Status - approved; marketed

Organizations involved:

Schering-Plough Corp. –Manuf.; Tech.; World mark.

Merck & Co., Inc. - Parent

Organon, Inc. – Former

Akzo-Nobel N.V. – R&D; Tech.; Parent; Former

Integrated Genetics, Inc. – R&D; Tech.; Former

Genyzme Corp. – Tech.

Merck Serono S.A. –Tech.

Serono International S.A. – Former

Cross ref.: See the Follicle-stimulating Hormone (FSH) Products entry above.

Description: Follitropin beta or Follistim is a lyophilized (freeze-dried) powder formulation (being phased out) and an aqueous prefilled syringe formulation (Follistim AQ) of recombinant human follicle-stimulating hormone (FSH) glycoprotein expressed by a transformed Chinese hamster ovary (CHO) K1 cell line transfected with a plasmid containing alpha and beta subunit human FSH DNA sequences. The amino acid sequence and tertiary structure of follitropin beta are indistinguishable from that of human FSH. The purification process results in a highly purified preparation with a consistent FSH isoform profile and high specific activity. Follitropin beta has a dimeric structure containing two noncovalently-linked glycoprotein subunits (alpha and beta chains), as does thyroid stimulating hormone and leutenizing hormone). Both the 92-amino acid alpha chain and the 111-amino acid beta chain have complex heterogeneous structures arising from two N-linked oligosaccharide units (glycosylation). Follistim may contain up to 20% of oxidized follitropin beta. See the Follicle Stimulating Hormone (FSH) Products entry above for further structural information.

The rFSH in Follistim, like other mammalian cell expressed glycoproteins, exhibits considerable microheterogeneity. The majority of the rhFSH molecules has an isoelectric point between pH 4.3–5.3, comparable to that of FSH of human pituitary origin, and slightly less acidic than FSH from urinary origin (e.g., Metrodin).

Follistim is standardized for FSH in vivo bioactivity in terms of the First International Reference Preparation for human menopausal gonadotropins (code 70/45), issued by the World Health Organization (WHO) in 1982. As determined by the European Pharmacopoeia versio of this test for FSH in vivo bioactivity and on the basis of its molar extinction coefficient (277 nM), the specific activity of Follistim is 1.066 IU/mg. Intrinsic luteinizing hormone (LH) activity is less than 1 IU per 40,000 IU FSH, and Follistim is considered to contain no LH activity (unlike human-derived FSH products).

Follistim lyophilized powder is packaged in vials (being phased out) containing 75 IU of FSH activity along with a 5 mL vial of Sterile Water for Injection for reconstitution prior to subcutaneous or intramuscular injection. Each Follistim vial also contains as excipients: 25.0 mg sucrose, NF; 7.35 mg sodium citrate dihydrate, USP; 0.10 mg polysorbate 20 (Tween 20), NF; and hydrochloric acid, NF and/or sodium hydroxide, NF to adjust the pH (~7 after reconstitution). Follistim is sold in packages of five vials with five diluent vials. The product is stored at 2-25˚C (36-77˚F; refrigerated) or at room temperature.

In March 2004, approval was granted to Follistim AQ Cartridge, a pre-filled, pre-mixed solution for use in a pen injector device. Cartridges are replacing the lyophilized powder formulation. New 150 and 900 IU cartridges were approved in Feb. 2005. Follistim AQ Cartridges are ready-for-use, prefilled with solution, disposable cartridges containing either follitropin beta in 0.210 mL (833 IU/mL), 350 IU in 0.420 mL (833 IU/mL), 650 IU in 0.780 mL (833 IU/mL) or 975 IU in 1.170 mL (833 IU/mL) of aqueous solution for multiple dose use, with a maximal deliverable dose of either 90, 150 IU, 300 IU, 600 IU or 900 IU, respectively. Excipients used in the cartridges include: benzyl alcohol, NF 10 mg/mL; L-methionine, USP 0.5 mg/mL; polysorbate 20 (Tween 20), NF 0.2 mg/mL; sodium citrate (dihydrate), USP 14.7 mg/mL; sucrose, NF 50 mg/mL; and water for injection, USP. Hydrochloric acid and/or sodium hydroxide are used to adjust the pH to 7.

In Oct. 2005, Follistim AQ became available in 75 IU and 150 IU presentations in single-use 0.5 mL vials in pre-mixed solution, eliminating the need for reconstitution. In Aug. 2005, a new 900 IU Follistim AQ Cartridge became available for use with the Follistim Pen injection device.

