Status - approved; marketed

Organizations involved:

Hoffmann-La Roche Inc. – Manuf.; R&D; Tech.; USA mark.

Hoffmann-La Roche Ltd. – Intl. mark.; Parent

Gilead Sciences, Inc. – USA Mark.

Sloan-Kettering Memorial Cancer Institute – R&D; Tech.

Biogen Idec, Inc. – Tech.

Biogen Corp. – Tech.; Patent dispute; Former

Schering-Plough Corp. – Tech.; Patent Dispute

Genentech, Inc. – R&D; Tech.; USA mark.; Former

Eli Lilly & Co. – Patent dispute

Takeda Chemical Industries, Ltd. – Japan mark.

City of Hope National Medical Center – Tech.; Patent dispute

Cross ref.: See the Interferon Products entry (#793).

Description: Roferon A refers to aqueous formulations of recombinant non-glycoslylated, N-terminal methionine interferon alpha-2a expressed in Escherichia coli (E. coli), with purification including immunoaffinity chromatography using matrix-bound monoclonal antibody specific for interferon alpha-2a. Interferon alfa-2a is produced by the expression of an E. coli start codon (coding for N-methionine; a signal to initiate transcription of mRNA at that point) linked to the DNA sequence for human interferon alpha-2a. The resulting recombinant molecule has the same amino acid sequence as human interferon alpha-2a, except for also having an N-terminal methionine residue; and unlike human interferon alpha-2a, this recombinant interferon alfa-2a is not glycosylated (lacks carbohydrate side chains). Interferon alfa-2a is a type I interferon consisting of 165 amino acid residues with lysine at position 23, a molecular weight of about 19,000 Daltons (~19 kDa), and a molecular formula of C860H1353 N227S9.

Roferon-A is supplied as an injectable solution in single and multiple-use vials and in prefilled multiple-use 0.5 mL syringes for subcutaneous injection. Single Use Injectable Solutions are packaged in 3 million International Unit (MIU) (11.1 µg/mL), 6 MIU (22.2 µg/mL), 9 MIU (33.3 µg/0.9 mL), and 36 MIU (133.3 µg/mL) vials. The 3, 6, and 36 MIU single-use vials also contain 7.21 mg sodium chloride, 0.2 mg polysorbate 80 (Tween 80), 10 mg benzyl alcohol as a preservative, and 0.77 mg ammonium acetate. The 9 MIU vial also contains 6.49 mg sodium chloride, 0.18 mg polysorbate 80, 9 mg benzyl alcohol as a preservative, and 0.69 mg ammonium acetate. Multidose Injectable Solution is packaged in vials for delivery of 9 MIU (33.3 µg/0.9 mL; each 0.9 mL containing 9 MIU) and 18 million IU (66.7 µg/3 mL; each mL containing 6 MIU) interferon alfa-2a. The 9 MIU multidose vial actually contains an average of 13 MIU of Interferon alfa-2a and the 18 MIU multidose vial contains an average of 22.8 MIU, in order to provide the delivery of three and six 0.3 mL (3 MIU) doses, respectively. Note, approvals for multi-use 18 MIU vial and single-use 36 MIU vial were revoked in Sept. 2003. Single Use Prefilled Syringes are available containing 3 MIU, 6 MIU, and 9 MIU in 0.5 mL solution per syringe. Each syringe also contains 3.605 mg sodium chloride, 0.1 mg polysorbate 80, 5 mg benzyl alcohol as a preservative, and 0.385 mg ammonium acetate. The injectable solutions and the prefilled syringes should be stored at 36-46°F (2-8°C; refrigerated).

Nomenclature: Interferon, alfa-2a rDNA [BIO]; Roferon-A [TR]; Interferon alfa-2 [FDA]; interferon alfa-2a [USAN INN BAN]; Interferon Alfa-2 (Genetical Recombination) [JAN]; 76543-88-9 [CAS RN]; 77907-69-8 [CAS RN]; interferon alphaA (human leukocyte protein moiety reduced) [CAS]; 77907-69-8 [CAS RN]; 9008-11-1 [CAS RN for alpha interferons]; interferon alpha-2a [SY]; alpha-2a interferon [SY]; Interferon alpha A [SY]; NSC 377523 [NCI]; rHuIFN-2a [SY]; Ro 22-8181 [SY]; Canferon [TR in Japan]; alfa-2a interferon [SY]; NDC 0004-2007-09; NDC 0004-2010-09; NDC 0004-2011-09; NDC 0004-2012-09; NDC 0004-2015-07; NDC 0004-2015-09; NDC 0004-2016-07; NDC 0004-2016-09; NDC 0004-2017-07; NDC 0004-2017-09 [NDC]

Roferon A, interferon alfa-2a, and other terms are often used ambiguously or imprecisely to refer to the active ingredient and/or the formulated product.

