Not Approved (US) Sexual & Reproductive Health

Follitropin delta

also known as: Rekovelle, FE 999049

Ferring's Rekovelle — a recombinant human FSH produced in a human cell line (PER.C6), dosed via a personalized algorithm based on serum AMH and body weight. Approved in the EU, UK, Canada, Australia, Japan, and China, but received an FDA Complete Response Letter in February 2026 over manufacturing issues; not currently approved in the United States.

A recombinant human FSH manufactured in a human-derived PER.C6 cell line — the first rFSH with human-pattern glycosylation. Approved by the EMA as Rekovelle in December 2016 and subsequently in Canada, Australia, Switzerland, Japan, and China, with a novel individualized dosing algorithm based on serum anti-Müllerian hormone (AMH) and body weight (12 mcg/day fixed dose if AMH <15 pmol/L; 0.10–0.19 mcg/kg/day if AMH ≥15 pmol/L). Ferring received an FDA Complete Response Letter in February 2026 related to the Catalent Indiana manufacturing site; not currently approved in the United States.

Mechanism of action

FSHR agonism equivalent to follitropin alfa/beta. The human-cell-line glycosylation confers modestly increased FSH-receptor affinity and a different bioavailability-to-dose ratio, which underpins the microgram-based (rather than IU-based) dosing convention unique to this product.

Primary uses

  • Controlled ovarian stimulation for IVF/ICSI (ex-US)

Typical dosing

6–12 (individualized) mcg/day daily (subcutaneous (pre-filled pen))

Individualized algorithm: if AMH <15 pmol/L, fixed dose 12 mcg/day for the first cycle; if AMH ≥15 pmol/L, 0.10–0.19 mcg/kg/day (rounded to nearest 0.33 mcg, maximum 12 mcg/day). Subsequent cycles adjusted based on response. Note: doses are expressed in micrograms of protein, not IU, and are not interchangeable IU-for-IU with other rFSH products.

Regulatory status

EMA-approved as Rekovelle (Ferring Pharmaceuticals, December 2016) for controlled ovarian stimulation in women undergoing IVF/ICSI. Approved in the United Kingdom, Canada, Australia, Switzerland, Japan (2023), and China (April 2024). Received an FDA Complete Response Letter in February 2026 citing manufacturing concerns at the Catalent Indiana fill-finish site; not currently approved in the United States. Ferring has stated intent to address the manufacturing findings and re-file.

References

  1. [other] Rekovelle (follitropin delta) Summary of Product Characteristics. European Medicines Agency.
  2. [pubmed] Nyboe Andersen A, et al. "Individualized versus conventional ovarian stimulation for in vitro fertilization: a multicenter, randomized, controlled, assessor-blinded, phase 3 noninferiority trial." Fertil Steril, 2017;107:387-396 (ESTHER-1 pivotal).
  3. [other] FDA Complete Response Letter to Ferring Pharmaceuticals regarding follitropin delta NDA, February 2026 (manufacturing findings at Catalent Indiana).

Related peptides

Follitropin alfa

EMD Serono's Gonal-f — the first recombinant human FSH approved by the FDA (1997). Used for ovulation induction, IVF controlled ovarian stimulation, and male hypogonadotropic hypogonadism fertility induction.

Follitropin beta

Organon/Merck's Follistim AQ (Puregon internationally) — a recombinant human FSH produced independently of follitropin alfa but clinically equivalent; FDA-approved 1997 for ovulation induction and IVF controlled ovarian stimulation.

Urofollitropin

Ferring's Bravelle (and earlier Fertinex) — highly purified urinary-derived FSH used for ovulation induction and IVF controlled ovarian stimulation. FDA-approved 2002; branded Bravelle was withdrawn from the US market in 2015 due to manufacturing/potency concerns but the molecule class remains available via urinary-derived menotropin combination products.

Menotropin

Ferring's Menopur (and earlier Repronex, Humegon) — a urinary-derived FSH/LH combination used for ovulation induction and IVF controlled ovarian stimulation, particularly when LH supplementation is clinically desired.

Corifollitropin alfa

Organon/Merck's Elonva — a recombinant long-acting FSH fusion protein (FSH-CTP) used as a single SC injection to replace the first week of daily FSH in IVF stimulation. Approved by the EMA in 2010; never approved in the United States.

HCG

An FDA-approved fertility and hypogonadism medication commonly discussed in peptide and TRT communities for post-cycle recovery and testicular preservation during testosterone therapy.
Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.