind randomized phase I study on the clinical tolerance and pharmacodynamics of natural and recombinant interferon-beta given intravenously

The clinical tolerance and biological properties of 6 x 10(6) IU of Chinese hamster glycosylated recombinant interferon-beta (rHuIFN-beta) and natural IFN-beta (Frone) given i.v. were compared in 12 healthy volunteers in a randomized cross-over, double-blind trial. All subjects received a single injection of each type of IFN-beta. Both were well tolerated and provoked similar changes in clinical indices. Serum neopterin (Np) values increased significantly from the 24th to 72nd h post-injection of rHuIFN-beta and Frone. beta 2-Microglobulin (beta 2-M) serum levels were statistically above baseline 24-96 h after rHuIFN-beta, and from the 24th to the 120th h with Frone. Both IFNs provoked a rise in intracellular 2',5'-adenylate (2-5A) levels from the 10th to the 48th h, as well as in Hu-Mx synthesis, which was significant from the 10th to the 96th h. Serum levels of 2-5A, interleukin-1 alpha (IL-1 alpha), and interleukin-1 beta (IL-1 beta) remained unchanged. There were no statistical differences in the changes provoked by the two differently derived IFN-beta in any of the biological parameters studied. Overall, the results of this study indicate that rHuIFN-beta and Frone have similar pharmacodynamics.