Biological.: Like other interferons, interferon alfa-2a has antiviral, myeloproliferative, and immunomodulatory activities in human cells very similar to that of interferon alpha (the natural complex mixture) from human leukocytes. The biological activities of interferon alpha-2a, like other interferons, are species-restricted, i.e., they occur in a limited number of species other than humans. Thus, most preclinical evaluation of Roferon A involved in vitro studies in human cells and limited in vivo animal studies. Anti-tumor activity has been demonstrated in transplantable mouse (murine) tumor systems.

Potency is determined by comparison of in vitro antiviral activity (using MDBK cells and vesicular stomatitis virus) with that of the international standard preparation of Human Recombinant Alpha 2 (Alpha A) Interferon established by the World Health Organization (WHO).

Companies.: Roferon A was developed and is manufactured and marketed in the U.S. by Hoffmann-La Roche Inc. (Nutley, NJ), FDA CBER est. no. 0136. Interferon alfa-2a is also manufactured at Hoffmann-La Roche Ltd. facilities in Basel, Switzerland. Roferon A marketed in the U.S. by Hoffmann-La Roche Inc.; and is co-promoted in the U.S. for chronic hepatitis C treatment indications: by Gilead Sciences, Inc. Roferon Ais marketed internationally by Hoffmann-La Roche Ltd. and affiliates. It is marketed in Japan by Takeda Chemical Industries, Ltd.

Genentech, Inc., majority owned by Hoffmann-La Roche, was involved in the early development of Roferon-A. Genentech entered into an agreement with Hoffmann-La Roche, Inc. in 1993 under which Genentech marketed Roferon-A in the U.S. through its BioOncology initiative for oncology indications:. However, Roferon A was later returned to Roche.

Manufacture: Roferon A is manufactured by culture of a plasmid-transformed Escherichia coli (E. coli) bacterium containing DNA encoding for expression of human interferon alpha-2a protein along with an E. coli translation start sequence coding for N-terminal methionine. A Master Cell Bank of the plasmid-transformed E. coli used for manufacture has been established. Fermentation is performed in a battery of 400 liter fermentation tanks using a defined nutrient medium containing 5 µg/ml tetracycline hydrochloride (not detectable in the final product). The cells are harvested, concentrated by centrifugation, resuspended, and broken apart/disrupted. E. coli cell wall debris is removed by centrifugation.

The interferon is extracted and purified using immunoaffinity chromatography with a murine monoclonal antibody (selective for interferon alfa-2a) developed by T. Straehelin, Hoffmann-La Roche (see J. Biol. Chem., vol. 256 p. 9750-9754, 1981). [Note, this could well have been updated by now, e.g., using a recombinant antibody]. The crude interferon solution is poured onto a column packed with beads to which the interferon antibodies have been covalently linked. The interferon binds to the antibodies and is later eluted (released) by passing weak acid solution through the column. The interferon is further purified by ion exchange chromatography and size exclusion chromatography. Purified, concentrated product is stored in the frozen state until ready for formulation and packaging.

During manufacture, Roferon A is assessed for identity, strength, quality, purity, and potency. Finished dosage forms are assessed at multiple stages during manufacture by biochemical, chemical, immunological and physical tests, and by quantitative in vitro antiviral bioassay (using MDBK cells and vesicular stomatitis virus). Purified interferon alfa-2a is tested for appearance, color, antiviral activity, SDS polyacrylamide gel electrophoresis, neutralization by an anti-interferon antibody, tryptic digest mapping, DNA content, N-terminal methionine and formyl-methionine, and protein and amino acid composition. Formulated bulk product is tested for sterility. The final product is compounded, sterilized and filled into vials as a liquid dosage form, which is further tested for appearance, color, antiviral activity and protein. Potency is determined by comparison of in vitro antiviral activity with that of the international standard preparation of Human Recombinant Alpha 2 (Alpha A) Interferon established by the World Health Organization (WHO). The consistency of manufacture and the final product has been demonstrated by testing of multiple production lots. Hoffmann-La Roche voluntarily complies with the biosafety guidelines issued by the National Institutes of Health (NIH) Recombinant DNA Advisory Committee.

