Corifollitropin Alfa
Corifollitropin alfa is a long-acting recombinant FSH analogue: a single injection provides about a week of sustained follicle-stimulating activity, replacing the first seven daily FSH injections in an IVF antagonist protocol. It reduces injection burden during controlled ovarian stimulation.
01 Overview
Corifollitropin alfa is engineered by fusing the C-terminal peptide of hCG's beta subunit onto FSH, dramatically extending its half-life. One subcutaneous dose sustains multifollicular growth for roughly seven days.
It is used in GnRH antagonist IVF protocols; after day seven, if further stimulation is needed, daily FSH is added. Dosing is weight- and age-banded rather than titrated daily.
02 Mechanism
The CTP-modified FSH binds ovarian FSH receptors with a prolonged half-life, giving sustained follicular stimulation from a single injection.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Lower body-weight band | 100 mcg | SubQ | 100 mcg single dose if <=60 kg (age criteria apply) |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Sustained follicular stimulationOne injection replaces seven days of daily FSH, easing patient burden. | Clinical | ||
| Comparable IVF outcomesOngoing pregnancy rates similar to daily recombinant FSH in trials. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Ovarian hyperstimulation syndrome (OHSS)The fixed long-acting dose cannot be reduced once given, so a high responder is at OHSS risk. | Severe | Uncommon | Clinical | |
| Pelvic discomfortBloating and pelvic pain from ovarian enlargement. | Mild | Common | Clinical |