Constellation Pharmaceuticals Raises $15 Million in Additional Funding

CAMBRIDGE, Mass. – June 6, 2011 – Constellation Pharmaceuticals, Inc., a leading
biopharmaceutical company in the field of epigenetics, today announced that it has raised $15
million in a Series B extension financing. All major current investors participated in the round,
including Third Rock Ventures, The Column Group, Venrock Associates, SR One and Altitude
Life Science Ventures. Constellation is focused on the discovery and development of small
molecule therapeutics against chromatin-based targets to treat cancer and
inflammatory/immunologic disorders. Proceeds from this round of financing will allow the
company to continue to advance product candidates in its portfolio toward clinical development.
“This financing reflects the enthusiasm of our investors for the excellent progress that
Constellation has made in discovering and developing compelling drug candidates derived from
its broad platform of capabilities applied to multiple classes of epigenetic targets,” said Mark A.
Goldsmith, M.D., Ph.D., president and chief executive officer of Constellation Pharmaceuticals.
“The recent additions to our R&D leadership team and achievement of key internal development
milestones mark our clear transition to a product focus and accelerate our trajectory toward the
clinic. This additional funding enables us to continue leveraging our expertise in chromatin
biology to expand our growing product pipeline, and it provides strategic flexibility as we
execute our overall development and business plans.”

About Constellation Pharmaceuticals
Constellation Pharmaceuticals leverages insights from the rapidly expanding field of epigenetics
to discover and develop small molecule therapeutics for the treatment of cancer,
inflammatory/immunologic disorders and other diseases. Research at Constellation and by others
has shown that abnormal epigenetic regulation of gene expression contributes to many different
diseases. The company’s innovative product discovery engine targets both the enzymes that
modify the dynamic structure of chromatin and other proteins that interact with chromatin to
control gene expression. Restoration of normal gene expression through chromatin modulation
by highly selective and specific inhibitors promises to be a powerful avenue for the development
of important new medicines against a broad range of diseases. For more information, please visit
the company's website at