FDA class: Biologic PLA

CBER class: Biological Response Modifiers

CBER to CDER: Among the products transferred within FDA on June 30, 2003

Approvals: Date = 19860604, first approval; PLA (no. 84-505)/ELA (no. 84-506); Indication = for use in the treatment of hairy cell leukemia in people over 18 year of age or older

Date = 19951019; PLA supplement 94-0381; orphan designation (expired 10/2002); Indication = chronic myelogenous leukemia (CML) in chronic-phase, Philadelphia chromosome-positive patients

Date = 19961200; PLA supplement 94-0782; Indication = chronic hepatitis C diagnosed by HCV antibody and/or a history of exposure to hepatitis C who have compensated liver disease and are 18 years of age or older

Date = 19981121; supplemental PLA 87-0309; orphan designation (expires 11/2005); Indication = Kaposi’s sarcoma, AIDS-associated

Date = 19991117; BLA supplement; Indication = an induction regimen of 6 MIU three times a week for 12 weeks followed by the standard regimen given for an additional 12-36 weeks

Date = 20020815; BLA supplement; Indication = revise the Warnings section of the package insert to include information related to ophthalmologic disorder

Date =20030314; BLA supplement; Indication = approval of Medication Guide

Date = 20030910; BLA supplement; Indication = removal of Kaposi’s sarcoma indication from product labeling; discontinuation of 18 MIU multi-dose vial and 36 MIU single-dose vial

Indications: [full text of "INDICATIONS AND USAGE” section from product insert/label]:

Roferon-A is indicated for the treatment of chronic hepatitis C, hairy cell leukemia and AIDS-related Kaposi’s sarcoma in patients 18 years of age or older. In addition, it is indicated for chronic phase, Philadelphia chromosome (Ph) positive chronic myelogenous leukemia (CML) patients who are minimally pretreated (within 1 year of diagnosis).

FOR PATIENTS WITH CHRONIC HEPATITIS C: Roferon-A is indicated for use in patients with chronic hepatitis C diagnosed by HCV antibody and/or a history of exposure to hepatitis C who have compensated liver disease and are 18 years of age or older. A liver biopsy and a serum test for the presence of antibody to HCV should be performed to establish the diagnosis of chronic hepatitis C. Other causes of hepatitis, including hepatitis B, should be excluded prior to therapy with Roferon-A.

FOR PATIENTS WITH AIDS-RELATED KAPOSI’S SARCOMA: Roferon-A is indicated for the treatment of AIDS-related Kaposi’s sarcoma in a select group of patients. In determining whether a patient should be treated, the physician should assess the likelihood of response based on the clinical manifestations of HIV infection, including prior opportunistic infections, presence of B symptoms, and CD4 count, and the manifestations of Kaposi’s sarcoma requiring treatment (see CLINICAL PHARMACOLOGY).

Status: Manufacturing at Roche facilities in Basel, Switzerland, was approved sometime after original approval. Formulations manufactured at the Nutley and Basel facilities were concluded by FDA to be “biochemically and pharmacokinetically equivalent,” or generic equivalents. In recent years, the Roche Nutley, NJ, facility has been closed.

Roferon A did not receive centralized EU approval, with European approvals country-by-country.

Tech. transfer: The patents and licensing, cross-licensing, and patent disputes concerning Intron A and other interferon alpha products are complex, with the major companies involved and others having both challenged and cross-licensed various U.S. and international patents, and some patent disputes stretching over decades. In summary: Biogen (now Biogen Idec) and Genentech/Roche originally filed competing U.S. patent applications in 1980-1981 covering the composition and manufacture of recombinant forms of alpha interferon, and disputes quickly arose. Roche licensed an early key patent (4,503,035) covering natural, purified forms of interferon alpha; Roche’s partner, Genentech, obtained key recombinant interferon manufacture-related patents; and Schering-Plough licensed key Biogen recombinant interferon alpha patents including coverage for the gene sequence for interferon alfa-2b (Intron A). By the late 1980s, Biogen/Schering-Plough and Genentech/Roche had minimally cross-licensed their respective issued patent properties, allowing continued marketing of their others’ products in the U.S. and other major markets. In mid-1998, Biogen, Inc., Schering-Plough Corp., Hoffmann-La Roche Inc. and Genentech Inc., for the most part, settled their long-running patent disputes concerning interferon products, essentially cross-licensing their respective patent portfolios. The agreement only covered rights in the U.S., and allowed for continued U.S. marketing of Intron A by Schering-Plough and Roferon A by Hoffmann-La Roche, and development of next generation products, e.g., pegylated alpha interferons. Genentech subsequently received another broad recombinant interferon patent, and nonexclusively licensed it to Schering-Plough, Roche and others.

