Search

Background: A phase 1b trial was conducted to evaluate the duration of interferon-alpha (IFNα) production after intravesical administration of recombinant adenovirus-mediated interferon α2b (Ad-IFN) formulated with the excipient Syn3. The primary aim was to determine whether a second instillation 3 days after initial treatment produced prolonged urinary IFN production., Methods: The study enrolled seven patients who experienced recurrent non-muscle invasive bladder cancer after bacillus Calmette-Guerin therapy. Each treatment consisted of intravesical instillation of SCH721015 (Syn3) and Ad-IFN at a concentration of 3 × 10 11 particles/mL to a total volume of 75 mL given on days 1 and 4. The patients were followed for 12 weeks, during which the magnitude and duration of gene transfer were determined by urine INFα levels. Drug efficacy was determined by cystoscopy and biopsy, and patients who had no recurrence at 12 weeks were eligible for a second course of treatment., Results: Seven patients were treated with an initial course (instillation on days 1 and 4). Two of the patients had a complete response at 12 weeks and received a second course of treatment. One patient remained without evidence of recurrence after a second course (total 24 weeks). One patient experienced a non-treatment-associated adverse event. Despite a transient rise in IFNα levels, sustained production was not demonstrated., Conclusion: Previously, Ad-IFNα intravesical therapy has shown promising drug efficacy. A prior phase 1 trial with a single instillation compared similarly with the current study, suggesting that a second instillation is not necessary to achieve sufficient urinary IFNα levels.

The safety and toxicokinetics of SCH 721015, an adenovirus encoding the human interferon alpha-2b gene, and Syn3 (SCH 209702), a novel excipient, were assessed in cynomolgus monkeys administered intravesical doses of 2.5 × 10E11 or 1.25 × 10E13 particles SCH 721015 in 25 mg Syn3 or 25 mg Syn3 alone on study days 1 and 91. There was no systemic toxicity. Monkeys dosed with SCH 721015 in Syn3 were positive for SCH 721015-specific DNA in the urine for 2 to 3 days following each dose and had interferon alpha-2b protein in the urine for 1-3 days after a single dose and in fewer animals after a second dose. Intracystic administration was associated with inflammation and focal/multifocal ulceration in the urinary bladder and irritation in the ureters and urethra at necropsy. The physical trauma from catheterization and filling/emptying of the bladder was likely a contributing factor and Syn3 exacerbated the trauma. There was nearly complete resolution of these findings 2 months after the last dose. The trauma to the bladder likely contributed to low, transient systemic exposure to Syn3, SCH 721015 and human interferon protein. The results of this study support the clinical investigation of SCH 721015 in Syn3.

Over the past several years we have obtained considerable evidence indicating that adenoviruses-expressing interferon α (Ad-IFNα) can overcome resistance to the IFNα protein itself. Since cancer cells infected with Ad-IFNα also show high perinuclear cytoplasmic IFNα expression, we were interested in whether endoplasmic reticulum (ER) stress and cleavage of caspase 4 could have a major role in Ad-IFNα-produced cancer cell death. Indeed, procaspase 4 was upregulated and cleaved as early as 12 h after Ad-IFNα infection of the cancer cells, which co-localized with IFNα staining and ER tracker. In contrast, immortalized normal human urothelial cells, although exhibiting similar perinuclear IFNα staining, showed no cleaved caspase 4. Caspase 4 cleavage was not blocked by the caspase 8 specific inhibitor zIETD, indicating that caspase 4 activation was independent of caspase 8 activation. Blocking caspase 4 also inhibited activation of caspase 3 in Ad-IFNα containing cells. Finally, the cleaved form of caspase 4 (p10) was detected in Ad-IFNα-positive cancer cells from the urine of a patient following intravesical Ad-IFNα/Syn3 treatment. Therefore, ER stress and activation of caspase 4 appears to be an important mechanism involved in the direct cancer cell death produced by Ad-IFNα and also occurs in the clinical setting.

Background: Interferon-alpha (IFN) induces complete cytogenetic remission (CCR) in 20-25% CML patients and in a small minority of patients; CCR persists after IFN is stopped. IFN induces CCR in part by increasing cytotoxic T lymphocytes (CTL) specific for PR1, the HLA-A2-restricted 9-mer peptide from proteinase 3 and neutrophil elastase, but it is unknown how CCR persists after IFN is stopped., Principal Findings: We reasoned that PR1-CTL persist and mediate CML-specific immunity in patients that maintain CCR after IFN withdrawal. We found that PR1-CTL were increased in peripheral blood of 7/7 HLA-A2+ patients during unmaintained CCR from 3 to 88 months after IFN withdrawal, as compared to no detectable PR1-CTL in 2/2 IFN-treated CML patients not in CCR. Unprimed PR1-CTL secreted IFNgamma and were predominantly CD45RA+/-CD28+CCR7+CD57-, consistent with functional naïve and central memory (CM) T cells. Similarly, following stimulation, proliferation occurred predominantly in CM PR1-CTL, consistent with long-term immunity sustained by self-renewing CM T cells. PR1-CTL were functionally anergic in one patient 6 months prior to cytogenetic relapse at 26 months after IFN withdrawal, and in three relapsed patients PR1-CTL were undetectable but re-emerged 3-6 months after starting imatinib., Conclusion: These data support the hypothesis that IFN elicits CML-specific CM CTL that may contribute to continuous CCR after IFN withdrawal and suggest a role for T cell immune therapy with or without tyrosine kinase inhibitors as a strategy to prolong CR in CML.

