Millendo Therapeutics Announces Successful Merger Completion

– Merger with OvaScience Closed –

– Shares of Combined Company to Commence Trading on the Nasdaq
Capital Market Under New Symbol “MLND” on Monday, December 10th, 2018 –

– Proceeds of $85.4 Million to Fund Orphan Endocrine Pipeline –

– Pivotal Phase 2b/3 Trial for Prader-Willi Syndrome Initiating in
1Q19 –

ANN ARBOR, Mich.–(BUSINESS WIRE)–Millendo
Therapeutics, Inc.
(Nasdaq: MLND), a clinical-stage
biopharmaceutical company focused on developing novel treatments for
orphan endocrine diseases, today announced that the proposed merger with
OvaScience, Inc. has closed, following the approval of OvaScience’s
stockholders received on December 4, 2018. The combined company will
operate under the name Millendo Therapeutics and will focus on the
further development of Millendo’s leading orphan endocrine pipeline,
including livoletide, a potential first-in-class treatment for
Prader-Willi syndrome (PWS), which Millendo expects will enter a pivotal
Phase 2b/3 trial in the first quarter of 2019, and nevanimibe, which is
in Phase 2b clinical development for the treatment of classic congenital
adrenal hyperplasia (CAH). Millendo shares will continue to trade on the
Nasdaq Capital Market under OvaScience’s ticker symbol “OVAS” on Friday,
December 7, 2018, and, during such time, Nasdaq share numbers will not
reflect the one-for-fifteen reverse split that occurred on December 6,
2018. Millendo Therapeutics shares will commence trading on the Nasdaq
Capital Market under the new ticker symbol “MLND” and will reflect the
one-for-fifteen reverse split in trading on Monday, December 10, 2018.

“The closing of the merger and concurrent financing represents a
significant opportunity and milestone for Millendo, as we can now
accelerate our work to bring life-changing therapies to market for rare
endocrine diseases. We have two differentiated, late-stage endocrine
therapies that have been observed to be well tolerated, and we believe
address areas of significant unmet need,” said Julia C. Owens, Ph.D.,
President and Chief Executive Officer of Millendo. “In September 2018,
we initiated our Phase 2b trial of nevanimibe in CAH, and we look
forward to the planned initiation of our pivotal Phase 2b/3 trial of
livoletide for PWS in the first quarter of 2019.”

Millendo has received total proceeds of $85.4 million, which includes
$35.9 million in net cash from OvaScience and $49.5 million from an
associated financing. Investors participating in the financing include
Great Point Partners, New Enterprise Associates, Frazier Healthcare
Partners, and Roche Venture Fund, among others. Jefferies and Leerink
Partners acted as Joint Placement Agents for the Millendo financing.

Dr. Owens continued, “Millendo now has a strong balance sheet and
sufficient cash runway to support our operations beyond anticipated
results from both trials in the first half of 2020 – the three month
placebo-controlled portion of our pivotal Phase 2b/3 trial of livoletide
in PWS and our Phase 2b clinical trial of nevanimibe in CAH.”

In connection with the closing of the merger, OvaScience completed a
one-for-fifteen reverse stock split. As a result of the reverse stock
split, every fifteen shares of OvaScience common stock outstanding
immediately prior to the merger was combined and reclassified into one
share of OvaScience common stock. No fractional shares are being issued
in connection with the reverse stock split. Instead of fractional
shares, cash will be issued based on the closing price of OvaScience
common stock on the Nasdaq Capital Market on December 4, 2018.

As a result of the closing of the merger, Millendo stockholders and
option holders own or have rights to acquire 63.3% of the combined
company, and former OvaScience stockholders will own 16.5% of the
combined company. Investors participating in the associated financing
will own 20.2% of the combined company.

The combined company will operate under the leadership of Millendo’s
President and Chief Executive Officer, Julia Owens, and will be
headquartered in Ann Arbor, Michigan. The board of directors is
comprised of eight members, including Carol Gallagher, Pharm. D., Habib
Dable, Mary Lynne Hedley, Ph.D., James Hindman, John Howe, M.D., Carole
Nuechterlein, J.D., Julia Owens, Ph.D., and Randall Whitcomb, M.D. Dr.
Gallagher is the new Chairman of the board of directors.

About Millendo’s Lead Programs
Millendo’s lead asset,
livoletide, is an unacylated ghrelin analogue being developed for the
treatment of Prader-Willi syndrome (PWS), a rare genetic disease
characterized by hyperphagia, a chronic unrelenting hunger, that leads
to obesity, metabolic dysfunction, reduced quality of life and early
mortality. In a randomized, double-blind, placebo-controlled Phase 2
clinical trial in 47 patients with PWS, Millendo observed that
administration of livoletide once daily was associated with a clinically
meaningful improvement in hyperphagia, as well as a reduction in
appetite. Millendo has received orphan drug designation for livoletide
from the U.S. Food and Drug Administration, or FDA, and the European
Medicines Agency, or EMA, for the treatment of PWS. Millendo expects to
initiate a pivotal Phase 2b/3 clinical trial of livoletide in PWS
patients in the first quarter of 2019.