U.S. patent 4,503,035, March 5, 1985, Drs. S. Pestka and M. Rubinstein, Sloan-Kettering Memorial Cancer Institute, assigned to Hoffmann-La Roche, concerns leukocyte cell culture, purification processes, and resulting purified homogeneous interferon species (alpha, beta, gamma, etc.). This patent has been interpreted as covering aspects of all purified, homogenous alpha interferons, whether natural or recombinant. See, “Amino Acid Sequence of a Human Leukocyte Interferon,” S. Pestka, et. al., Proceedings of the National Academy of Sciences, vol. 78 (10), 6186-90, Oct. 1981; “The Human Interferons – From Protein Purification and Sequence to Cloning and Expression in Bacteria: Before, Between, and Beyond,” S. Pestka, Archives of Biochemistry and Biophysics, 221 (1), 1-37, Feb. 15, 1983; and “The Purification and manufacture of Human Interferons,” S. Pestka, Scientific American, vol. 249, no. 2, p. 36-43, Aug. 1983.

A U.S. patent office reexamination of the Sloan/Roche purified alpha interferon patent (4,503,035) was initiated in Dec. 1992 after the Federal Trade Commission (FTC) provided the patent office with documentation allegedly showing that Roche had misrepresented data in the 4,503,035 patent application as a means to control the interferon market. In May 1994, the patent office issued an office action rejecting a number of the patent’s claims. In spring 1996, the patent office confirmed the validity of all 14 patent claims as originally issued, and a number of newer claims were added. This ruling finally ended a patent dispute that had lasted well over a decade, leaving Roche holding a key U.S. (and also foreign equivalents) patent on purified interferons.

U.S. patent 4,530,901, “Recombinant DNA molecules and their use in producing human interferon-like polypeptides,” by C. Weissmann, July 23, 1985, assigned to Biogen (now Biogen Idec), originally licensed exclusively to Schering-Plough (for Intron A), describes recombinant plasmids and methods for expression of mature interferon alpha. Equivalents have issued in many major markets worldwide. The preferred cloning vehicle is the bacterial plasmid pBR322, the preferred restriction endonuclease site is the PstI site, and the preferred host is E. coli HB 101. This is the main patent covering recombinant alpha interferons, and Biogen has asserted that it applies to all recombinant alpha interferons. The equivalent key European patent assigned to Biogen and exclusively licensed to Schering-Plough was upheld in 1993; and Boehringer Ingelheim Pharma, Boehringer Mannheim GmbH, and Bender & Co. lost an appeal of a 1990 decision supporting the Biogen patent.

In 1986, Genentech licensed recombinant alpha interferon manufacturing technology to Hoffmann-La Roche, Inc. (for Roferon A). Genentech patents concerning recombinant methods used for alpha interferon manufacture include U.S. 4,704,362, “Recombinant Cloning Vehicle Microbial Polypeptide Expression,” and U.S. 5,221,619 (issued summer 1994 after considerable delay and disputes). Biogen, Schering and Eli Lilly & Co. challenged 4,704,362 and the 5,221,619 application. Genentech counter-claimed that the two companies were in violation of its earlier patent - Schering-Plough with its interferon alpha (Intron A) and Lilly with its recombinant insulin. As part of its suit, Schering-Plough claimed that no matter what the result, its earlier mutual cross-licensing of interferon patents with Hoffmann-La Roche Inc. (which then owned a controlling interest in Genentech) included licensing of these Genentech patents. In 1995, the U.S. patent office ruled that Genentech/Roche had a earlier invention date than the Biogen patent. In April 1996, Biogen filed suit seeking to reverse this decision, but was not successful.

In mid-1998, Biogen, Inc., Schering-Plough Corp., Hoffmann-La Roche Inc. and Genentech Inc. signed agreements “conclusively” settling their long-running disputes concerning interferon products, essentially cross-licensing their respective patents. This agreement allowed for continued U.S. marketing of Intron A by Schering-Plough and Roferon A by Hoffmann-La Roche, and future marketing of other alpha interferon products, e.g., pegylated interferons. This agreement only covered rights in the U.S. Schering-Plough and Roche also modified their agreement concerning cross-licensing of various alpha interferon patents under which Schering-Plough has rights to the newer Genentech/Roche patent.

