Follitropin delta
Follicle-stimulating hormone made in a human cell line and dosed from AMH and body weight
Follitropin delta is recombinant human FSH produced in a human-derived cell line (PER.C6), which gives it sialic acid sugar chains like those of natural human FSH. It is used for ovarian stimulation in IVF at a dose calculated in advance from the woman's AMH level and body weight; it is marketed in Japan as Rekovelle and has no US approval.
What is it?
Most recombinant FSH starts at a standard dose that the clinic adjusts as follicles grow. Follitropin delta's regimen fixes the daily dose before stimulation: women with an AMH below 15 pmol/L get 12 µg, and those with higher AMH a smaller dose per kilogram, with the aim of fewer cases of ovarian hyperstimulation syndrome (OHSS).
In the pivotal ESTHER-1 trial, individualised dosing matched follitropin alfa on live births (29.8% against 30.7%) with fewer excessive responses and fewer steps taken to prevent OHSS (2.3% against 4.5%). The Asian trial found fewer eggs but a higher live birth rate, the Japanese trial halved moderate or severe OHSS, and a 2024 meta-analysis judged the differences small, on low-certainty evidence.
Pooling individual patients from three trials sharpens the picture: the benefit sits in women with higher AMH, whose live birth odds rose and OHSS risk fell by about 70% on a lower total dose, while women with low AMH did about the same as on conventional FSH. When it was instead dosed conventionally, in ADAPT-1, it behaved like follitropin alfa.
Outcomes over a year depend on how many eggs are retrieved and on age: in a pooled analysis of 1,746 patients, cumulative live birth was about 51%, rising past 60% with more than 15 oocytes and falling to 36% at 38 and over. In routine Nordic practice most women got the algorithm dose and about half hit the targeted 8 to 14 oocytes. It is marketed in Japan as Rekovelle, is used in routine care in the Nordic countries and Switzerland, and is not approved in the US.
Mechanism of Action
Follitropin delta is recombinant human FSH made in a human cell line, dosed in micrograms by an algorithm based on AMH and body weight.
FSH receptor
Stimulates growth of multiple ovarian follicles for egg retrieval in IVF.
Fixed by algorithm
The daily dose is set before stimulation from AMH and weight rather than adjusted cycle by cycle.
Fewer over-responses
In women with higher AMH, individualised dosing reduced OHSS and preventive interventions.
Published Research
Trials read from their PubMed abstracts, with one meta-analysis; follitropin delta has no US label.
1,009 women in four Asian countries
Against conventional follitropin alfa, individualised follitropin delta retrieved fewer oocytes (10.0 against 12.4) but gave a non-inferior ongoing pregnancy rate, a higher live birth rate and less early OHSS or preventive intervention.
347 women in Japan
Against follitropin beta 150 IU/day, oocyte numbers were non-inferior (9.3 against 10.5), and OHSS fell from 19.8% to 11.2% overall and from 14.1% to 7.1% for moderate or severe cases.
Potential low responders
Pooling five randomised trials, women with AMH below 9 pmol/L on algorithm-dosed follitropin delta yielded fewer eggs (6.3 against 10.8) but similar ongoing pregnancy (29.2% against 31.8%) and live birth rates to women with higher AMH.
RITA: against placebo
In placebo-controlled trials, cumulative ongoing pregnancy was 64.0% on follitropin delta in women under 35 and 43.9% at 35 and over, against none on placebo; cumulative live birth was 62.5% and 42.4%.
ADAPT-1: conventional dosing
Given in a conventional, adjustable way rather than by algorithm, follitropin delta retrieved the same mean 9.9 oocytes as follitropin alfa in 300 women, with similar clinical pregnancy (31.6% against 31.0%) and early OHSS (2.5% against 3.0%).
BEYOND: agonist or antagonist protocol
In 437 women on algorithm-dosed follitropin delta, a GnRH agonist protocol retrieved 1.3 more oocytes than an antagonist protocol (11.1 against 9.6), with the gap largest in younger women with high ovarian reserve.
NORSOS: routine Nordic practice
In 199 women in Nordic and Swiss clinics, 84.9% were prescribed the algorithm dose (mean 10.2 µg); 47.9% achieved the targeted 8 to 14 oocytes and 28.4% had more than 15.
One-year cumulative live birth
Pooling four trials and 1,746 patients, cumulative live birth was 51.4%, rising with oocyte number to a plateau around 21 to 25 and falling with age (57.1% under 35, 35.8% at 38 and over).
Meta-analysis of three trials
Across 2,682 participants, follitropin delta made little to no difference to live births (risk ratio 1.12) or moderate or severe OHSS (0.78) compared with follitropin alfa or beta; certainty was low.
Single doses in healthy women
In 24 healthy Chinese women given 12, 18 or 24 µg once, exposure rose in proportion to dose, levels peaked at a median of 24 hours and the half-life was 50.5 to 60.9 hours; adverse events were mild apart from one moderate urticaria.
