ALFERON® N INJECTION
INTERFERON ALFA-N3 (HUMAN LEUKOCYTE DERIVED)

The First Natural-Source
Multi-Subspecies Alpha Interferon


A significant advance in the treatment of refractory or recurrent condylomata acuminata (genital warts)*


*Intralesional injection in patients 18 years of age or older.


Distributed by:
HEMISPHERX BIOPHARMA, Inc.
Philadelphia, PA 19103
www.hemispherx.net

Table Of Contents

Introduction

Description

Biology of Interferons

Clinical Efficacy

Efficacy in Patients with Condylomata Acuminata

• Double-blind Study

• Open-label study

Efficacy in Patients with Cancer

Safety

Adverse Reactions in Patients with Condylomata Acuminata

• Clinical signs and symptoms

• Application site reactions

• Clinical laboratory abnormalities

• Clinical immunologic findings

Adverse Reactions in Patients with Cancer

• Clinical signs and symptoms

• Clinical laboratory abnormalities

Conclusion

References

Introduction

ALFERON® N Injection, Interferon alfa n-3 (Human Leukocyte Derived) is the first natural alfa interferon product made available to physicians in the United States.

Interferons are naturally occurring, hormonelike proteins with antiviral, antiproliferative, and immune-enhancing properties. They are produced by the body at low levels in response to viral infection or to other inducers. At least 18 different protein subspecies of alfa interferon are recognized.¹ Unlike recombinant alfa interferon products which contain a single subspecies of alfa interferon, ALFERON® N Injection, derived from human leukocytes, contains at least 14 alpha interferon molecules.

ALFERON® N Injection is indicated for the intralesional treatment of refractory or recurrent external condylomata acuminata (genital warts) in patients 18 years of age or older. Genital warts, one of the most widespread sexually transmitted diseases in the United States, are believed to be caused by infection with human papilloma viruses (HPV), particularly types 6 and 11. Some strains of HPV (types 16 and 18) have been associated with cervical dysplasia, and cervical and anal carcinomas.

Traditional therapy for genital warts has been limited to ablative procedures, including cryosurgery or laser therapy, or to caustic agents, such as topical podophyllin or trichloroacetic acid. These procedures are often painful, produce ulcerations and scarring, and are frequently associated with recurrence. Recombinant interferon alfa-2b administered by intralesional injection has been approved for the treatment of genital warts.

Back To Top

Description

ALFERON® N Injection, Interferon alfa-n3 (Human Leukocyte Derived), is a sterile aqueous formulation of purified, natural, human interferon alpha proteins for use by injection. ALFERON® N Injection consists of interferon alpha proteins comprising approximately 166 amino acids and ranging in molecular weight from 16,000 to 27,000 daltons. The specific activity of interferon alfa-n3 is approximately equal to, or greater than, 2 x 108 IV / mg of protein.

ALFERON® N Injection is manufactured from pooled units of human leukocytes, which have been induced by incomplete infection with an avian virus (Sendai virus) to produce interferon alfa-n3. The manufacturing process includes immunoaffinity chromatography with a murine monoclonal antibody, acidification (pH 2) for five days at 4 °C, and gel filtration chromatography.

The source leukocytes used in the manufacture of ALFERON® N Injection have been screened for infectious agents in accordance with federal regulations. The manufacturing process also contains steps which have been shown to inactivate and/ or clear viruses. There has been no evidence of infection transmitted to patients treated in clinical trials. Like the recombinant alpha interferon products, ALFERON® N Injection contains human albumin. The laboratory and clinical data obtained support the conclusion that ALFERON® N Injection is equivalent to other products derived from or containing elements of human blood or plasma, such as immunoglobulin and albumin, which are free of risk from transmission of infectious agents.

