Aprea Therapeutics Provides ACESOT-1051 Program Update for WEE1 Inhibitor APR-1051: Accelerating and Expanding Enrollment. Clinical Data Presentation Planned for Q4 2026
Rhea-AI Summary
Aprea Therapeutics (Nasdaq: APRE) provided a program update on its oral WEE1 inhibitor APR-1051 from the ongoing Phase 1 dose-escalation ACESOT-1051 trial. The next clinical data update is planned for a medical meeting in Q4 2026, following earlier observations of single-agent activity and a favorable tolerability profile in difficult-to-treat cancers.
According to Aprea, enrollment in ACESOT-1051 is accelerating, with active clinical sites increasing from three to ten and expected enrollment of 6–10 patients per month by Q4 2026. The company is expanding enrollment to include at least 50 patients with uterine serous carcinoma or Cyclin E–overexpressing platinum-resistant ovarian cancer, and anticipates completing dose escalation and backfill expansion in Q2 2027.
Aprea also plans new combination regimens, adding arms in HPV-positive head and neck squamous cell carcinoma (with immune checkpoint therapy) and colorectal cancer (with standard chemotherapy), using dose levels that have cleared safety review and shown single-agent activity, supported by preclinical antitumor and synergy data.
Positive
- Clinical sites expanded from 3 to 10 to support faster APR-1051 enrollment
- Enrollment ramp target of 6–10 ACESOT-1051 patients per month by Q4 2026
- At least 50 patients planned in uterine serous carcinoma and Cyclin E–overexpressing PROC
- New combination arms planned in HPV-positive head and neck and colorectal cancer using cleared dose levels
Negative
- None.
Key Figures
Previous Clinical trial Reports
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Jun 01 | Phase 1 data | Positive | -8.6% | Updated Phase 1 data showed early monotherapy activity and manageable tolerability. |
| Apr 21 | Clinical presentation | Positive | -7.5% | ASCO abstract acceptance announced for early ACESOT-1051 clinical results. |
| Mar 30 | Partial response | Positive | +8.2% | Confirmed partial response reported in the ongoing Phase 1 ACESOT-1051 trial. |
| Oct 15 | Dose selection | Negative | -1.3% | ATRN-119 monotherapy enrollment was paused as combination strategies were prioritized. |
| Jun 25 | Early clinical data | Positive | +10.1% | APR-1051 showed early clinical activity and preclinical combination synergy. |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
The clinical-tag history included reactions of -8.59%, -7.51%, +8.2%, -1.32%, and +10.09%, averaging 0.17%.
Key Terms
wee1 inhibitor medical
dose escalation medical
uterine serous carcinoma medical
immune checkpoint therapy medical
AI-generated analysis. How Rhea-AI works. Not financial advice.
- Next clinical data update from the ongoing Phase 1 dose escalation ACESOT-1051 trial anticipated at a medical meeting in Q4 2026, providing a near-term opportunity to demonstrate continued clinical progress with APR-1051
- Enrollment in ACESOT-1051 is accelerating as the Company advances dose escalation and amasses the clinical data needed to inform dose selection and subsequent development
- Aprea plans to advance APR-1051 in uterine serous carcinoma (USC) and Cyclin E–overexpressing platinum-resistant ovarian cancer (PROC) while also evaluating combination regimens with standard of care in HPV-positive head and neck cancer and colorectal cancer, utilizing dose levels that have shown single-agent activity and cleared safety review
- The expanded development strategy builds on emerging single-agent activity and positions APR-1051 across biomarker-defined indications where WEE1 inhibition may address significant unmet medical need
DOYLESTOWN, Pa., July 30, 2026 (GLOBE NEWSWIRE) -- Aprea Therapeutics, Inc. (Nasdaq: APRE) (“Aprea”, or the “Company”), a clinical-stage precision medicine oncology company focused on the discovery and development of targeted therapies for patients with biomarker-defined cancers, today provided an update on the ongoing Phase 1 dose escalation ACESOT-1051 trial of its oral WEE1 inhibitor APR-1051.
This latest corporate update builds on the positive progress in ACESOT-1051 to date in which APR-1051 demonstrated early signs of single-agent activity along with a favorable tolerability profile in patients with difficult-to-treat cancers.
