EAST 501 Lecture Notes - Lecture 4: Gonadotropin Preparations, Gonadotropin-Releasing Hormone Agonist, Gonadotropin-Releasing Hormone Analogue
21 Jun 2018
School
Department
Course
Professor
Jan 17th – Lec 4 Bernard
Female infertility: Drug Development
-there is an orally active GnRH
antagonist that is probably going to
be approved in the next year
OVARIAN STIMULATION: LONG PROTOCOL
-Lupron = GnRH analogue
-goal in the future:
simplify the procedure so that it is
less stressful
LONG GnRH AGONIST PROTOCOL
-this is what the injections might look like
-at the start: daily GnRH agonist injections
LONG ACTING FSH: FSH-CTP
-Presence of 4 O-linked oligosaccharides in the unique C-terminal peptide (CTP) of hCG-beta increases serum
half-life and bioactivity
othis differentiates it from the FSH and LH beta subunit
othe glycosylation increases the half-life by slowing the glomerular filtration
-idea: CTP added to beta chain of FSH to increase half-life less injections you need to give FSH is there for
longer
-recombinant protein synthesized in CHO cells (Corifollitropin alfa) = this is a manipulation of the beta subunit
-this enables fewer injections of FSH – using other molecules to increase the half life
othis idea of modification is being used for other protein or peptide based drugs
PHARMACOLOGY OF FSH-CTP IN RATS
-Addition of CTP:
othey added either one or two copies of the C-term peptide and it made no difference
oinjected either FSH WT or the CTP-FSH into the rats
the CTP version was much longer lived
oIncreases serum half-life (decrease renal clearance)
oIncreases biopotency
oDoes not alter binding affinity
oin the rat model FSH(CTP)2 compared to FSH WT had a longer half-life (decreased clearance)
oFSH-CTP was also more potent than the WT at stimulating E2 production because it is a longer lived
molecule
oadding the C-term does not affect the binding to the receptor (does not affect the affinity)
find more resources at oneclass.com
find more resources at oneclass.com
Jan 17th – Lec 4 Bernard
Female infertility: Drug Development
PHARMACOLOTY OF FSH-CTP IN HUMANS – clinical trials
-No serious adverse drug reactions (no difference compared to the recombinant FSH)
oOHSS no different from WT FSH (RR 1.00, 95% Cl 0.74 to 1.37; 3753 participants, 9 studies)
RR = 1.00 no difference when using the FSH-CTP compared to the usual (FSH WT)
if RR = 2 the new drug is twice as likely to do “x”
ono antibodies production to CHO cell proteins or to FSH-CTP
during the purification (from the CHO cells) there is a possibility that there are some CHO
proteins that get through – in trials, no Abs were produced against the CHO proteins that got
through in the purification
oincreased half-life 2-3 fold relative to rFSH (recombinant FSH)
LIVE BIRTH AFTER OVARIAN STIMULATION
USING FSH-CTP FOR IVF
-32yo women with 7yr of primary infertility
-went through the antagonist protocol
-the points on the graph are the follicles
that are developing (their diameter is
indicated on the right y axis)
-ICSI, two embryos implanted, singleton birth
-on D3 gave herself an injection of the
FSH-CTP molecule and then no
treatment until day 10
-by using the CTP-FSH injection it
negated the need for 6 additional injections
-the GnRH antagonist was used to block the
endogenous LH surge (driven by increase in E2)
-after the first week: once the daily injections of Rec FSH, the
CTP-FSH is not used again then treats herself with hCG a couple days later there is oocyte pick up (OPU)
-they used the ICSI protocol in this case 2 embryos implanted it worked
LONG-ACTING FSH IS AS EFFECTIVE AS CONVENTIONAL FSH
-Equivalent live birth rate
oRR 0.95, 95% Cl 0.84 to 1.07; 2363 participants, 8 studies
-Approved in Europe (Jan 2010) for use in ovarian stimulation with GnRH antagonist protocol (FSH approval
pending?) did not use for the agonist protocols
othis is not used in Canada or the US yet, they gave up on the effort to get it approved for now not
because there was something wrong with the use in Europe
-In trials for use in long GnRH agonist protocol
INITIAL SCREENING FOR CANDIDATE SMALL MOLECULE GNRH RECEPTOR ANTAGONSITS IN HIGH THROUGHPUT SCREEN
-Measure ability (and affinity, Ki) of molecules to block GnRH agonist binding to human GnRH receptor expressed
in heterologous cell system (HEK293 cells)
oheterologous cell system = they do not express the GnRH receptor endogenously
need to add in the thing that you are interested in
1. took HEK293 cells – heterologous cell system
2. stably transform the cell to start expressing the human GnRHRs
3. add radioactive GnRH ability to bind to GnRHRs – as long as they are indeed there
find more resources at oneclass.com
find more resources at oneclass.com