In 2002, the patent office issued a new patent (6,482,613, “Microbial production of mature human leukocyte interferons”, which traces its lineage back to application 06/164,986, filed Jul. 1, 1980) to Genentech and Roche. Genentech then concluded royalty-bearing licenses with Schering-Plough, Biogen, and Lilly. U.S. 6,482,613 claims various forms of recombinant “mature leukocyte interferon” (interferon alpha) expressed in E. coli and other bacterial expression systems. This patent, which expires in 2019, essentially covers bacterial-expressed recombinant alpha interferons.

With Roche, Schering-Plough, Genentech, and Biogen Idec now largely having settled their disputes and cross-licensed their patents to each other, generic (biogeneric, biosimilar, biocomparable, follow-on) recombinant alpha interferon products may have a difficult time entering the U.S. market until this patent’s expiration.

As discussed in the Recombinant DNA Product entry (at the beginning of this section), Genentech is appealing a $500+ million award to the City of Hope Medical Center (COH) arising from a 1976 contract and patent licensing dispute involving COH developing basic cloning technology for Genentech. Genentech is appealing to the California State Supreme Court.

Medical: The preferred route of administration for Roferon A is subcutaneous or intramuscular injection. The prefilled syringes are for subcutaneous injection only.

For hairy cell leukemia, patients receive induction doses of Roferon A at 3 million IU/day for 16 to 24 weeks by intramuscular or subcutaneous injection. After induction, the recommended maintenance dose is 3 million IU three times weekly. Patients should be treated for at least six months before determining response and whether to (dis)continue therapy.

For chronic hepatitis C virus (HCV) infection treatment, the recommended dosage is 3 million IU three-times weekly administered by subcutaneous or intramuscular injection for 12 months (48-52 weeks). Normalization of alanine aminotransferase (ALT) liver enzyme levels generally occurs within five weeks after starting therapy in responding patients. Patients who relapse following a full course of treatment may be retreated with 3 or 6 million IU three-times weekly regimen for six to 12 months.

Roferon A use results in detectable neutralizing antibodies in about 25% of patients (in clinical trials). In contrast, Intron A has been shown to have a very low potential (1% in clinical trials) for inducing neutralizing antibodies. Interferon alfa-2a (Roferon A) differs by only one amino acid position from interferon alfa-2b (Intron A).

Newer pegylated forms of interferon, including Pegasys from Roche, and new regimens combining an interferon product with oral ribavirin have increased efficacy for treatment of chronic hepatitis C compared to Roferon A monotherapy and have become the standard-of-care in the U.S. and other developed countries. See the Pegasys, Intron A and PEG-Intron entries below.

Market: Total worldwide sales of Roferon A were $137 million in 2001 (the last year for which Roche has reported sales), and $176 million in 1999. Analysts with PICTET, a Swiss stock brokerage, have reported total Roferon A sales were 171 million Swiss Francs in 2003 ($115.5 million, 4/2005), 180 million in 2002, and 220 million in 2001.

The author’ rough/crude guess for 2006 sales is in the range of $100-$250 million.

The 2007 Average Wholesale Price (AWP) for prefilled syringes is $48.90/3 million IU syringe and $266.94 for six; $97.96/6 million IU, $533.66 for six; $137.64/9 million IU, $651.40 for six (Red Book, 2007). In 2005, the AWP for prefilled syringes was $40.49/3 million IU syringe ($36.72 in 2004) and $242.89 for six ($220.31 in 2004); $80.94/6 million IU ($73.42 in 2004), $485.59 for six ($440.45 in 2004); $113.96/9 million IU (103.37 in 2004), and $683.71 for six.

Schering-Plough Corp. (now Merck) with its recombinant interferon alfa-2b (Intron A) and peginterferon alfa-2b (PEG-Intron) currently holds the commanding market share for interferon products in the U.S. and worldwide. Newer pegylated interferon products, including Pegasys form Roche and PEG-Intron from Schering-Plough, quickly replaced non-pegylated forms, e.g., Roferon A and Intron A, as shown the increasing pegylated interferon sales and decreasing sales of Roferon A (and Intron A). See the entries below for further discussion of the competitive situation with recombinant pegylated alpha interferons.