Follitropin alfa is a human FSH preparation of rDNA origin. Because FSH is a glycoprotein,
alterations in the carbohydrate side-chain attachments afford different isoforms, which leads to
different pharmacokinetic and pharmacodynamic properties. Because it is of recombinant origin
and not isolated from urine, it is free of any additional substances, such as urinary proteins and
LH.
Like urofollitropin, it is marketed for enhancing the development of multiple follicles that can
then be induced to ovulate, via hCG administration, so that the oocytes can be collected for IVF.
It also is used in treating women who wish to become pregnant and are anovulatory because of
polycystic ovary syndrome, in whom it can enhance follicle maturation before hCG
administration for final ovulation. All commercial products can be administered by SC injection.
The RFF notation signifies Revised Formulation Female, and the RFF Pen notation indicates a
prefilled, ready-to-use device designed to make self administration easier.
Men with infertility also can benefit from therapy with follitropin alfa if their infertility is related
to hypothalamic or pituitary hormonal dysfunction and not primary testicular failure, because it induces spermatogenesis. Just as with therapy using menotropins, pretreatment with hCG is
performed for 3 months to achieve serum testosterone levels within the normal range, before
hCG and follitropin alfa therapy.
