By VETTAPHARMA reporter – Derek Roche: The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) issued a positive opinion on May 22, 2026 recommending approval of camizestrant in combination with a CDK4/6 inhibitor for adult patients with estrogen receptor (ER)‑positive, HER2‑negative locally advanced or metastatic breast cancer who develop an emergent ESR1 mutation while receiving first‑line endocrine therapy plus a CDK4/6 inhibitor.
The recommendation is grounded in the SERENA‑6 Phase III trial, a global, double‑blind, randomized study that enrolled 315 patients identified by circulating tumour DNA (ctDNA) monitoring for emergent ESR1 mutations without radiographic progression. The planned interim analysis showed the camizestrant combination reduced the risk of disease progression or death by 56% (hazard ratio 0.44) versus standard‑of‑care aromatase inhibitor plus CDK4/6 inhibitor, with median progression‑free survival (PFS) of 16.0 months versus 9.2 months.
Key secondary outcomes continued to mature: PFS2 favored the camizestrant arm at 25.7 months versus 19.1 months (HR 0.63), and overall survival (OS) trended in favour of camizestrant (HR 0.87) with immature data at the interim cut. The trial used a ctDNA‑guided approach—routine blood testing every two to three months—to detect molecular resistance early and switch endocrine therapy before clinical progression, representing an adaptive strategy to extend first‑line benefit.
Safety findings were consistent with known profiles of the agents used; no new safety signals were identified and discontinuation rates were very low and similar between arms, according to the company statement. The combination’s tolerability supports the ctDNA‑guided switch strategy in a population already receiving CDK4/6 inhibitors.
If the European Commission endorses the CHMP opinion, camizestrant would become the first next‑generation oral selective estrogen receptor degrader (SERD) and complete ER antagonist approved in this specific ctDNA‑guided, emergent‑ESR1 setting in the EU. AstraZeneca noted camizestrant is already approved in the United Arab Emirates and Saudi Arabia for this indication and that regulatory submissions are under review in the U.S., Japan and other countries.
Clinically, the CHMP recommendation underscores a shift toward molecularly guided early intervention to delay progression and preserve quality of life in first‑line therapy. For patients, the approach promises earlier therapeutic change based on molecular resistance rather than waiting for radiographic progression. Commercially, approval would position camizestrant as a practice‑changing option that leverages ctDNA monitoring to personalise endocrine strategy and extend the utility of CDK4/6 combinations.