Nomenclature: FSH rDNA/Merck & Co. [BIO]; Follistim [TR in U.S.]; Fertavid [TR EU]; Follitropin beta [FDA USAN INN]; follicle-stimulating hormone (human a-subunit reduced), complex with follicle-stimulating hormone (human b-subunit reduced) [CAS]; 146479-72-3 [CAS RN]; Puregon [TR former in Europe]; Org-32489 [SY]; NDC 0052-0306-18; NDC 0052-0306-31 [NDC]

Companies.: Follistim was developed by Organon Teknika Corp., a subsidiary of Akzo-Nobel N.V. The current manufacturing site for recombinant FSH is Organon (Ireland) Ltd., Swords, Co. Dublin, Ireland (now part of Merck).

Follistim lyophilization and finishing was formerly performed at Organon, Inc. facilities in West Orange, NJ. Diluent (Sterile Water for Injection, USP) is manufactured by Luitpold Pharmaceuticals, Inc. In April 2004, Organon announced it was closing its West Orange facility, and was discontinuing the Follistim lyophilized formulation to be replaced fully by the new aqueous prefilled syringe formulation.

Follistim is was originally marketed in the U.S. by Organon, Inc. and internationally by Organon Teknika/Akzo-Nobel affiliates. The product is marketed in Europe as Puregon.

In March 2007, Schering-Plough acquired Organon for ~$11 billion. Organon was merged into Schering-Plough, which now handles manufacturing and marketing.

In March 2009, Merck & Co. acquired Schering-Plough in a deal valued at over $41 billion.

Manufacture: The alpha-subunit of FSH is common to all glycoprotein hormones and is encoded by a single gene, whose complete nucleotide sequence had already been published when Organon started work on recombinant FSH. Because the complete gene was then too large to manipulate, parts of the non-coding sequence (exons) were omitted and a smaller hybrid gene was constructed. The beta-subunits of the glycoprotein hormones are each encoded by different genes, which and determine the biological activity of the individual hormones. However, in the early 1980s, the nucleotide sequence of the human beta-FSH gene had not yet been reported. The published amino acid sequence of the beta-subunit of FSH was used to generate synthetic oligonucleotides for screening of cDNA and genomic libraries, eventually resulting in the isolation of the complete beta-FSH gene.

The development of the manufacturing process also presented challenges, since of the alpha- and beta-subunit must be properly assembled, along with post-translational modifications of the amino acid backbone. Depending on the host-cell type a large repertoire FSH molecules is produced, in which each variant species (glycoform) differs somewhat in the composition of its oligosaccharide side chains. Initially, the sugar residues are attached to the amino acid backbone in the endoplasmic reticulum. Further processing involves trimming by glucosidases and mannosidases, followed by remodelling of the carbohydrates in a complex series of biochemical reactions. These complex reactions can only be performed properly by mammalian cells. The Chinese hamster ovary (CHO) K1 cell line was selected for rFSH expression. This cell line was initiated in 1957 from the ovarian biopsy of an adult hamster and can be readily transfected, with expression of glycosylated rFSH very similar to native human FSH. The CHO cells are cultured in chemically-defined medium.

FDA class: Drug NDA

Approvals: Date = 19970929; first approval, NDA (no. 021273); Indication = treatment of female infertility

Date = 20020226; NDA supplement; Indication = induction of spermatogenesis in men with hypogonadism

Date = 20040323; NDA supplement; Indication = approval of Follistim AQ Cartridge pre-filled, pre-mixed solutions (300 IU/0.525 mL and 600 IU/0.885 mL) for subcutaneous injection using a pen injector device

Date = 20050826; full NDA (NDA 21-273); Indication = approval of AQ formulation

Date = 20050211; NDA supplement; Indication = approval of new dosages of 150 IU and 900 IU per cartridge, and other packaging changes

Date = 20081224l; NDA supplement; Indication = package change

Date = 20100628; NDA supplement; Indication = efficacy supplement with supporting clinical data

indications: [full text of "INDICATIONS AND USAGE” section of U.S. product insert/labeling; 10/2010]:

Follistim AQ is a gonadotropin indicated:

In Women for:

• Induction of ovulation and pregnancy in anovulatory infertile women in whom the cause of infertility is functional and not due to primary ovarian failure.

• Development of multiple follicles in ovulatory women participating in an Assisted Reproductive Technology (ART) program.

In Men for: Induction of spermatogenesis in men with primary and secondary hypogonadotropic hypogonadism (HH) in whom the cause of infertility is not due to primary testicular failure.

indications: [full text of the European Union indications: upon Fertavid approval]:

In the female: Fertavid is indicated for the treatment of female infertility in the following clinical situations: Anovulation (including polycystic ovarian disease, PCOD) in women who have been unresponsive to treatment with clomifene citrate.

