SEC Form 4 · accession 0001104659-15-074206

Dimension Therapeutics, Inc. · DMTX

Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗

Reporting owners

Samuel D Isaly

Director · 10% Owner

ORBIMED ADVISORS LLC

Director · 10% Owner

OrbiMed Capital GP V LLC

Director · 10% Owner

Period of report

Oct 27, 2015

Accepted (ET)

Oct 29, 2015 · 6:15 pm EDT

Rule 10b5-1 plan

unknown — predates the checkbox

Issuer CIK

0001592288

Table I — non-derivative securities

Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F1,F3,F4	Oct 27, 2015	C	3,250,085	—	A	3,250,085	I	See Footnotes
Common Stock^F2,F3,F4	Oct 27, 2015	C	1,947,613	—	A	5,197,698	I	See Footnotes
Common Stock^F3,F4	Oct 27, 2015	P	200,000	$13.00	A	5,397,698	I	See Footnotes

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Series A Preferred Stock^F1,F3,F4	—	Oct 27, 2015	C	9,500,000	D	—	—	Common Stock	3,250,085	0	I
Series B Preferred Stock^F2,F3,F4	—	Oct 27, 2015	C	5,692,874	D	—	—	Common Stock	1,947,613	0	I

Explanation of responses

F1The Series A Preferred Stock automatically converted into Common Stock, for no additional consideration, on a 2.923-for-1 basis at the closing of the Issuer's initial public offering, and had no expiration date.
F2The Series B Preferred Stock automatically converted into Common Stock, for no additional consideration, on a 2.923-for-1 basis at the closing of the Issuer's initial public offering, and had no expiration date.
F3These securities are held of record by OrbiMed Private Investments V, LP ("OPI V"). OrbiMed Capital GP V LLC ("GP V") is the sole general partner of OPI V, and OrbiMed Advisors LLC ("Advisors") is the managing member of GP V. Samuel D. Isaly ("Isaly"), a natural person, is the managing member of and owner of a controlling interest in Advisors. By virtue of such relationships, GP V, Advisors and Isaly may be deemed to have voting and investment power over the securities held by OPI V and as a result may be deemed to have beneficial ownership over such securities.
F4This report on Form 4 is jointly filed by GP V, Advisors, and Isaly. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a- 1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. The Reporting Persons have designated a representative, currently Rishi Gupta, an employee of Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.