13D Filing: RA Capital Management and Dicerna Pharmaceuticals Inc (DRNA)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of
1934

(Amendment No. 5)*

 

Dicerna Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

253031108

(CUSIP Number)

RA Capital Management, LLC

20 Park Plaza, Suite 1200

Boston, MA 02116

Telephone: 617.778.2512

Attn: Peter Kolchinsky

(Name, Address and Telephone Number of Person
Authorized to
Receive Notices and Communications)

March 23, 2018

(Date of Event Which Requires Filing of
this Statement)

If the filing person has previously filed a statement on Schedule 13G
to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e),
240.13d-1(f) or 240.13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a
signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to
be sent.

* The remainder of this cover page shall be filled out for a
reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment
containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page
shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”)
or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however,
see the Notes).

CUSIP No. 253031108

1	Names of Reporting Persons. RA Capital Management, LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions)
	(a) ¨
	(b) ¨
3	SEC Use Only
4	Source of Funds (See Instructions): AF
5	Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e): ¨
6	Citizenship or Place of Organization.     Massachusetts
Number of Shares Beneficially Owned by Each Reporting Person With		7 Sole Voting Power     0
		8 Shared Voting Power      3,933,489
		9 Sole Dispositive Power     0
		10 Shared Dispositive Power  3,933,489
11	Aggregate Amount Beneficially Owned by Each Reporting Person 3,933,489
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)     ¨
13	Percent of Class Represented by Amount in Row (11) 7.6%1
14	Type of Reporting Person (See Instructions) IA, OO (Limited Liability Company)

 

 

¹
Represents 3,933,489 shares of the common stock (the “Common Stock”) of Dicerna Pharmaceuticals, Inc.
(the “Issuer”) which constitutes approximately 7.6% of the class outstanding. The percentage calculation assumes that
there are currently 51,766,999 outstanding shares of the Common Stock of the Issuer, based on the Issuer’s Form 10-K as
filed with the Securities and Exchange Commission (“SEC”) on March 8, 2018. 

 

CUSIP No. 253031108

1	Names of Reporting Persons. Peter Kolchinsky
2	Check the Appropriate Box if a Member of a Group (See Instructions)
	(a) ¨
	(b) ¨
3	SEC Use Only
4	Source of Funds (See Instructions): AF
5	Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e): ¨
6	Citizenship or Place of Organization.    United States
Number of Shares Beneficially Owned by Each Reporting Person With		7 Sole Voting Power     0
		8 Shared Voting Power      3,933,489
		9 Sole Dispositive Power     0
		10      Shared Dispositive Power  3,933,489
11	Aggregate Amount Beneficially Owned by Each Reporting Person 3,933,489
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)     ¨
13	Percent of Class Represented by Amount in Row (11) 7.6%2
14	Type of Reporting Person (See Instructions) HC, IN

 

 

²
Represents 3,933,489 shares of the common stock (the “Common Stock”) of Dicerna Pharmaceuticals, Inc.
(the “Issuer”) which constitutes approximately 7.6% of the class outstanding. The percentage calculation assumes that
there are currently 51,766,999 outstanding shares of the Common Stock of the Issuer, based on the Issuer’s Form 10-K as
filed with the Securities and Exchange Commission (“SEC”) on March 8, 2018. 

 

 

CUSIP
No. 253031108

 

1	Names of Reporting Persons. RA Capital Healthcare Fund, L.P.
2	Check the Appropriate Box if a Member of a Group (See Instructions)
	(a) ¨
	(b) ¨
3	SEC Use Only
4	Source of Funds (See Instructions): WC
5	Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e): ¨
6	Citizenship or Place of Organization.     Delaware
Number of Shares Beneficially Owned by Each Reporting Person With		7 Sole Voting Power     0
		8 Shared Voting Power      3,446,728
		9 Sole Dispositive Power     0
		10 Shared Dispositive Power  3,446,728
11	Aggregate Amount Beneficially Owned by Each Reporting Person 3,446,728
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)    ¨
13	Percent of Class Represented by Amount in Row (11) 6.7%3
14	Type of Reporting Person (See Instructions) PN (Limited Partnership)

³
Represents 3,446,728 shares of the common stock (the “Common Stock”) of Dicerna Pharmaceuticals, Inc.
(the “Issuer”) which constitutes approximately 6.7% of the class outstanding. The percentage calculation assumes that
there are currently 51,766,999 outstanding shares of the Common Stock of the Issuer, based on the Issuer’s Form 10-K as
filed with the Securities and Exchange Commission (“SEC”) on March 8, 2018.

 

Explanatory Note

This Amendment No. 5 to
Schedule 13D (this “Amendment No. 5”) amends and supplements the Statement on Schedule 13D filed with the United
States Securities and Exchange Commission on February 5, 2014, as amended to date (the “Statement”) by (i) RA
Capital Management, LLC (the “RA Capital”), (ii) Peter Kolchinsky and (iii) RA Capital Healthcare Fund, L.P.
(“Fund” and together with each of the foregoing, the “Reporting Persons”), relating to the Common
Stock (the “Common Stock”) of Dicerna Pharmaceuticals, Inc. (the “Issuer”). Capitalized terms
used herein without definition shall have the meaning set forth in the Statement.

Item
5. Interest in Securities of the Issuer

Item 5(a)-(b) of the Statement is hereby amended
and restated in its entirety as follows:

(a)-(b) See Items 7-11 of the cover pages
and Item 2 of this Statement.

Item 5(c) of the Statement is hereby amended
and supplemented by adding the following:

(c) From the date of the most recent amendment
to this Schedule 13D through March 23, 2018, the Reporting Persons disposed of 528,824 shares of Common Stock in a series of open
market transactions on the Nasdaq Global Market. Details by date of the transactions are as follows:

Transaction	Date	No. Shares	Price
Sell	19-Mar-2018	84,670	$12.6308
Sell	19-Mar-2018	34,700	$12.4550
Sell	20-Mar-2018	50,000	$11.0000
Sell	20-Mar-2018	55,200	$11.1555
Sell	20-Mar-2018	67,985	$11.1648
Sell	21-Mar-2018	64,600	$11.2399
Sell	21-Mar-2018	31,145	$11.0718
Sell	21-Mar-2018	49,000	$11.1400
Sell	21-Mar-2018	36,224	$11.1727
Sell	23-Mar-2018	55,300	$11.0511

(d) None.

(e) Not Applicable.

SIGNATURE

After reasonable inquiry
and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 27, 2018

RA CAPITAL MANAGEMENT, LLC

By: /s/ Rajeev Shah

————————————————-

Rajeev Shah

Authorized Signatory

PETER KOLCHINSKY

/s/ Peter Kolchinsky

————————————————-

 

 

RA CAPITAL HEALTHCARE FUND, L.P.

By: RA Capital Management, LLC

Its: General Partner

By: /s/ Rajeev Shah

————————————————-

Rajeev Shah

Authorized Signatory