Cardiff Oncology to Present Preclinical Data with Highly Specific PLK1 Inhibitor Onvansertib at the 2026 AACR Annual Meeting

Rhea-AI Summary

Cardiff Oncology (Nasdaq: CRDF) will present new preclinical data on its oral PLK1 inhibitor onvansertib at the AACR Annual Meeting 2026 in San Diego.

The poster (Abstract 329) shows onvansertib enhanced antitumor activity and reversed resistance to trastuzumab deruxtecan (T-DXd) in therapy-resistant HER2-low breast cancer models. Presentation: April 19, 2026, 2:00 PM–5:00 PM PT. The poster will be posted to the company’s Scientific Publications page after the session.

News Market Reaction – CRDF

+0.55%

1 alert

+0.55% News Effect

On the day this news was published, CRDF gained 0.55%, reflecting a mild positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

AACR meeting dates: April 17–22, 2026 Poster session time: April 19, 2026 | 2:00 PM–5:00 PM PT Abstract number: 329 +5 more

8 metrics

AACR meeting dates April 17–22, 2026 American Association for Cancer Research Annual Meeting 2026

Poster session time April 19, 2026 | 2:00 PM–5:00 PM PT Onvansertib + T-DXd preclinical data presentation

Abstract number 329 AACR 2026 poster on HER2-low breast cancer models

Current share price $1.81 Pre-news close relative to AACR preclinical announcement

1-day move -5.73% Price change over prior 24 hours before article publication

52-week range $1.48–$4.555 Price stood 22.3% above low and 60.26% below high

Market capitalization $129,893,460 Equity value prior to AACR preclinical data news

20-day avg volume 763,039 shares Benchmark for comparing current trading activity

Market Reality Check

Price: $1.82 Vol: Volume 540,950 vs 20-day ...

normal vol

$1.82 Last Close

Volume Volume 540,950 vs 20-day average 763,039, indicating lighter-than-normal trading activity. normal

Technical Price $1.81 is trading below the 200-day MA of $2.53 and is 60.26% under the 52-week high.

Peers on Argus

CRDF fell 5.73% while several oncology peers also traded lower: ACTU -6.67%, AVT...

CRDF fell 5.73% while several oncology peers also traded lower: ACTU -6.67%, AVTX -3.74%, ONCY -2.98%, SKYE -2.43%, and GNLX -0.38%, suggesting weakness but without a clear sector-wide momentum signal.

Historical Context

5 past events · Latest: Feb 26 (Neutral)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Feb 26	Investor conferences	Neutral	-1.0%	Announced participation in three March 2026 investor conferences with webcasts.
Feb 24	Earnings & update	Positive	+12.3%	Reported full-year 2025 results and positive Phase 2 CRDF-004 efficacy data.
Feb 19	Conference presentation	Neutral	+4.5%	Planned presentation at Oppenheimer healthcare conference with virtual format.
Jan 27	Phase 2 update	Positive	-32.0%	Reported strong ORR and PFS data for onvansertib in first-line RAS-mutated mCRC.
Jan 27	Leadership changes	Neutral	-32.0%	Announced CEO/CFO departures, interim CEO appointment, and CAO promotion.

Pattern Detected

Positive clinical data have sometimes been met with negative price reactions, as seen with the late-January Phase 2 update, while earnings and business updates have drawn more supportive responses.

Recent Company History

Over the last few months, Cardiff Oncology has focused on advancing onvansertib in RAS-mutated metastatic colorectal cancer. A January 27, 2026 Phase 2 update (CRDF-004) showed a confirmed ORR of 72.2% vs 43.2% for standard of care, yet shares fell nearly 32%. Subsequent full-year 2025 results on February 24, 2026 highlighted the same efficacy data and $58.3M in cash, with a 12.35% price gain. Conference participation news in February drew modest moves. Today’s AACR-focused preclinical announcement extends the onvansertib story into HER2-low breast cancer models.

Market Pulse Summary

This announcement highlights new preclinical findings where onvansertib combined with T-DXd enhanced...

