Washington, D.C. 20549


Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB Number: 3235-0287
Estimated average burden
hours per response: 0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person*

(Last) (First) (Middle)
SUITE 1104


(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Onconova Therapeutics, Inc. [ ONTX ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 04/27/2018 P 10,147,058 A $0.425 12,244,080 I See Note(1)
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Series B Convertible Preferred Stock Purchase Warrant $0.425(2) 04/27/2018 P 10,147,058 04/27/2018 (3) Series B Preferred Stock 253,677(2)(3) $0(2)(4) 10,147,058 I See Note(1)
Explanation of Responses:
1. Tyndall Capital Partners, L.P. ("Tyndall Capital") is the general partner of Tyndall Partners, L.P. ("Tyndall"), and possesses the sole power to vote and the sole power to direct the disposition of all securities held by Tyndall. Tyndall Capital's interest in the securities reported herein is limited to the extent of its pecuniary interest in such securities, if any.
2. Each warrant ("Warrant") is exercisable into 0.025 share of Series B Convertible Preferred Stock, par value $0.01 per share ("Preferred Stock") at an exercise price of $0.425 per 0.025 share of Preferred Stock. Each 0.025 share of Preferred Stock will be convertible into one share of common stock, par value $0.01 per share (the "Common Stock"). Onconova Therapeutics, Inc. (the "Company") does not currently have a sufficient number of authorized shares of Common Stock to cover the shares issuable upon the conversion of the Preferred Stock. As a result, before any shares of Preferred Stock can be converted, the Company must obtain stockholder approval of an amendment (the "Charter Amendment") to its certificate of incorporation, as amended, to sufficiently increase its authorized shares of Common Stock to cover the conversion of all outstanding shares of Preferred Stock into Common Stock.
3. The Warrants are exercisable immediately and will expire on the eighteen (18) month anniversary of the date on which the Company publicly announces through the filing of a Current Report on Form 8-K that the Charter Amendment has been filed with the Secretary of State of the State of Delaware.
4. 10,147,058 Units purchased for $0.425 per Unit. Each Unit consists of one share of Common Stock and one Warrant.
/s/ Jeffery S. Halis, Manager of Jeffrey Management, LLC, General Partner of Tyndall Capital Partners, L.P. 05/01/2018
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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