LGND - Ligand Sermonix breast cancer drug lasofoxifene fails to show 'statistical significance' in trial

Sermonix Pharmaceuticals said lasofoxifene showed anti-tumor activity but could not reach statistical significance in a phase 2 trial in patients with a type of breast cancer.

Privately held Sermonix had licensed lasofoxifene — a nonsteroidal selective estrogen receptor modulator (SERM) — from Ligand Pharmaceuticals ( NASDAQ: LGND ).

The phase 2 study, dubbed ELAINE 1, evaluated oral lasofoxifene against AstraZeneca's ( NASDAQ: AZN ) Faslodex (fulvestrant) to treat postmenopausal women with ESR1-mutated metastatic breast cancer who have progression on an aromatase inhibitor ((Al)) in combination with a CDK4/6 inhibitor therapies.

Progression-free survival (PFS - length of time during/after therapy a patient lives with the disease without it getting worse) was the main goal of the study.

Median PFS for lasofoxifene was 6.04 months, compared to 4.04 months for fulvestrant, the company said in a Sept. 13 press release.

Clinical benefit rate — defined as percentage of all people with a complete or partial response; or stable disease for ?24 weeks — was 36.5% for lasofoxifene, compared to 21.6% for fulvestrant.

The company added that objective response rate was 13.2% for lasofoxifene versus 2.9% for fulvestrant.

Sermonix noted that while not reaching statistical significance in this 103-patient study, all endpoints numerically favored lasofoxifene.

"Lasofoxifene following endocrine/CDK4/6 inhibitor therapies continues to be studied and we anticipate efficacy will be confirmed in a larger clinical study. Sermonix is planning a Phase 3 registrational combination study based on these results as well as encouraging efficacy and safety demonstrated in the ELAINE 2 study of lasofoxifene and abemaciclib reported at this year’s ASCO annual meeting," said Sermonix Founder and CEO David Portman.

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