Individual patient data meta-analysis
Across three trials and 2,685 women, individualised dosing raised live birth in women with AMH of 15 pmol/L or more (odds ratio 1.64) and cut OHSS or preventive interventions (0.27), using less gonadotropin; in lower-AMH women live birth was similar.
Dosing Data
It is not approved in the US. Where it is used, the dose is set by an algorithm: 12 µg a day if AMH is below 15 pmol/L, otherwise a lower dose per kilogram that falls as AMH rises.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Side Effects & Contraindications
Reported Side Effects
From the trials.
Contraindications & Cautions
No US label exists.
Legal Status
Not approved in the US; marketed in Japan.
Frequently Asked Questions
?Is follitropin delta available in the US?
No. Drugs@FDA lists no application for it; follitropin alfa and beta are the recombinant FSH products this site covers as US-approved.
?How is the dose chosen?
From serum AMH and body weight before stimulation: 12 µg a day below an AMH of 15 pmol/L, otherwise 0.10 to 0.19 µg per kilogram (6 to 12 µg in the Japanese trial).
?Is it better than other FSH?
A 2024 meta-analysis found little to no difference in live births or moderate to severe OHSS against follitropin alfa or beta, on low-certainty evidence.
?Does it work better than placebo?
Yes, clearly. In the RITA trials, cumulative ongoing pregnancy was 64.0% in women under 35 and 43.9% at 35 and over on follitropin delta, against none on placebo.
?Who benefits most from algorithm dosing?
Women with higher AMH, 15 pmol/L or more. In pooled data from three trials they had higher live birth odds and about 70% lower odds of OHSS or preventive steps on a lower total dose. Women with lower AMH did about as well as on conventional FSH.
?Does the protocol matter?
Somewhat. In the BEYOND trial a GnRH agonist protocol retrieved about 1.3 more eggs than an antagonist protocol, most in younger women with high ovarian reserve.
References
- [clinical-trial] Qiao J, et al. "A randomised controlled trial to clinically validate follitropin delta in its individualised dosing regimen for ovarian stimulation in Asian IVF/ICSI patients." Hum Reprod, 2021;36(9):2452-2462. PMID: 34179971.
- [clinical-trial] Ishihara O, et al. "Individualized follitropin delta dosing reduces OHSS risk in Japanese IVF/ICSI patients: a randomized controlled trial." Reprod Biomed Online, 2021;42(5):909-918. PMID: 33722477.
- [review] Komiya S, et al. "Efficacy and safety of follitropin delta versus follitropin alpha/beta in infertility treatment: A systematic review and meta-analysis." Reprod Med Biol, 2024;23(1):e12573. PMID: 38528991.
- [clinical-trial] Shao F, et al. "Pharmacokinetics and Safety of Follitropin Delta in Gonadotropin Down-Regulated Healthy Chinese Women." Clin Drug Investig, 2023;43(1):37-44. PMID: 36478528.
- [clinical-trial] 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(2):387-396.e4. PMID: 27912901.
- [other] EMA medicines dataset: Rekovelle (follitropin delta), authorised December 12, 2016. Read October 5, 2026.
- [pubmed] Lobo R, et al. "Efficacy of follitropin delta in potential low responders: a pooled analysis of individual patient data from five randomized controlled trials." Front Endocrinol (Lausanne), 2026;17:1880515. PMID: 42761056.
- [pubmed] Scheiber MD, et al. "Ovarian stimulation with follitropin delta is safe and effective: results from the RITA randomized, double-blind, placebo-controlled trials." Fertil Steril, 2026;125(1):54-63. PMID: 40714031.
- [pubmed] Bernabeu A, et al. "Ovarian stimulation with follitropin delta for in vitro fertilization: a multicentre, randomized, assessor-blind comparison with follitropin alfa using conventional dosing regimens (ADAPT-1 trial)." Hum Reprod, 2025;40(9):1660-1670. PMID: 40633120.
- [pubmed] Lobo R, et al. "BEYOND: a randomized controlled trial comparing efficacy and safety of individualized follitropin delta dosing in a GnRH agonist versus antagonist protocol during the first ovarian stimulation cycle." Hum Reprod, 2024;39(7):1481-94. PMID: 38723189.
- [pubmed] Pinborg A, et al. "Effectiveness and safety of follitropin delta in routine clinical practice in the Nordics and Switzerland (the NORSOS study): a prospective non-interventional study." Front Endocrinol (Lausanne), 2025;16:1613680. PMID: 40979710.
- [pubmed] Lobo R, et al. "One-year cumulative live birth rate associated with the number of oocytes in ovarian stimulation with follitropin delta: a pooled analysis of four randomized controlled trials." Hum Reprod, 2025;40(8):1526-1534. PMID: 40505136.
- [pubmed] Nelson SM, et al. "Individualized dosing of follitropin delta affects live birth and safety in in vitro fertilization treatment: an individual participant data meta-analysis of randomized controlled trials." Fertil Steril, 2024;122(3):445-454. PMID: 38750874.
Sources & Citations
Studies were read from their PubMed abstracts; no US label exists. Read October 6, 2026.
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