Analysis

This announcement highlights new preclinical findings where onvansertib combined with T-DXd enhanced antitumor activity and reversed resistance in HER2-low breast cancer models, to be presented at AACR 2026 on April 19, 2026 (Abstract 329). It extends Cardiff’s onvansertib story beyond RAS‑mutated mCRC, complementing prior Phase 2 data showing a 72.2% ORR vs 43.2% for standard of care. Investors may watch for how these preclinical results translate into future clinical trial designs, timelines, and any regulatory or partnering developments.

Key Terms

plk1 inhibitor, onvansertib, her2-low, trastuzumab deruxtecan, +3 more

7 terms

plk1 inhibitor medical

"new preclinical data highlighting the potential of its highly specific oral PLK1 inhibitor, onvansertib"

A PLK1 inhibitor is a drug that blocks the activity of polo‑like kinase 1, a protein that acts like a cell’s “division foreman” and helps cells copy and divide. By interrupting that signal, these drugs aim to slow or kill rapidly dividing cancer cells. Investors care because success or failure in clinical trials, safety, and regulatory approval directly affect a drug developer’s future revenue, costs, and stock value.

onvansertib medical

"its highly specific oral PLK1 inhibitor, onvansertib, in combination with trastuzumab deruxtecan"

Onvansertib is an experimental cancer drug that works by blocking a protein (PLK1) cancer cells use to divide and survive, similar to shutting down a factory’s assembly line so defective products can’t keep being made. For investors, it matters because results from clinical trials and regulatory decisions determine whether the drug can become a marketable therapy, which can significantly affect the value and prospects of companies developing or partnering on it.

her2-low medical

"reversed resistance in therapy-resistant HER2-low breast cancer models"

HER2-low describes a level of the HER2 protein found on certain cancer cells that is detectable but lower than levels historically classified as HER2-positive. Think of it like a dimmer switch rather than an on/off light; it matters to investors because patients in this middle category may become eligible for newer targeted drugs and clinical trials, which can expand market size, affect approval decisions, and change revenue prospects for drug developers.

trastuzumab deruxtecan medical

"onvansertib potentiates the antitumor efficacy of trastuzumab deruxtecan (T-DXd)"

A targeted cancer medicine that combines an antibody with a potent chemotherapy payload to seek out and kill tumor cells that express the HER2 protein; think of it as a guided missile that binds a specific cancer marker and delivers the toxic agent directly to the tumor. It matters to investors because regulatory approvals, clinical trial results, safety profile, patent protection and competition directly affect potential sales, company valuations and the outlook for related drug pipelines.

t-dxd medical

"efficacy of trastuzumab deruxtecan (T-DXd) and reverses its resistance"

t‑dxd is a targeted cancer medicine made of an antibody linked to a powerful chemotherapy drug that homes in on cells with the HER2 protein and delivers the toxic payload directly to them. Investors watch t‑dxd because clinical trial results, regulatory approvals, safety findings, and pricing determine how widely it can be used and how much revenue it could generate—think of it as a precision-guided missile whose market value depends on performance and permission to sell.

preclinical medical

"new preclinical data highlighting the potential of its highly specific oral PLK1 inhibitor"

Preclinical describes the stage of drug or medical-product development when researchers test a candidate in the lab and in animals to see if it is safe, reaches intended targets, and shows basic effectiveness before any human trials begin. For investors, preclinical status signals an early, higher‑risk opportunity where positive lab results can increase value but significant work, time, and regulatory hurdles remain — like proofing a prototype in a workshop before road testing.

antitumor activity medical

"demonstrate enhanced antitumor activity and reversal of resistance with PLK1 inhibition"

Antitumor activity describes a drug, treatment, or compound’s ability to slow, shrink, or stop the growth of tumors in laboratory tests or clinical studies; think of it like how well a weed killer reduces or eliminates unwanted plants. For investors, reported antitumor activity signals the potential effectiveness and commercial value of a therapy, influences regulatory and trial progress, and helps gauge the risk and timeline for possible revenue or further development.

AI-generated analysis. Not financial advice.

Preclinical results in therapy-resistant HER2-low breast cancer models demonstrate enhanced antitumor activity and reversal of resistance with PLK1 inhibition

SAN DIEGO, March 19, 2026 (GLOBE NEWSWIRE) -- Cardiff Oncology, Inc. (Nasdaq: CRDF), a clinical-stage biotechnology company leveraging PLK1 inhibition to develop novel therapies across a range of cancers, today announced that new preclinical data highlighting the potential of its highly specific oral PLK1 inhibitor, onvansertib, in combination with trastuzumab deruxtecan (T-DXd) will be presented at the American Association for Cancer Research Annual Meeting 2026, taking place April 17-22, 2026 in San Diego, California.

