CUSIP No. 039697107
|
SCHEDULE 13G/A
|
Page 4
of 9 Pages
|
|
|
|
|
|
1
|
NAME OF REPORTING
PERSONS
Rock Springs Capital Master Fund LP
|
2
|
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
(a)
o
(b)
o
|
|
3
|
SEC USE ONLY
|
4
|
CITIZENSHIP OR PLACE OF ORGANIZATION
Cayman Islands
|
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON
WITH
|
5
|
SOLE VOTING POWER
0
|
6
|
SHARED VOTING POWER
2,415,744
|
7
|
SOLE DISPOSITIVE POWER
0
|
8
|
SHARED DISPOSITIVE POWER
2,415,744
|
9
|
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
2,415,744
|
10
|
CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
|
o
|
11
|
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.07%
|
12
|
TYPE OF REPORTING PERSON
PN
|
CUSIP No. 039697107
|
SCHEDULE 13G/A
|
Page 5
of 9 Pages
|
Item 1.
|
|
(a) Name of Issuer
|
Ardelyx,
Inc. (the “Issuer”)
|
|
(b) Address of Issuer’s Principal
Executive Offices
|
34175 Ardenwood Blvd., Suite 200
Fremont, CA 94555
Item 2.
|
|
(a) Name of Person Filing
|
This
Statement is filed on behalf of each of the following persons (collectively, the “Reporting Persons”):
i.
Rock Springs Capital Management LP (“RSCM”);
ii.
Rock Springs Capital LLC (“RSC”); and
iii.
Rock Springs Capital Master Fund LP (“Master Fund”).
This
Statement relates to Shares (as defined herein) held directly by the Master Fund, which is a Cayman Island exempted
limited partnership, and indirectly held by RSCM, a Delaware limited partnership, and RSC, a Delaware limited liability
company. RSCM serves as the investment manager to the Master Fund. RSC is the general partner of RSCM.
|
|
(b) Address
of Principal Business Office, or, if none, Residence
|
Rock
Springs Capital Management LP and Rock Springs Capital LLC
650 South Exeter, Suite 1070
Baltimore, MD 21202
Rock
Springs Capital Master Fund LP
c/o Walkers Corporate Limited
Cayman Corporate Centre
27 Hospital Road
George Town, Grand Cayman, KY1-9008, Cayman Islands
Rock
Springs Capital Management LP - Delaware
Rock
Springs Capital LLC - Delaware
Rock
Springs Capital Master Fund LP - Cayman Islands
|
|
(d) Title of Class of Securities
|
Common
Stock, par value, $0.0001 per share (the “Shares”)
039697107
CUSIP No. 039697107
|
SCHEDULE 13G/A
|
Page 6
of 9 Pages
|
|
Item 3. If
this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
Not Applicable.
|
|
(a)
|
¨
|
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
|
|
|
(b)
|
¨
|
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
|
|
|
(c)
|
¨
|
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
|
|
|
(d)
|
¨
|
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
|
|
|
(e)
|
o
|
An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);
|
|
|
(f)
|
¨
|
An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);
|
|
|
(g)
|
¨
|
A parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G);
|
|
|
(h)
|
¨
|
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
|
|
|
(i)
|
¨
|
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the
Investment Company Act of 1940 (15 U.S.C. 80a-3);
|
|
|
(j)
|
¨
|
A non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J);
|
|
|
(k)
|
¨
|
A group, in accordance with §240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
|
|
|
|
|
CUSIP
No. 039697107
|
SCHEDULE 13G/A
|
Page
7 of 9 Pages
|
Item
4. Ownership
Provide
the following information regarding the aggregate number and percentage of the class of securities of the issuer identified
in Item 1.
As of the date of this filing, the Reporting Persons may be deemed beneficial owners of 2,415,744 shares of Common Stock.
The Reporting Persons hold 2,275,557 shares of Common Stock and 140,187 warrants to purchase Common Stock. The percent of
class is based on a total of 47,675,166 shares of Common Stock outstanding, which is the sum of: (1) 47,534,979 shares outstanding
as of November 1, 2017; and (ii) 140,187 shares of Common Stock that the Reporting Persons have the right to acquire upon
exercise of the warrants.
(a) Amount
beneficially owned:
Rock Springs Capital
Management LP: 2,415,744
Rock
Springs Capital LLC: 2,415,744
Rock Springs Capital Master
Fund LP: 2,415,744
(b) Percent
of class:
Rock Springs Capital
Management LP: 5.07%
Rock
Springs Capital LLC: 5.07%
Rock Springs Capital Master
Fund LP: 5.07%
(c) Number
of shares as to which the person has:
(i) Sole
power to vote or to direct the vote:
Rock Springs Capital
Management LP: 0
Rock
Springs Capital LLC: 0
Rock Springs Capital Master
Fund LP: 0
(ii)
Shared power to vote or to direct the vote:
Rock Springs Capital
Management LP: 2,415,744
Rock
Springs Capital LLC: 2,415,744
Rock Springs Capital Master
Fund LP: 2,415,744
(iii)
Sole power to dispose or to direct the disposition of:
Rock Springs Capital
Management LP: 0
Rock
Springs Capital LLC: 0
Rock Springs Capital Master
Fund LP: 0
(iv)
Shared power to dispose or to direct the disposition of:
Rock Springs Capital
Management LP: 2,415,744
Rock
Springs Capital LLC: 2,415,744
Rock Springs Capital Master
Fund LP: 2,415,744
Item
5. Ownership of Five Percent or Less of a Class
If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the
beneficial owner of more than five percent of the class of securities, check the following
Not
Applicable
. Please see response to Item 2.