AstraZeneca Highlights Significant Gains Across Three Major Cancer Trials At ASCO

AstraZeneca Plc AZN on Monday released results from three Phase 3 clinical trials at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting: DESTINY-Breast09, MATTERHORN, and SERENA-6.

DESTINY-Breast09 trial

In the DESTINY-Breast09 trial, Enhertu (trastuzumab deruxtecan) combined with pertuzumab was evaluated as a first-line treatment for HER2-positive metastatic breast cancer, compared to a standard regimen of a taxane, trastuzumab, and pertuzumab (THP).

Topline data were shared in April.

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Results indicated that the Enhertu combination reduced the risk of disease progression or death by 44%. Median progression-free survival (PFS) reached 40.7 months with the Enhertu regimen versus 26.9 months for THP, a benefit observed across patient subgroups.

Investigator-assessed median PFS was 40.7 months for the Enhertu arm and 20.7 months for THP. The confirmed objective response rate was 85.1% for the Enhertu combination and 78.6% for THP, with 58 complete responses in the Enhertu group compared to 33 with THP.

The median duration of response was 39.2 months for the Enhertu combination and 26.4 months for THP. Overall survival data was not yet mature, though an early trend favored the Enhertu combination.

MATTERHORN trial

The MATTERHORN trial assessed Imfinzi (durvalumab) with standard FLOT (fluorouracil, leucovorin, oxaliplatin, and docetaxel) chemotherapy as a perioperative treatment for resectable, early-stage, and locally advanced gastric and gastroesophageal junction (GEJ) cancers, compared to chemotherapy alone.

Topline data were released in March.

A planned interim analysis showed that the Imfinzi-based regimen led to a 29% reduction in the risk of disease progression, recurrence, or death.

Median event-free survival (EFS) was not reached in the Imfinzi arm, compared to 32.8 months in the chemotherapy-alone arm. The estimated 24-month EFS rate was 67.4% for the Imfinzi regimen and 58.5% for chemotherapy alone.

A trend towards improved overall survival was noted for the Imfinzi-based regimen, with formal assessment to follow.

SERENA-6 trial

The SERENA-6 trial investigated camizestrant combined with a cyclin-dependent kinase (CDK) 4/6 inhibitor (palbociclib, ribociclib or abemaciclib) in patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer whose tumors developed an ESR1 mutation during first-line treatment with an aromatase inhibitor (AI) and a CDK4/6 inhibitor.

Topline data were shared in February.

The trial compared switching to the camizestrant combination against continuing the AI plus CDK4/6 inhibitor. The camizestrant combination reduced the risk of disease progression or death by 56%.

Median PFS was 16.0 months for patients who switched, versus 9.2 months for those continuing the AI combination. The median time to deterioration of global health status was 23.0 months for the camizestrant arm and 6.4 months for the AI combination arm.

While data for time to second disease progression and overall survival were immature, a trend favored the camizestrant combination for PFS2.

Price Action: AZN stock is trading lower by 0.95% at $72.14 at last check Monday.

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