Onconova Therapeutics Reports Full Year 2020 Financial Results, Provides Business Update Conference call begins at 4:30 p.m. Eastern time today NEWTOWN, Pa.

Onconova Therapeutics Reports Full Year

2020 Financial Results, Provides Business Update

Conference call begins at 4:30 p.m. Eastern

NEWTOWN, Pa., March 11, 2021 (GLOBE

NEWSWIRE) - Onconova Therapeutics, Inc. (NASDAQ: ONTX) ("Onconova"), a clinical-stage biopharmaceutical

company focused on discovering and developing novel therapies for patients with cancer, announces financial results for the twelve

months ended December 31, 2020 and provides a business update.

Highlights of the fourth quarter of 2020

and recent weeks include:

Management Commentary

"The fourth quarter and recent weeks

have been active and productive at Onconova as we continue to advance our lead product ON 123300 into the clinic," said Steven

M. Fruchtman, M.D., President and Chief Executive Officer of Onconova. "We submitted an Investigational New Drug application

to the FDA for a Phase 1 study in advanced cancers including HR+/HER 2- metastatic breast cancer patients resistant to approved

second-generation CDK 4/6 inhibitors. In December 2020, we received clearance from the FDA to begin the study, and have since

received IRB approval at our first site. We expect the first patient to be enrolled in the second quarter of this year. Two further

sites are in the study set-up process.

"This Phase 1 study will assess the

safety, tolerability and pharmacokinetics of ON 123300 administered orally at increasing doses starting at 40 mg daily continuously.

"Our partner in China, HanX Pharmaceuticals,

continues enrolling a similar patient population in a Phase 1 dose-escalation study with ON 123300 at two sites. The initial dose

cohort has been completed and the second dose cohort is enrolling. We are pleased that ON 123300 appears to be well tolerated so

far as no dose-limiting toxicities have been seen to date. The HanX study is dosing patients on a 21-day cycle. Collectively, the

U.S. and China Phase 1 studies are expected to provide data regarding the safety profile of ON 123300 and potentially provide preliminary

efficacy signals in patients with advanced cancer."

Commenting on ongoing investigator-sponsored

studies with oral rigosertib, the company's RAS pathway inhibitor, Dr. Fruchtman added, "We are currently supporting

investigator-initiated studies that are exploring the use of oral rigosertib for cancers driven by mutation of the RAS gene including

a Phase 1 study in combination with a PD-1 inhibitor for patients with progressive K-RAS mutated non-small cell lung cancer.

This study is open and continues to enroll patients, with the objectives to identify the recommended Phase 2 dose and to characterize

the safety profile of the combination treatment. Results are expected in 2021.

"In addition, an investigator-initiated

Phase 1b/2 study with oral rigosertib monotherapy in advanced squamous cell carcinoma associated with recessive dystrophic epidermolysis

bullosa is open. A preclinical study is also evaluating oral rigosertib in clear cell renal carcinoma. We anticipate

additional investigator-initiated studies in RAS-driven cancers in combination with PD-1 inhibitors, including in metastatic melanoma.

Other than the cost of supplying oral rigosertib to the investigators, Onconova does not expect to incur significant expense for

these studies," Dr. Fruchtman stated.

Full Year Financial Results

Cash and cash equivalents as of December 31,

2020 were $19.0 million, compared with $22.7 million as of December 31, 2019. Subsequent to the end of the quarter, the Company

raised net proceeds of $35.2 million from two equity offerings with institutional investors. The Company expects that its cash

and cash equivalents as of February 28, 2021 will be sufficient to fund ongoing clinical trials and business operations for

more than eighteen months.

Research and development expenses were

$16.9 million for 2020, compared with $15.5 million for 2019. The increase was primarily related to higher regulatory consulting

fees and manufacturing costs related to clinical supply for ON 123300, partially offset by lower expenses for the oral rigosertib

combination program and the Phase 3 INSPIRE study in the 2020 period.

General and administrative expenses were

$8.3 million for 2020, consistent with 2019. Lower personnel and stock compensation expenses in 2020 due to personnel reductions

in the 2019 period were offset by higher pre-commercialization, insurance, and corporate legal and stockholder meeting expenses

Net loss for 2020 was $25.2 million, or

$0.14 per share on 174.0 million weighted average shares outstanding, compared with a loss of $21.5 million, or $1.49 per share

for 2019 on 14.4 million weighted average shares outstanding.

Conference Call and Webcast

Onconova will host an investment community

conference call today beginning at 4:30 p.m. Eastern time, during which management will discuss financial results for 2020,

provide a business update and answer questions. Interested parties can participate by dialing (855) 428-5741 (domestic callers)

or (210) 229-8823 (international callers) and using conference ID 3863774.

A live webcast of the conference call

will be available in the Investors & Media section of the Company's website at www.onconova.com. A replay of the

webcast will be available on the Onconova website for 90 days following the call.

About Onconova Therapeutics, Inc.

Onconova Therapeutics is a clinical-stage

biopharmaceutical company focused on discovering and developing novel therapies for patients with cancer. The Company has proprietary

targeted anti-cancer agents designed to disrupt specific cellular pathways that are important for cancer cell proliferation.

Onconova's novel, proprietary multi-kinase

inhibitor ON 123300 is planned to begin a dose-escalation and expansion Phase 1 trial in the U.S. in 2Q21, and a dose-escalation

and expansion Phase 1 trial is currently underway in China. Onconova's product candidate oral rigosertib is currently in

a dose-escalation and expansion Phase 1 investigator-initiated study targeting patients with KRAS+ lung adenocarcinoma in combination

with nivolumab. In addition, Onconova continues to conduct preclinical work investigating rigosertib in COVID-19. For more information,

please visit www.onconova.com.

Forward-Looking Statements

Some of the statements in this release

are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E

of the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995, and involve risks

and uncertainties. These statements relate to Onconova's expectations regarding the registered direct offering, its patents

and clinical development plans including patient enrollment timelines and indications for its product candidates. Onconova has

attempted to identify forward-looking statements by terminology including "believes," "estimates," "anticipates,"

"expects," "plans," "intends," "may," "could," "might," "will,"

"should," "approximately" or other words that convey uncertainty of future events or outcomes. Although Onconova

believes that the expectations reflected in such forward-looking statements are reasonable as of the date made, expectations may

prove to have been materially different from the results expressed or implied by such forward-looking statements. These statements

are only predictions and involve known and unknown risks, uncertainties, and other factors, including the success and timing of

Onconova's clinical trials and regulatory agency and institutional review board approvals of protocols, Onconova's ability

to continue as a going concern, the need for additional financing, Onconova's collaborations, market conditions and those

discussed under the heading "Risk Factors" in Onconova's most recent Annual Report on Form 10-K and quarterly reports

on Form 10-Q. Any forward-looking statements contained in this release speak only as of its date. Onconova undertakes no obligation

to update any forward-looking statements contained in this release to reflect events or circumstances occurring after its date

or to reflect the occurrence of unanticipated events.

LHA Investor Relations

ONCONOVA THERAPEUTICS, INC.

Condensed Consolidated Balance Sheets

ONCONOVA THERAPEUTICS, INC.

Condensed Consolidated Statements of

Operations (unaudited)

(in thousands, except share and per share