ALFERON® N Injection is available in an injectable solution containing 5 million IV ALFERON® N Injection per vial for intralesional injection, Each milliliter contains 5 million IV of interferon alfa-n3, 3.3 mg phenol, and 1 mg human albumin in a pH 7.4 phosphate-buffered saline solution (8.0 mg sodium chloride, 1.74 mg sodium phosphate dibasic, 0.20 mg potassium phosphate monobasic, and 0.20 mg potassium chloride).

Back To Top

Biology of Interferons

Interferons are naturally occurring proteins with antiviral, antiproliferative, and immune-enhancing properties. They are produced and secreted in response to viral infections and to a variety of other synthetic and biological inducers. Three major families of interferons have been identified: alpha, beta, and gamma. The interferon alpha family contains at least 18 different molecular species. Their molecular weights range from 16,000 to 27,000 daltons.

Interferons bind to specific membrane receptors on cell surfaces. Interferon alfa-n3 has been shown to bind to the same receptors as interferon alfa-2b. The receptors have a high degree of selectivity for the binding of human interferon. This selectivity correlates with the high species specificity found in laboratory studies.

Binding of interferon to membrane receptors initiates a series of events including induction of protein synthesis. These actions are followed by a variety of cellular responses that include inhibition of virus replication and suppression of cell proliferation. Immunomodulation, involving enhancement of phagocytosis by macrophages, augmentation of the cytotoxicity of lymphocytes, and enhancement of human leukocyte antigen expression, occurs in response to exposure to interferons. One or more of these activities may contribute to the therapeutic effect of interferon.

Back To Top

Clinical Efficacy

Efficacy in Patients with Condylomata Acuminata

Double-blind study. Condylomata acuminata (genital warts) are associated with infections of human papilloma viruses (HPV). Since interferons show antiviral and antiproliferative activities, a clinical study was conducted to evaluate the efficacy and safety of ALFERON® N Injection in the treatment of genital warts.^(2-5)

A total of 189 male and female patients entered this multicenter, randomized, double-blind, placebo-controlled trial. Patients had a mean of five genital warts (range, 2 to 14); all warts were treated. Warts were generally large with a mean total wart area of 83 mm2 per patient. Eighty-eight percent of the patients had recalcitrant warts, i.e., warts that were refractory to therapy or that recurred after prior therapy. One hundred four patients were administered ALFERON® N Injection intralesionally at the base of each wart. The mean dose of ALFERON® N Injection was 225,000 IV per wart given two times a week for up to eight weeks. Eighty-five patients received placebo.

In the 156 patients evaluable for efficacy, ALFERON® N Injection was significantly more effective than placebo in resolving treated warts (Table 1). ALFERON® N Injection produced complete or partial resolution of warts in 80% of the treated patients compared with 44% of the patients receiving placebo (P < 0.001).

*Complete and partial resolution data show a statistically significant (P<O.OO1) difference from placebo.

Of the 762 evaluable warts treated in this trial, 73% (297 of 407) of the ALFERON® N Injection-treated warts completely resolved compared with 35% (125 of 355) of the placebo-treated warts (P < 0.0001). ALFERON® N Injection was significantly more effective than placebo in reducing wart size over the course of the study as indicated by total wart volume per patient (P < 0.0001) (Figure 1). ALFERON® N Injection was effective in treating lesions of all sizes and locations; there were no differences in resolution rates for perianal, penile, or vulvar lesions.

There was no significant difference in resolution rates between patients who had received prior therapy for genital warts and patients who had no prior therapy. Among patients with recalcitrant warts, i.e., warts that were refractory to prior therapy or that recurred after prior therapy, 82% (58 of 71) of the evaluable patients had complete or partial resolution of warts after intralesional administration of ALFERON® N Injection compared with 43 % (29 of 67) of the placebo-treated patients (P < 0.001). Fifty-four percent (38 of 71) of the evaluable ALFERON® N Injection-treated patients had complete resolution of warts compared with 18% (12 of 67) of the placebo-treated patients (P<O.OO1).