Next Clinical Update and Accelerating Enrollment
Aprea expects to report the next clinical data update from ACESOT-1051 at a medical meeting in the fourth quarter of 2026. Enrollment is accelerating ahead of this anticipated clinical catalyst, with the number of active clinical sites expanding from three to ten. Aprea expects enrollment to reach 6 to 10 patients per month by Q4 of 2026, potentially increasing the pace of clinical data generation. The Company also plans to broaden the development by advancing APR-1051 into combination regimens, expanding the current study to include arms enrolling HPV-positive head and neck squamous cell carcinoma and colorectal cancer in combination with standard-of-care therapies.
“Expanding enrollment and adding combination regimens in HPV positive head and neck cancer and colorectal cancer will broaden the clinical dataset as we advance development of ACESOT-1051,” said Gene Kennedy, M.D., Chief Medical Advisor of Aprea. “We look forward to sharing the next set of data from the trial at a medical meeting in the fourth quarter of this year,”
As previously announced, the Company is expanding enrollment to include at least 50 patients with uterine serous carcinoma or cyclin E-overexpressing, platinum-resistant ovarian cancer. Completion of dose escalation and backfill expansion is anticipated in the second quarter of 2027. This expansion is intended to further characterize the clinical activity of APR-1051 in biomarker-defined tumor populations with a mechanistic rationale for WEE1 inhibition.
Planned Combination Development
Aprea’s plans to evaluate APR-1051 in combination settings are supported by preclinical synergy observed in relevant disease models. In HPV-positive head and neck squamous cell carcinoma, the Company plans to combine APR-1051 with immune checkpoint therapy. In colorectal cancer, the Company plans to combine APR-1051 with standard-of-care chemotherapy.
The Company intends to advance dose levels that have already cleared safety review and shown single-agent activity into the planned combination regimens. This provides an appropriate starting point to establish the preliminary safety and preliminary efficacy of these regimens. In preclinical models, APR-1051 has demonstrated antitumor activity in combination with chemotherapy and with immuno-oncology agents, providing a rationale for the planned clinical combinations.
About ACESOT-1051 and Trial Design
ACESOT-1051 is a multi-center, open-label Phase 1 study evaluating oral, single-agent APR-1051 administered once daily in 28-day cycles. Part 1 is a dose escalation and dose backfill expansion of up to 100 patients, using accelerated titration at lower dose levels followed by a Bayesian optimal interval (BOIN) design. Part 2 is a dose selection optimization stage of up to 80 patients that will randomize patients 1:1 to two selected doses, to determine the recommended Phase 2 dose (RP2D).
Dose levels considered in the protocol range from 10 mg to 500 mg. Dose escalation is currently enrolling at the 300 mg cohort. Eligible patients are adults with advanced solid tumors harboring cancer-associated gene alterations, including uterine serous carcinoma regardless of biomarker status; cyclin E-overexpressing, platinum-resistant ovarian cancer (PROC); tumors harboring CCNE1, CCNE2, FBXW7, or PPP2R1A alterations; HPV-positive oropharyngeal, cervical, vaginal, or vulvar carcinoma; and KRAS- and TP53-mutated colorectal cancer.
The primary objectives are safety, dose-limiting toxicity, maximum tolerated or maximum administered dose, and RP2D. Secondary objectives include pharmacokinetics and antitumor activity assessed by RECIST/PCWG3.
The most recent update from the ACESOT-1051 trial was presented at the ASCO 2026 annual meeting; a copy of the poster can be found on the Aprea corporate website here.
For more information on ACESOT-1051, refer to ClinicalTrials.gov NCT06260514.
About Aprea Therapeutics
Aprea is a clinical-stage precision medicine oncology company focused on the discovery and development of targeted therapies for patients with biomarker-defined cancers. The Company is pioneering a new approach to treat cancer by exploiting vulnerabilities associated with cancer cell mutations. This approach was developed to kill tumors while minimizing the effect on normal, healthy cells. Aprea’s technology has potential applications across multiple cancer types, enabling it to target a range of tumors, including ovarian, endometrial, colorectal and head and neck squamous cell carcinoma. The Company’s lead programs are APR-1051, an oral, small-molecule inhibitor of WEE1 kinase, and ATRN-119, a small molecule ATR inhibitor, both in clinical development for solid tumor indications. For more information, please visit www.aprea.com.
The Company may use, and intends to use, its investor relations website at https://ir.aprea.com/ as a means of disclosing material nonpublic information and for complying with its disclosure obligations under Regulation FD.
Forward-Looking Statement
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Investor Contact:
Mike Moyer
LifeSci Advisors
mmoyer@lifesciadvisors.com
Media Contact:
Sean Naughton Ph.D.
Russo Partners, LLC
sean.naughton@russopartnersllc.com
(858) 717-2310