There is a need to improve the treatment of superficial bladder cancer. One area which holds promise is intravesical gene therapy. Recently, studies undertaken by us have shown that marked tumor regression of bladder cancers occurred after two daily intravesical administrations of an adenovirus encoding human interferon alpha (Ad-IFNalpha) using a mouse superficial bladder cancer model in which human bladder tumors are growing. A dose of 1 x 10(11) particles/ml (P/ml) was used along with 1 mg/ml of Syn3, a gene transfer-enhancing agent. Since clinical studies are being planned using this approach, it became critical to determine if one exposure and lower particle number could be equally effective. We report that indeed a single dose of Ad-IFNalpha in Syn3 at doses of 1 x 10(10)-1 x 10(11) P/ml is highly effective in reducing the size of the tumors, whereas 1 x 10(9) P/ml was not. Efficacy was also correlated with the level of IFN produced in the urine after treatment. Based on the results of the present studies, a Phase I trial is being planned for superficial bladder cancer, which will involve a single initial treatment with Ad-IFNalpha/Syn3 and measurement of IFN in the urine over time as an indicator of adequate gene transfer and expression.

Objective: This study was designed to investigate any possible pharmacokinetic interaction between lamivudine and alpha interferon as potential candidates for combination therapy for the treatment of hepatitis B virus (HBV)., Methods: Nineteen healthy male, Caucasian volunteers, aged 20-41 years and weighing 60.5-83.5 kg completed this open, non-randomised study. They each received a single, abdominal, deep s.c. injection of 10 mIU alpha interferon on day 1, followed by a wash-out period of at least 1 week. Subjects then began a 7-day course of lamivudine (100 mg) followed by a further 10-mIU alpha-interferon injection directly after oral lamivudine dosing. Blood and urine samples were taken pre- and post-dose for alpha-interferon and/or lamivudine assay., Results: Lamivudine was safe and well tolerated in all subjects. No adverse events were reported in subjects on lamivudine, whereas 106 adverse events considered attributable to alpha interferon were recorded. Statistical analysis of pharmacokinetic parameters indicated no significant effect of lamivudine on alpha-interferon pharmacokinetics. There was a small statistically significant reduction (approximately 10%) in the area under the lamivudine concentration time curve on co-administration with alpha interferon and a concomitant increase in clearance, which is not considered clinically relevant., Conclusions: Alpha interferon and lamivudine can be co-administered with no requirement for dose modification, as there was no clinically significant difference in the pharmacokinetics of either drug.

Purpose: We determined and compared the presence and frequency of interferon-alpha 2b receptors in urothelial neoplasms and normal urothelium, since the biological activity of interferons becomes apparent only after they bind to specific receptors., Materials and Methods: With our method detection of interferon-alpha 2b receptors required a large number of cells, that is more than 1 x 10(6) cells per ml. We studied 14 patients with relatively large tumors of all stages and grades. Three patients had grade I, 4 grade II and 7 grade III disease. As controls we used biopsies of normal urothelium from 14 patients who underwent transvesical prostatectomy. Interferon-alpha 2b receptors were detected quantitatively through the binding of radiolabeled 125iodine human recombinant interferon-alpha 2b in normal and malignant urothelial tissue samples. The interferon-alpha 2b receptors are expressed as receptor sites per cell, and the results were evaluated with Scatchard analysis., Results: The number of interferon-alpha 2b receptor sites per cell ranged from 43 to 100 (mean plus or minus standard deviation 62 +/- 18) in normal urothelium and from 110 to 210 (mean 174 +/- 25) in malignant epithelium. This difference was statistically significant (p < 0.001), Student's t test 13.75). The difference in the number of interferon-alpha 2b receptors in grades I plus II and grade III tumors is suggestive but not statistically significant (p < 0.10, Student's t test 2.075). High grade tumors expressed greater numbers of interferon-alpha 2b receptors than low grade tumors., Conclusions: The method used needs refining so that it will require fewer cells to determine interferon-alpha 2b receptors. Interferon-alpha 2b receptors are detected in bladder urothelium and are abundant in malignant tissue with increasing frequency as tumor grade increases. If we can establish, in the future, a correlation of the number of interferon-alpha 2b receptors with the potential response of patients to intravesical instillation therapy with interferon, we might have an important prognostic method for selecting subgroups of patients with transitional cell carcinomas who will benefit from interferon-alpha 2b instillation.