EXHIBIT 99.1

The Reporting Person is an employee of OrbiMed Advisors
LLC (Advisors), a registered adviser under the
Investment Advisors Act of 1940, as amended. Upon
vesting of the restricted stock unit award, ownership
of the shares underlying the restricted stock unit award
will be transferred to ROS Acquisition Offshore LP
(ROS Acquisition) and OrbiMed Royalty Opportunities II, LP
(ORO II). Advisors is the investment manager of ROS
Acquisition. Advisors is also the investment manager of
Royalty Opportunities S.a.r.l., of which ROS Acquisition
is a wholly-owned subsidiary. OrbiMed ROF II LLC (ROF II)
is the sole general partner of ORO II, and Advisors is
the sole managing member of ROF II. By virtue of such
relationships, Advisors may be deemed to have voting and
investment power with respect to the securities held by ROS
Acquisition and ORO II and, as a result, may be deemed to
have beneficial ownership over such securities. Advisors
exercises its investment and voting power through a
management committee comprised of Carl L. Gordon, Sven H.
Borho, and Jonathan T. Silverstein, each of whom disclaims
beneficial ownership of the securities held by ROS
Acquisition and ORO II.