UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

o

Rule 13d-1(b)

o

Rule 13d-1(c)

x

Rule 13d-1(d)

CUSIP No. 85858C107

1

Name of Reporting Persons.
Ivan Bergstein

2

Check the Appropriate Box if a Member of a Group. (See Instructions)

(a)

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(b)

x

3

SEC Use Only.

4

Citizenship or Place of Organization.
United States of America

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With:

5

Sole Voting Power.
2,388,211

6

Shared Voting Power.
0

7

Sole Dispositive Power.
2,388,211

8

Shared Dispositive Power.
0

9

Aggregate Amount Beneficially Owned by Each Reporting Person.
2,388,211

10

Check box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions).  o

11

Percent of Class Represented by Amount in Row (9).
13.1%*

12

Type of Reporting Person
IN

Item 1(a).

Name of Issuer:
Stemline Therapeutics, Inc. (the “Company”).

Item 1(b).

Address of Issuer’s Principal Executive Offices:
The Company’s principal executive offices are located at 750 Lexington Avenue, Eleventh Floor, New York, NY 10022.

Item 2(a).

Name of Person Filing:
Ivan Bergstein

Item 2(b).

Address of Principal Business Office, or, if none, Residence:
The individual’s principal executive offices are located at 750 Lexington Avenue, Eleventh Floor, New York, NY 10022.

Item 2(c).

Citizenship:
United States of America.

Item 2(d).

Title of Class of Securities:
Common Stock, $0.0001 par value, (the “Common Shares”).

Item 2(e).

CUSIP Number:
85858C107

Item 3.

If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), check whether the person filing is a:

Not applicable.

Item 4.

Ownership.

As of the date hereof:

(a)

Amount beneficially owned:   

Ivan Bergstein beneficially owns 2,388,211 Common Shares.

(b)

Percent of class:   

The Common Shares beneficially owned by Ivan Bergstein represent 13.1% of the Company’s outstanding Common Shares, based on 18,175,519 shares outstanding as of February 23, 2015, which is the sum of (i) 17,676,109 Common Shares reported outstanding as of February 23, 2015 based on information provided by the Company to the reporting person and (ii) 499,410 Common Shares underlying options to purchase Common Shares held by the reporting person that are exercisable within 60 days.

(c)

Number of shares as to which such person has:

(i)

Sole power to vote or direct the vote:   

Ivan Bergstein has the sole power to vote or direct the vote of the 2,388,211 Common Shares that he beneficially owns.

(ii)

Shared power to vote or to direct the vote:    

Ivan Bergstein does not share his power to vote or direct the vote of any Common Shares that he beneficially owns.

(iii)

Sole power to dispose or direct the disposition of:   

Ivan Bergstein has the sole power to dispose or direct the disposition of the 2,388,211 Common Shares that he beneficially owns.

(iv)

Shared power to dispose or to direct the disposition of:   

Ivan Bergstein does not share his power to dispose of or direct the disposition any Common Shares that he beneficially owns.

**The reporting person beneficially owns 2,388,211 Common Shares which constitute approximately 13.1% of the Company’s outstanding Common Shares.  This is based on 18,175,519 shares outstanding as of February 23, 2015, which is the sum of (i) Common Shares reported outstanding as of February 23, 2015 of 17,676,109 shares based on information provided by the Company to the reporting person and (ii) 499,410 Common Shares underlying options to purchase Common Shares held by the reporting person that are exercisable within 60 days.

Item 5.

Ownership of Five Percent or Less of a Class.

Not applicable.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

Not applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported By the Parent Holding Company.

Not applicable.

Item 8.

Identification and Classification of Member of the Group.

Not applicable.

Item 9.

Notice of Dissolution of Group.

Not applicable.

Date: March 6, 2015

By:

/s/ Ivan Bergstein, M.D.

Name:

Ivan Bergstein, M.D.

Title:

Chairman, President and Chief Executive Officer