Cancer drug finds new use as fertility treatment

A new treatment approach increases the odds
that women with a common cause of infertility
can have a baby.
The study focused on women with polycystic
ovary syndrome, or PCOS, one of the most
common causes of infertility in women. PCOS
affects about 5% to 10% of women, who
develop multiple cysts on their ovaries and
often have irregular periods, according to the
study, published Wednesday in The New
England Journal of Medicine.
Doctors have prescribed the drug clomiphene
for years to help these women conceive, but
pregnancy rates remain low, with only about
one in five getting pregnant after six treatment
cycles.
In the new study of 750 women, doctors
compared clomiphene with another drug,
letrozole, which is commonly used as a breast
cancer treatment in postmenopausal women
whose cancers are fueled by estrogen, says
Richard Legro, the study's first author and a
professor at Penn State College of Medicine.
About 28% of women randomly assigned to
take letrozole had a live birth, compared with
19% of those assigned to take clomiphene,
according to the study, funded by the National
Institutes of Health. Women underwent up to
five monthly treatment cycles with either drug.
There were no significant differences in the
rate of twins and triplets, miscarriages or birth
defects, the study says. The two drugs caused
different side effects. Among those taking
clomiphene, 33% of women developed hot
flashes, 15% had fatigue, and 8% suffered from
dizziness.
Among those taking letrozole, 22% had fatigue,
20% had hot flashes, and 12% experienced
dizziness, according to the study.
The results are likely to change medical
practice, encouraging doctors to try letrozole
first, says Charles Coddington, a professor at
Minnesota's Mayo Clinic and president of the
Society for Assisted Reproductive Technology,
who was not involved in the study.
Today, doctors typically start with clomiphene,
mostly because its side effects and safety are
well-established, then switch to letrozole only
if women don't conceive, Coddington says.
Now that letrozole appears safe, more doctors
will feel comfortable using it, says Samantha
Butts, associate professor of obstetrics and
gynecology at the Hospital of the University of
Pennsylvania.
Both clomiphene and letrozole are much less
expensive than other treatment options,
Coddington says. A cycle of these drugs,
combined with ultrasounds and blood tests,
costs about $300.
In comparison, a month's treatment with
injectable fertility drugs costs around $1,000.
In vitro fertilization, or IVF, costs about
$15,000 per attempt, Coddington says.
Legro cautions that doctors should try to
confirm his results with additional studies. He
says doctors also to need follow babies long
term, to confirm there is no increased risk of
birth defects from letrozole.