RADIANT: Pre-op Radiation With Abemaciclib and Letrozole

What this trial studies

This phase 1b study investigates the safety and feasibility of combining pre-operative radiation therapy with Cyclin-Dependent Kinase 4 (CDK4/6) inhibitors in participants with hormone receptor positive/HER2 negative (HR+/HER2-) breast cancer. The study aims to assess the benefits of concurrent use of these treatments in a specific participant population, focusing on their safety and tolerability. The hypothesis is that the combination therapy will be well-tolerated, providing valuable insights into its effectiveness for future clinical applications.

Conditions in scope

• Breast Cancer

Interventions

• Abemaciclib (Drug) — 150mg twice a day for 3 cycles prior to radiation.
• Letrozole (Drug) — Letrozole 2.5mg daily

Who can join

Women only · Ages 60 Years and up

Inclusion criteria

• Histologically and/or cytologically confirmed diagnosis of invasive (ductal, lobular or mixed histology), Clinically inapparent tumor that is not palpable. (cT1-T2N0)disease. Minimum tumor size of 1.5 cm
• Expression of ER or progesterone receptors (PR)and negative expression of HER2 per American Society of Clinical Oncology, (ASCO) Common Alerting Protocol (CAP) guidelines
• Oncotype diagnosis (DX) Breast Recurrence score of less than 25 on core biopsy specimen
• Post-menopausal status defined:
• age \<60 with amenorrhea for at least 12 months in the absence of prior chemotherapy, tamoxifen, toremifene, or ovarian suppression and estradiol and FSH (follicle stimulating hormone) in postmenopausal range.
• No clinical suspicion of metastasis disease
• Eastern Cooperative Oncology Group (ECOG) performance status of follicle stimulating hormone (PFS) ≤2
• Eligible to undergo surgery, either lumpectomy or mastectomy for local treatment of the breast cancer

Exclusion criteria

• History of ipsilateral breast cancer
• Prior treatment with CDK4/6 inhibitors or aromatase inhibitors
• History of chest wall or ipsilateral breast radiation
• Inflammatory breast cancer
• Needs neoadjuvant chemotherapy
• Presence of distant metastatic disease
• Contraindication for surgery
• Uncontrolled hypertension (systolic blood pressure \>190 mm Hg or diastolic blood pressure \>100 mm Hg)

Eligibility wording paraphrased from the public record. View the full criteria on ClinicalTrials.gov before contacting a site.

Where it’s happening

Status & timeline

• Overall status: Recruiting
• Study type: Interventional
• Phase: PHASE1
• Start date: 2024-08-22
• Primary completion: 2026-09-30
• Last update posted: 2025-11-14
• First posted: 2023-11-18

Sponsor & contact

Lead sponsor: Mridula George, MD (Other)

For trial site contact information, use the official record at ClinicalTrials.gov. Contact details change frequently and the public record is the source of truth.

Outcome measures

Primary outcomes

• Safety and tolerability of the combination of abemaciclib and radiation as assessed by adverse events (AEs). Using Common Terminology Criteria for Adverse Events (CTCAE v5.0) (From baseline, every six months, to five years)
  The outcome measure aims to characterize the safety and toxicity profile of the study treatment by assessing the occurrence and severity of adverse events (AEs) as measured using the CTCAE v.5. The CTCAE v.5 utilizes a standardized grading scale to assess the severity of adverse events. The scale consists of grades ranging from 1 to 5, with each grade corresponding…

Related ClearedRx care

If you’re reading this trial because you have menopause symptoms now, you don’t have to wait for a trial to access evidence-based care. ClearedRx prescribes the same FDA-approved and compounded HRT products that have been studied in trials like this one for decades.