The poster presentation will showcase findings demonstrating that onvansertib enhanced the antitumor activity of T-DXd and reversed resistance in therapy-resistant HER2-low breast cancer models.

Poster Presentation Details:

• Title: PLK1 inhibitor onvansertib potentiates the antitumor efficacy of trastuzumab deruxtecan (T-DXd) and reverses its resistance in therapy-resistant HER2-low breast cancer models
• Date & Time: April 19, 2026 | 2:00 PM – 5:00 PM PT
• Abstract Number: 329
  

The poster will be made available on the Scientific Publications page of the Company’s website following the presentation.

About Onvansertib
Onvansertib is a highly specific, oral PLK1 inhibitor currently in mid-stage clinical development for RAS-mutated metastatic colorectal cancer. It is also being evaluated in multiple other cancers through investigator-initiated studies, including metastatic pancreatic ductal adenocarcinoma (mPDAC), small cell lung cancer (SCLC), triple-negative breast cancer (TNBC), and chronic myelomonocytic leukemia (CMML).

About Cardiff Oncology, Inc.
Cardiff Oncology is a clinical-stage biotechnology company advancing innovative cancer treatments focused on PLK1 inhibition, a validated oncology target with practice-changing potential. Our lead asset, onvansertib, is a highly specific, oral PLK1 inhibitor currently being evaluated in a Phase 2 trial for first-line treatment of RAS-mutated metastatic colorectal cancer (“mCRC”), addressing a large, underserved patient population with high unmet need. Onvansertib is also under investigation in other PLK1-driven cancers through ongoing investigator-initiated trials and has shown robust single agent clinical activity in hard-to-treat tumors. By targeting tumor vulnerabilities, we aim to overcome treatment resistance and deliver improved clinical outcomes for patients.

For more information, please visit https://www.cardiffoncology.com.

Investor Contact:
Candice Masse
astr partners
candice.masse@astrpartners.com

Media Contact:
Amy Bonanno
Lyra Strategic Advisory
abonanno@lyraadvisory.com

FAQ

What preclinical results will Cardiff Oncology (CRDF) present about onvansertib at AACR 2026?

Cardiff will present data showing onvansertib potentiated T-DXd efficacy and reversed resistance in HER2-low models. According to the company, the poster (Abstract 329) reports enhanced antitumor activity and reversal of therapy resistance in preclinical HER2-low breast cancer models, supporting further investigation.

When and where is Cardiff Oncology (CRDF) presenting onvansertib data at the AACR Annual Meeting 2026?

The poster presentation is scheduled for April 19, 2026, from 2:00 PM to 5:00 PM PT in San Diego. According to the company, the presentation is part of AACR Annual Meeting 2026 (April 17–22) and will be listed as Abstract 329.

What does the AACR poster Abstract 329 claim about onvansertib plus T-DXd for HER2-low cancer?

Abstract 329 reports that onvansertib enhanced antitumor activity of trastuzumab deruxtecan and reversed T-DXd resistance in models. According to the company, the findings come from therapy-resistant HER2-low breast cancer preclinical studies demonstrating potentiation and resistance reversal.

Will Cardiff Oncology (CRDF) make the onvansertib AACR poster available online after the presentation?

Yes. The company said the poster will be posted to its Scientific Publications page after the presentation. According to the company, attendees can view Abstract 329 at the meeting and access the poster online post-session for detailed methods and results.

How might the AACR 2026 onvansertib poster affect Cardiff Oncology's (CRDF) clinical program timeline?

The poster presents preclinical evidence that may support further clinical evaluation but does not announce trials or timelines. According to the company, the data show enhanced activity in models, which could inform future clinical planning without committing to specific dates.

What is the specific focus of Cardiff Oncology's (CRDF) AACR poster on April 19, 2026?

The poster focuses on PLK1 inhibition by onvansertib combined with trastuzumab deruxtecan in therapy-resistant HER2-low breast cancer models. According to the company, the study highlights potentiation of T-DXd efficacy and reversal of resistance in preclinical models.