Controlled ovarian hyperstimulation to induce the development of multiple follicles in medically assisted reproduction programs (e.g. in vitro fertilisation/embryo transfer (IVF/ET), gamete intra- fallopian transfer (GIFT) and intracytoplasmic sperm injection (ICSI)). In the male: Deficient spermatogenesis due to hypogonadotrophic hypogonadism.

Status: Original FDA approval was granted on Feb. 26, 1997. European approval Union for Puregon was granted on May 3, 1996.

Follistim received original approval in Japan in Aug. 2005 for assisted reproductive technologies (ART). In April 2007, Follistim received approval for use in use in IVF and ICSI procedures. Follistim became the only recombinant fertility hormone to be specifically approved in Japan for both ovulation induction and controlled ovarian stimulation associated with IVF/ICSI.

On Jan. 22, 2009, the CHMP, EMEA, EU, granted MAA approval for Fertavid (under new owner), recognizing that the "quality, safety and efficacy of the Fertavid medicinal product is identical to the up- to-date quality, safety and efficacy profile of Puregon."

Tech. transfer: U.S. Patents listed in the FDA Orange Book as covering aspects of Follistim are U.S. 4,589,402; 5,270,057 (exp. 3/20/2011); 5,767,251 (exp. 6/16/2015) and 5,929,028 (exp. 1/14/2018). U.S. 5,767,251, “Recombinant heterodimeric human fertility hormones, and methods, cells, and vectors and DNA for the production thereof,” assigned to Genzyme Corp. (presumably licensed by Organon/Akzo; originating from R&D conducted by Integrated Genetics, now Genzyme) concerns recombinant fertility hormones (FSH, LH and hCG) with subunits expressed by eukaryotic cells containing DNA for each of the subunits. The FDA Orange Book cites this patent as expiring on June 16, 2015. [Related patents include 4,923,805 and 4,840,896]. U.S. 4,589,402, “Method of in vitro fertilization,” assigned to Serono Labs. (now Merck Serono S.A.; presumably, licensed by Organon/Akzo) concerns methods for in vitro fertilization (inducing ovulation) using hCG and FSH. In Jan. 2007, Merck KGaA acquired Serono, and the new company was renamed Merck Serono S.A. U.S. 5,270,057, “Stabilized gonadotropin containing preparations,” assigned to Akzo N.V., concerns stabilization of lyophilized gonadotropins (LH, TSH, FSH, hCG) using a dicarboxylic acid salt stabilizer, e.g., sodium citrate. The FDA Orange Book lists this patent as expiring March 20, 2011. U.S. 5,929,028,”Liquid gonadotropin containing formulations,” assigned to Akzo Nobel, N.V., concerns stabilization of aqueous formulations of LH, TSH, FSH or hCG using a polycarboxylic acid/salt (sodium citrate),a thioether (methionine), a nonreducing disaccharide, e.g., sucrose, and a non-ionic surfactant.

The U.S. product insert cites U.S. 5,767,251 (in the Orange Book) and 5,929,028 (not in the Orange Book). U.S. 5,929,028,, " Liquid gonadotropin containing formulations," covers aspects of the AQ formulation.

Recombinant FSH-related patent properties held by Akzo Nobel include WO 9519991, “New Composition of Glycoprotein Isoforms Having Follicle Stimulating Activity,” and EP 95907574, same title and filing date.

Trials: The original approvals of Follistim were based on a large prospective, randomized, assessor-blind, multicenter study that compared Follistim and conventional urinary human FSH in IVF. Follistim was more efficacious than urinary FSH as assessed by the number of oocytes retrieved and ongoing pregnancy rate including frozen embryo cycles.

Market: Total worldwide sales were $530 million in 2011; $528 million in 2010; $546 million in 2009, $577 million in 2008; $473 million in 2007; ~$504 million in 2006, and ~$467 in 2005.

The 2007 Average Wholesale Price (AWP) for Follistim AQ is $84.72/75 IU vial; $169.44 /150 IU vial; $338.88/300 IU vial; $677.76/600 IU vial; and $1,106.64/900 IU vial. For comparison, the 2005 AWPs for Follistim AQ were $352.87 for a 300 IU vial and $707.74 for a 600 IU vial.

About 2,250 IU are typically used during each IVF treatment cycle. This would require 30 75-IU vials of Follistim (at the AWP price), costing ~2,654; or 4 600-IU vials of of Follistim AQ, costing ~$2,123.

Unlike other FSH products on the market, the Follistim AQ Cartridge does not require mixing and is delivered through a unique fine-needle, pen injection device. This makes it more convenient for self-administration and easier for physicians to prescribe and instruct patients in its use.