Onconova Therapeutics Reports Corporate Update and Announces Second Quarter 2023 Financial Results Anticipate topline results from the Phase 1 monotherapy and Phase 1/2 combination study with letrozole in Q4 2023 Plans a

Onconova Therapeutics

Reports Corporate Update and Announces Second Quarter 2023 Financial Results

topline results from the Phase 1 monotherapy and Phase 1/2 combination study with letrozole in Q4 2023

for a registrational trial with rigosertib in patients with RDEB-associated squamous cell carcinoma based on a constructive Type B FDA

meeting held in June

Company to host conference call and webcast

at 4:30 p.m. ET on Thursday, August 10, 2023

NEWTOWN, PA August 10, 2023 (GLOBE NEWSWIRE)

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

company focused on discovering and developing novel products for patients with cancer, today reported second quarter 2023 financial results

and provided an update on recent pipeline progress. Management plans to host a conference call and live webcast at 4:30 p.m. ET today

to discuss these results.

"We are very encouraged about the recent

progress that the Onconova team has made for our two lead programs, narazaciclib, a differentiated multikinase CDK4/6 inhibitor targeting

proteins involved in resistance pathways , and rigosertib, a cell signaling inhibitor, over the last few months, while effectively managing

our financial resources. In addition, we are pleased that Victor Moyo, M.D., a highly experienced and successful clinical researcher

and drug developer, has agreed to join the Company as Consulting Chief Medical Officer. We look forward to sharing several important

updates in the coming months," said Steve Fruchtman, M.D., President and Chief Executive Officer.

Dr. Fruchtman continued, "For narazaciclib,

our efforts have been dedicated to completing a Phase 1 program and defining a recommended Phase 2 dose to support evaluation of narazaciclib

in a randomized trial. Onconova believes this CDK4/6 compound has the potential to provide differentiated efficacy based on targeting

proteins that have been implicated in resistance mechanisms and the potential for an improved safety profile. We are pleased to see target

engagement based on an assay measuring proliferation. We expect to report the results from our Phase 1 monotherapy and Phase 1/2 combination

study with letrozole in Q4 2023. The readout will include safety, pharmacokinetics and the definition of a recommended Phase 2 dose."

Dr. Fruchtman concluded, "For rigosertib,

we continue to believe this rigosertib's unique action on cell signaling pathways, including K-RAS and PLK-1, combined with an

acceptable safety profile, could position it as an attractive anti-cancer agent. In June, we had a constructive Type B meeting with the

FDA for the use of rigosertib monotherapy in the lead, ultra-rare indication of RDEB-associated squamous cell carcinoma. Based on that

meeting and the impressive clinical responses in previously refractory patients we have seen and presented at major medical meetings,

we plan to design a registrational trial and will look to provide an update on next steps in H1 2024. In the meantime, we continue to

support two investigator sponsored studies for rigosertib, underway in melanoma and KRAS mutated non-small cell lung cancer which includes

any KRAS mutation that may be present."

Second Quarter Financial Results

Cash and cash equivalents as of June 30, 2023,

were $29.7 million, compared to $38.8 million as of December 31, 2022. The Company believes that its cash and cash equivalents will be

sufficient to fund ongoing clinical trials and business into the second quarter of 2024.

Research and development expenses were $2.5 million

for the second quarter of 2023, compared with $2.0 million for the second quarter of 2022.

General and administrative expenses were $2.2

million for the second quarter of 2023, compared with $2.1 million for the second quarter of 2022.

Net loss for the second quarter of 2023 was $4.3

million, or $0.20 per share on 21.0 million weighted shares outstanding, compared with a net loss of $4.0 million, or $0.19 per share

for the second quarter of 2022 on 20.9 million weighted shares outstanding.

Conference Call and Webcast Information

Interested parties who wish to participate in

the conference call may do so by dialing:

Those interested in listening to the conference

call via the internet may do so by visiting the investors and media page on the Company's website at www.onconova.com and

clicking on the webcast link. In addition to the live webcast, a replay will be available on the Onconova website for 90 days following

About Onconova Therapeutics, Inc.

Onconova Therapeutics is a clinical-stage biopharmaceutical

company focused on discovering and developing novel products for patients with cancer. The Company's product candidates include

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 narazaciclib (formerly ON 123300) is being evaluated in a Phase 1/2 combination trial with the estrogen blocker, letrozole,

in advanced low grade endometrial cancer (NCT05705505). Based on preclinical and

clinical studies of CDK 4/6 inhibitors, Onconova is also evaluating opportunities for combination studies with narazaciclib and letrozole

in additional indications.

Onconova's product candidate rigosertib

is being studied in multiple investigator-sponsored studies. These studies include a dose-escalation and expansion Phase 1/2a study of

oral rigosertib in combination with nivolumab in patients with KRAS+ non-small cell lung cancer (NCT04263090),

a Phase 2 program evaluating oral or IV rigosertib monotherapy in advanced squamous cell carcinoma complicating recessive dystrophic

epidermolysis bullosa (RDEB-associated SCC (NCT03786237, NCT04177498), and

a Phase 2 trial evaluating rigosertib in combination with pembrolizumab in patients with metastatic melanoma(NCT05764395).

For more information, please visit www.onconova.com.

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 its clinical development and

trials, its product candidates and its business and financial position. Onconova has attempted to identify forward-looking

statements by terminology including "believes," "estimates," "anticipates," "expects,"

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

"preliminary," "encouraging," "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, investigator-sponsored trials, regulatory agency and institutional review

board approvals of protocols, 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.

ONCONOVA THERAPEUTICS, INC.

Condensed Consolidated Balance Sheets

ONCONOVA THERAPEUTICS, INC.

Condensed Consolidated Statements

of Operations (unaudited)

(in thousands, except share and per share amounts)