Patients with primary warts, i.e., patients never receiving prior treatment, responded similarly to patients with recalcitrant warts. Seventy percent (7 of l0) of the evaluable patients with primary warts receiving ALFERON® N Injection had complete or partial resolution of warts compared with 50% (4 of 8) of the patients receiving placebo. Because the number of patients with primary warts was small, the difference between treatments was not statistically significant. When the resolution rates were compared by numbers of warts, however, the difference was significant. Seventy-five percent (33 of 44) of the ALFERON® N Injection-treated primary warts resolved completely compared with 39% (11 of 28) of the placebo-treated primary warts (P=O.O03).

Of the ALFERON® N Injection-treated patients with complete resolution of warts, half showed complete resolution of warts by the end of the treatment period, while half showed complete resolution during the three months after the end of treatment (Figure 2). Patients with complete resolution of warts were followed for a median of 48 weeks. Overall, 76% (31 of 41) of ALFERON® N Injection-treated patients who achieved complete resolution of warts remained clear of all treated lesions during follow-up compared with 79% (11 of 14) of placebo treated patients.

An evaluation of patient preference for wart therapy showed that 58% of the patients treated with ALFERON® N Injection believed that ALFERON® N Injection therapy was better than their prior treatments. Seventy-nine percent of the patients treated with ALFERON® N Injection would repeat ALFERON® N Injection therapy if their warts recurred. These data indicate that a minority of patients who had experienced ablative wart therapies found intralesional injections to be acceptable.

In summary, the results of this double-blind clinical trial show that ALFERON® N Injection administered intralesionally was highly effective in the treatment of condylomata acuminata. Treatment with ALFERON® N Injection promoted complete resolution of genital warts and significantly reduced wart number and volume. Clearance of genital warts was maintained after treatment was discontinued. Patients preferred ALFERON® N Injection over their prior therapies.

Open-label study. Resolution rates of genital warts in an open-label study, in which ALFERON® N Injection was administered once weekly for up to 16 weeks, were similar to those observed in the double-blind trial (A. Friedman-Kien and L. Eron, unpublished data, July 1987). Of the 28 ALFERON® N Injection-treated patients evaluable for efficacy, 89% had complete or partial resolution of warts, while 46% had complete resolution. Seventy-seven percent of the 154 warts treated resolved completely.

Back To Top

Efficacy in Patients with Cancer
The efficacy of ALFERON® N Injection has not been established in hairy cell leukemia, Kaposi's sarcoma, or other tumors.

Back To Top

Safety
Safety was evaluated in 202 patients with condylomata acuminata given ALFERON® N Injection by intralesional administration and in 31 patients with cancer given ALFERON® N Injection intramuscularly. The doses of ALFERON® N Injection administered in these studies are given in Table 2.

Back To Top

Adverse Reactions in Patients with Condylomata Acuminata

Clinical signs and symptoms. "Flulike" adverse reactions, consisting primarily of myalgias, fever, and/or headache, were the most frequently reported adverse reactions in patients with genital warts treated intralesionally with ALFERON® N Injection in the double-blind study (Table 3).2-5 "Flulike" adverse reactions were reported by 30% of the patients after the first injection. These adverse reactions decreased in frequency with repeated dosing; after three to four weeks of ALFERON® N Injection therapy (six to eight treatment sessions), the incidences of "flulike" symptoms in treatment and control groups were similar. "Flulike" adverse reactions were relieved by the administration of acetaminophen.

*Patients reporting an adverse reaction at least once during the course of therapy.

Most of the reported adverse reactions were mild or moderate. Severe systemic adverse reactions were reported by 18% of the patients receiving ALFERON® N Injection compared with 13% of the placebo-treated patients. The difference between treatments was not statistically significant. Most of the severe systemic adverse reactions were "flulike"; other severe systemic adverse reactions included back pain, insomnia, and sensitivity to allergens.

The frequency and type of adverse reactions reported in patients given ALFERON® N Injection in the open-label study were similar to those observed in the double-blind trial (A. Friedman-Kien and L. Eron, unpublished data, July 1987).

