This Week in Breast Cancer: Camizestrant Delay, Bria-IMT Data, Recurrence Test

From a closely watched FDA advisory panel vote to emerging immunotherapy survival signals and a promising liquid biopsy study, the past several days have been eventful in breast oncology. Here are 3 stories worth your attention:

1. FDA Extends Review Timeline for Camizestrant After Negative ODAC Vote

The FDA will extend the Prescription Drug User Fee Act (PDUFA) date to review additional data for the approval of camizestrant plus a CDK4/6 inhibitor in first-line hormone receptor (HR)–positive, HER2-negative advanced breast cancer with an emergent ESR1 mutation.¹ The data were requested to support the NDA, and included circulating tumor DNA (ctDNA) clearance data linked to longer-term efficacy outcomes. Those additional analyses are slated for presentation on June 2 at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting. Notably, the European Medicines Agency’s Committee for Medicinal Products for Human Use recommended camizestrant plus a CDK4/6 inhibitor for approval in the European Union on May 22, 2026, based on the phase 3 SERENA-6 (NCT04964934) data, underscoring the divergent regulatory paths this agent is navigating across jurisdictions.²

Camizestrant, an oral selective estrogen receptor degrader (SERD), received a 6-to-3 vote from the FDA's Oncologic Drugs Advisory Committee (ODAC) against the new drug application (NDA) for the agent in combination with a CDK4/6 inhibitor for patients with HR-positive, HER2-negative locally advanced or metastatic breast cancer with an emergent ESR1 mutation detected on ctDNA prior to radiographic progression.³

The April ODAC meeting evaluated a novel treatment-switching paradigm in which patients receiving an aromatase inhibitor (AI) and CDK4/6 inhibitor switched to camizestrant upon detection of an ESR1 mutation rather than at radiographic progression. Data presented at the 2025 ASCO Annual Meeting showed a median progression-free survival (PFS) of 16.0 months (95% CI, 12.7–18.2) with camizestrant plus a CDK4/6 inhibitor vs 9.2 months (95% CI, 7.2–9.5) in the control arm (HR, 0.44; 95% CI, 0.31–0.60; P <.00001).

Despite that substantial PFS benefit, the ODAC’s concern centered on the absence of overall survival (OS) data and questions about the trial's novel design.

2. Bria-IMT Continues to Show Safety in Pretreated Metastatic Breast Cancer

The Data Safety Monitoring Board (DSMB) has made a positive recommendation after the review of safety data from the phase 3 Bria-ABC trial (NCT06072612).⁴ In the Bria-ABC trial, Bria-IMT was administered in combination with an immune checkpoint inhibitor (CPI) in patients with metastatic breast cancer.

Additionally, the DSMB has recommended that the study continue without modifications.

In January, survival data from a phase 2 trial of Bria-IMT using the same formulation as the phase 3 Bria-ABC trial showed a median overall survival of 15.6 months in those who received a median of 6 prior therapies.⁵

Fast track designation was given to Bria-IMT in April 2022.⁶

3. ctDNA Blood Test Detects Breast Cancer Recurrence Nearly 4 Years Before Standard Methods

Researchers at Lund University have published validation data for a blood-based method, Pathlight, that measures ctDNA in patients with early breast cancer.⁷ The results, published in EMBO Molecular Medicine, suggest the test could substantially alter how clinicians monitor patients for relapse.

The study included 136 patients treated with chemotherapy and surgery for different types of breast cancer. Blood samples were collected at diagnosis, during treatment, shortly after surgery, and then regularly during follow-up for up to 6 years.

In patients who later developed metastatic disease, the blood test detected signs of recurrence a median of 13.8 months before the relapse became clinically visible. In some cases, this occurred nearly 4 years before current methods detected the disease. Additional signal highlights included: tumor DNA was detectable in approximately 90% of patients before treatment began; tumor DNA persisted after neoadjuvant chemotherapy in roughly 21% of patients; and tumor DNA levels did not decline clearly during treatment, which was strongly associated with high recurrence risk, in 13% of patients. The method provided more accurate prognostic information than pathological complete response (pCR).

References

1. FDA delays ruling on AstraZeneca’s breast cancer drug after negative adcomm vote. News release. Fierce Biotech. May 27, 2026. Accessed May 27, 2026. https://tinyurl.com/nhdcfnre
2. Camizestrant in combination with a CDK4/6 inhibitor recommended for approval in the EU by CHMP for 1st-line advanced ER-positive breast cancer. News release. AstraZeneca. May 22, 2026. Accessed May 27, 2026. https://tinyurl.com/ycj8wb73
3. April 30, 2026 meeting of the Oncologic Drug Advisory Committee (ODAC). YouTube. Accessed April 30, 2026. https://tinyurl.com/5cry64pu
4. BriaCell receives positive recommendation from Data Safety Monitoring Board (DSMB) for phase 3 study in metastatic breast cancer. News release. BriaCell Therapeutics. May 26, 2026. Accessed May 27, 2026. https://tinyurl.com/mrstcuph
5. BriaCell highlights extended >18-47 months survival in phase 2 metastatic breast cancer patients. News release. BriaCell Therapeutics. January 27, 2026. Accessed May 27, 2026. https://tinyurl.com/ms8d4nrj
6. BriaCell received FDA fast track approval for targeted breast cancer immunotherapy. News Release. BriaCell Therapeutics. April 13, 2022. Accessed May 27, 2026. https://bit.ly/3M1kWlC
7. Blood test detects early signs of breast cancer recurrence. News release. Lund University. May 26, 2026. Accessed May 27, 2026. https://tinyurl.com/27bajx56