Millendo is also developing nevanimibe, an ACAT1 inhibitor for the
treatment of two orphan adrenal diseases: classic congenital adrenal
hyperplasia (CAH) and endogenous Cushing’s syndrome (CS). CAH is a rare,
monogenic adrenal disease that requires lifelong treatment with
exogenous cortisol, often at high doses, which can make it difficult for
physicians to appropriately treat CAH without causing adverse
consequences. Nevanimibe has received orphan drug designation from the
FDA for the treatment of CAH and CS, as well as from the EMA for the
treatment of CAH. In a Phase 2 proof-of-concept clinical trial, Millendo
observed nevanimibe to be associated with clear signs of clinical
activity in seven of 10 treated patients and was reported to be well
tolerated at all dose levels. Millendo initiated the Phase 2b trial of
nevanimibe in CAH in September 2018. A Phase 2 trial of nevanimibe for
the treatment of patients with CS is ongoing at clinical sites in the
United States and United Kingdom.

About Millendo Therapeutics, Inc.
Millendo Therapeutics is a
late-stage biopharmaceutical company focused on developing novel
treatments for orphan endocrine diseases where current therapies do not
exist or are insufficient. The Company’s objective is to build a leading
endocrine company that creates distinct and transformative treatments
for a wide range of endocrine diseases where there is a significant
unmet medical need. The Company is currently advancing livoletide for
the treatment of Prader-Willi syndrome and nevanimibe for the treatment
of classic congenital adrenal hyperplasia and endogenous Cushing’s
syndrome. For more information, please visit www.millendo.com.

Cautionary Statement Regarding Forward-Looking Statements

Certain statements contained in this communication regarding matters
that are not historical facts, are forward-looking statements within the
meaning of Section 21E of the Securities Exchange Act of 1934, as
amended, and the Private Securities Litigation Reform Act of 1995, known
as the PSLRA. These include statements regarding management’s
intentions, plans, beliefs, expectations or forecasts for the future,
and, therefore, you are cautioned not to place undue reliance on them.
No forward-looking statement can be guaranteed, and actual results may
differ materially from those projected. Millendo undertakes no
obligation to publicly update any forward-looking statement, whether as
a result of new information, future events or otherwise, except to the
extent required by law. We use words such as “anticipates,” “believes,”
“plans,” “expects,” “projects,” “future,” “intends,” “may,” “will,”
“should,” “could,” “estimates,” “predicts,” “potential,” “continue,”
“guidance,” and similar expressions to identify these forward-looking
statements that are intended to be covered by the safe-harbor provisions
of the PSLRA. Such forward-looking statements are based on our
expectations and involve risks and uncertainties; consequently, actual
results may differ materially from those expressed or implied in the
statements due to a number of factors, including, but not limited to,
those described in the documents OvaScience, Inc. has filed with the
Securities and Exchange Commission with regard to the merger among
OvaScience, Millendo and Orion Merger Sub, Inc., including Millendo’s
plans to develop and commercialize its product candidates, including
livoletide and nevanimibe; the timing of initiation of Millendo’s
planned clinical trials; the timing of the availability of data from
Millendo’s clinical trials; the timing of any planned investigational
new drug application or new drug application; Millendo’s plans to
research, develop and commercialize its current and future product
candidates; Millendo’s ability to successfully collaborate with existing
collaborators or enter into new collaborations, and to fulfill its
obligations under any such collaboration agreements; the clinical
utility, potential benefits and market acceptance of Millendo’s product
candidates; Millendo’s commercialization, marketing and manufacturing
capabilities and strategy; Millendo’s ability to identify additional
products or product candidates with significant commercial potential;
developments and projections relating to Millendo’s competitors and our
industry; the impact of government laws and regulations; Millendo’s
ability to protect its intellectual property position; and Millendo’s
estimates regarding future revenue, expenses, capital requirements and
need for additional financing following the merger.

New factors emerge from time to time and it is not possible for us to
predict all such factors, nor can we assess the impact of each such
factor on the business or the extent to which any factor, or combination
of factors, may cause actual results to differ materially from those
contained in any forward-looking statements. Forward-looking statements
included in this release are based on information available to Millendo
as of the date of this release. Millendo disclaims any obligation to
update such forward- looking statements to reflect events or
circumstances after the date of this release, except as required by
applicable law.

Contacts

Millendo Media Contact:
Kari Watson
MacDougall
Biomedical Communications
781-235-3094
kwatson@macbiocom.com

Millendo Investor Contact:
Stephanie Ascher
Stern
Investor Relations
212-362-1200
stephanie@sternir.com