Back To Top

• Application site reactions. Significantly fewer application site reactions, such as itching and pain, were observed in patients treated with ALFERON® N Injection in the double-blind trial than in placebotreated patients (12% versus 26%) (P=O.O2). No severe application site reactions were reported by ALFERON® N Injection-treated patients; 7% of placebo-treated patients reported severe reactions.
  
• Clinical laboratory abnormalities. Abnormalities in laboratory test values were seen with statistically equivalent frequencies in both ALFERON® N Injection and placebo-treated groups in the double-blind trial. None of these abnormalities was considered clinically significant; in patients receiving ALFERON® N Injection, they involved increases of only one WHO grade. There was an 11 % decrease in WBC count in ALFERON® N Injection-treated patients compared with a 4 % decrease in patients receiving placebo. The difference was not statistically significant.
  
• Clinical immunologic findings. One hundred five patients treated with ALFERON® N Injection during clinical trials were tested for the presence of anti-interferon antibodies using three different assays. No antibodies to interferon alfa-n3 were detected in any patient.

Back To Top

Since ALFERON® N Injection, like the recombinant alpha interferon products, is manufactured using a murine monoclonal antibody in one purification procedure, there is a possibility that patients treated with ALFERON® N Injection may develop hypersensitivity to mouse proteins; however, none of the patients receiving ALFERON® N Injection during clinical trials developed antibodies or hypersensitivity to mouse proteins.

The initial manufacturing stage of ALFERON® N Injection uses Sendai virus grown in chicken eggs as the specific interferon alfa-n3 inducer. Although no egg protein has been detected in ALFERON® N Injection, a possibility exists that patients treated with ALFERON® N Injection may develop hypersensitivity to egg protein.

Adverse Reactions in Patients with Cancer

• Clinical signs and symptoms. Adverse reactions reported at least once during the course of treatment in 31 patients with cancer given a maximum of ten intramuscular injections of 3, 9, or 15 million IV of ALFERON® N Injection are presented in Table 4 (R. Bukowski, unpublished data, June 1984; 1. Concannon, unpublished data, May 1984). The incidence of adverse reactions in ALFERON® N Injection-treated patients was not dose related.

Back To Top

• Clinical laboratory abnormalities. Patients with cancer who experienced an abnormal laboratory test value which was clinically significant (values which changed from WHO grades 0, 1, or 2 at baseline to WHO grades 3 or 4 during or after treatment) at least once during the study are given in Table 5.

Back To Top

Conclusion

The studies reported above demonstrate the efficacy and safety of intralesional ALFERON® N Injection in the treatment of condylomata acuminata, especially in patients with refractory or recurring lesions. The antiviral, antiproliferative, and immune-enhancing effects of ALFERON® N Injection offer a specific treatment modality directed at the cause of genital warts compared with traditional ablative treatments. These traditional ablative procedures, such as cryosurgery, laser therapy, and topical podophyllin or trichloroacetic acid, are often painful, produce ulcerations and scarring, and are frequently associated with recurrence.

Adverse reactions with ALFERON® N Injection were limited primarily to "flulike" symptoms, including myalgias, fever, and/or headache. These adverse reactions decreased in frequency with repeated dosing; after three to four weeks of treatment, the incidence was comparable to placebo. No anti-interferon antibodies were detected in any patient treated during clinical trials.

Back To Top

References

1. Pestka S: Methods Enzymol1986;1l9:3-14. 2. Friedman-Kien AE, Eron LJ, Conant M, et a1: lAMA 1988;259(4):533-538. 3. Friedman-Kien AE, P1asseTF, Cremin P, et a1: in Howley PM, BrokerTR (eds): Papillomaviruses: MolecularandClinicalAspects. New York, A1anRLiss, Inc, 1985, pp217-233. 4. Geffen JR, Klein RH, Friedman-Kien AE: 1 Infect Dis 1984;150(4):612-615. 5. Data on file, Interferon Sciences, Inc., New Brunswick, New Jersey, 1988.