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 Moderna <MRNA.O> and Pfizer <PFE.N>, which has partnered with
Germany’s BioNTech <22UAy.F>, this week separately launched clinical
trials that use a new and unproven gene-based technology. Both
companies are requiring proof of a negative pregnancy test and a
commitment to using birth control from women of childbearing age who
enroll.
Drugmakers say they first need to make sure the vaccines are safe
and effective more generally. In addition, U.S. regulators require
that drugmakers conduct safety studies in pregnant animals before
the vaccines are tested in pregnant women to ensure they don't harm
the fetus or lead to miscarriage.
Bioethicists, vaccine and maternal health experts have argued for
years that pregnant women should be included early in trials of
pandemic vaccines so they would not need to wait until long after a
successful candidate emerges. That debate fell on deaf ears in
recent outbreaks of Ebola and Zika, but has taken on new urgency in
the era of COVID-19, as studies show pregnant women are at increased
risk of severe disease from the new coronavirus.
“It's a problem because if (vaccines) are not tested in pregnancy,
then they may not be available or people may not be comfortable
offering them," said Dr. Denise Jamieson, chief of gynecology and
obstetrics for Emory Healthcare in Atlanta.
According to the 2012 Census, 75.4 million U.S. women were of
childbearing age, defined as 15 to 50 years old. Currently, pregnant
women are recommended to take flu and whooping cough vaccines and
certain others depending on individual circumstances, but none of
these have been specifically tested and proven safe for pregnant
women.
“We have an enormous number of women of childbearing age and
potentially getting pregnant, and what’s the safest vaccine for
them?” said Dr. Larry Corey, a vaccine expert at Fred Hutchinson
Cancer Center in Seattle who is helping oversee vaccine trials
conducted by Moderna and other drugmakers in collaboration with the
U.S. government.
Doctors may want to see even more data for completely new vaccine
technologies, such as those used by Moderna and Pfizer, compared
with one that has already been used in pregnant women.
Such differences highlight why "we need multiple vaccines" to best
address the needs of specific populations, Corey said.
A PRECEDENT IN PREGNANCY Johnson & Johnson <JNJ.N>, which kicked off
a small-scale safety trial for its COVID-19 vaccine this week, is
using the same underlying technology that it used with its Ebola
vaccine, which has been used in 1,000 pregnant women in Democratic
Republic of Congo. Larger studies with that vaccine are now under
way.
J&J's chief scientific officer, Dr. Paul Stoffels, told Reuters the
company has done many years of "extensive" preclinical study with
the Ebola vaccine, including on pregnant animals, and "has not see
any challenges."
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Stoffels said J&J would decide in the next few weeks whether it will
include pregnant women in its large Phase 3 late-stage trial for a
COVID-19 vaccine due to start in September. Pfizer expects to start
toxicology studies in pregnant animals shortly, with data ready for
review by the U.S. Food and Drug Administration in the first quarter
of 2021. Studies in pregnant women could start some time afterward.
"We continue to explore potential ways to shorten the time to
studies in pregnant women," Dr. Bill Gruber, Pfizer's senior vice
president of vaccine clinical research and development, told
Reuters.
Of course, unplanned pregnancies can happen even when women are
using reliable contraception. Based on past experiences in such
trials, Gruber said he expects about 1% of women in Pfizer's Phase 3
trial, or about 150 women, will become pregnant. And those women and
their babies will be followed closely.
Moderna said in an emailed statement that the company launched its
safety study in pregnant animals at the end of June and expects
results by the end of this year.
"Once we have generated additional safety data for our vaccine, and
importantly demonstrated that it is efficacious, we intend to
conduct additional studies in this important population," a Moderna
spokesperson said.
Sanofi <SASY.PA>, whose coronavirus vaccine is based on its flu
vaccine platform, is doing reproductive toxicology in animals, but
those results won't be ready before the start of the company's large
Phase 3 trials, expected to start by year-end.
Sanofi may establish a pregnancy registry after the vaccine is
approved to track outcomes in pregnant women, as has been done in
the past.
Merck & Co <MRK.N> said it has not made any decisions yet on when to
test its vaccine candidate in pregnant women. Novavax <NVAX.O> and
AstraZeneca Plc <AZN.L> declined to comment on their plans.
Dr. Flor Munoz, an expert in maternal use of vaccines at Baylor
College of Medicine, said companies have been reluctant to test
anything in pregnant women since the 1950s and 60s, after the drug
thalidomide, which was used to treat nausea in pregnancy, caused
widespread birth defects. She agrees that preliminary testing is
needed.
The vaccines "need to be reasonably safe and reasonably effective,"
she said. "We don't necessarily have to finish the Phase 3 trials."
(Reporting by Julie Steenhuysen; editing by Michele Gershberg and
Leslie Adler)
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