Elinzanetant Enhances QOL Despite Prior Endocrine Therapy in Breast Cancer

For patients with breast cancer experiencing sleep disturbances and menopause-related quality of life complications, elinzanetant (Lynkuet) demonstrated sustained improvements despite the type of endocrine therapy patients were prescribed, according to results from the phase 3 OASIS-4 subgroup analysis (NCT05587296) presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting.

Degree of sleep disturbance (PROMIS SD SF 8b total T-score) and menopause-related quality of life (MENQOL) were assessed using a variety of analysis tools. The type of endocrine therapy at baseline included tamoxifen, aromatase inhibitor, with gonadotropin-releasing hormone (GnRH), or without GnRH. The investigators noted that reductions in vasomotor symptom frequency and severity based on type of endocrine therapy have not been previously investigated.

The PROMIS SD SF 8b total T-score was evaluated by which endocrine therapy was received:

• Tamoxifen
  • Elinzanetant arm:Baseline mean of 61.0 (95% CI, 60.1-61.9), with a mean change from baseline to week 12 of –11.0 (95% CI, –12.3 to –9.7)
  • Placebo: Baseline mean, 60.5 (95% CI, 59.0-62.0); mean change from baseline to week 12, –4.3 (95% CI, –5.9 to –2.6)
• Aromatase Inhibitors
  • Elinzanetant arm: Baseline mean, 60.1 (95% CI, 59.0-61.2); mean change from baseline to week 12, –10.0 (95% CI, –11.4 to –8.7)
  • Placebo: Baseline mean, 61.1 (95% CI, 59.5-62.7); mean change from baseline to week 12, –3.8 (95% CI, –5.5 to –2.0)
• GnRH
  • Elinzanetant arm: Baseline mean, 60.4 (95% CI, 59.0-61.7); mean change from baseline to week 12, –10.4 (95% CI, –12.1 to –8.7)
  • Placebo: Baseline mean, 61.6 (95% CI, 59.5-63.7); mean change from baseline to week 12, –6.5 (95% CI, –8.7 to –4.2)
• No GnRH
  • Elinzanetant arm: Baseline mean, 60.7 (95% CI, 59.9-61.5); mean change from baseline to week 12, –10.6 (95% CI, –11.8 to –9.5)
  • Placebo: Baseline mean, 60.4 (95% CI, 59.1-61.7); mean change from baseline to week 12, –3.1 (95% CI, –4.5 to –1.7)

MENQOL

• Tamoxifen
  • Elinzanetant arm: Baseline mean, 4.7 (95% CI, 4.5-4.9); mean change from baseline to week 12, –1.4 (95% CI, –1.6 to –1.2)
  • Placebo: Baseline mean, 4.5 (95% CI, 4.2-4.7); mean change from baseline to week 12, –0.5 (95% CI, –0.7 to –0.3)
• Aromatase Inhibitors
  • Elinzanetant arm: Baseline mean, 5.0 (95% CI, 4.8-5.2); mean change from baseline to week 12, –1.2 (95% CI, –1.4 to –1.0)
  • Placebo: Baseline mean, 5.2 (95% CI, 4.9-5.5); mean change from baseline to week 12, –0.6 (95% CI, –1.0 to –0.3)
• GnRH
  • Elinzanetant arm: Baseline mean, 4.9 (95% CI, 4.6-5.1); mean change from baseline to week 12, –1.2 (95% CI, –1.5 to –1.0)
  • Placebo: Baseline mean, 4.9 (95% CI, 4.5-5.3); mean change from baseline to week 12, –0.6 (95% CI, –1.0 to –0.3)
• No GnRH
  • Elinzanetant arm: Baseline mean, 4.8 (95% CI, 4.7-5.0); mean change from baseline to week 12, –1.3 (95% CI, –1.5 to –1.2)
  • Placebo: Baseline mean, 4.7 (95% CI, 4.5-5.0); mean change from baseline to week 12, –0.5 (95% CI, –0.7 to –0.3)

A total of 474 patients were randomly assigned 2:1 to either the elinzanetant arm (n = 316) or the placebo arm (n = 158). Elinzanetant was given at 120 mg for up to 52 weeks, followed by an optional treatment extension. In the control arm, patients were given placebo for the first 12 weeks, followed by elinzanetant at 120 mg for the next 40 weeks.

Patients were included if they were 18 to 70 years old, receiving endocrine therapy for hormone receptor–positive breast cancer, and experiencing 35 or more moderate-to-severe hot flashes per week.

Overall, the duration of prior adjuvant therapies was 1.9 years. A total of 55.9% of patients were given tamoxifen and 15.2% had tamoxifen plus GnRH; 44.1% had aromatase inhibitors and 13.5% had aromatase inhibitors plus GnRH.

Patient demographics were characterized by endocrine therapy treatment given.

Tamoxifen

• Mean age: 50.4 years
• Duration of endocrine therapy: 2.1 years
• Race: White (87.2%)
• Mean weight: 71.0 kg
• Body mass index (BMI): 25.9 kg/m²
• Smoking history: Never (65.7%)

Aromatase Inhibitors

• Mean age: 51.9 years
• Duration of endocrine therapy: 1.8 years
• Race: White (89.5%)
• Weight: 72.9 kg
• BMI: 26.9 kg/m²
• Smoking history: Never (64.6%)

GnRH

• Mean age: 42.5 years
• Duration of endocrine therapy: 1.7 years
• Race: White (94.9%)
• Weight: 69.5 kg
• BMI: 25.4 kg/m²
• Smoking history: Never (66.2%)

No GnRH

• Mean age: 53.4 years
• Duration of endocrine therapy: 2.0 years
• Race: White (85.5%)
• Weight: 72.8 kg
• BMI: 26.7 kg/m²
• Smoking history: Never (64.8%)

In the presentation, the reported end points were degree of sleep disturbance, characterized by PROMIS SD SF 8b total T-score, and menopause-related quality of life assessed through level of bother across vasomotor, psychosocial, physical, and sexual domains, characterized by MENQOL total score.

Reference

Soares CN, Laapas K, Seitz C, et al. Effect of elinzanetant on sleep disturbance and aspects of quality of life in women with breast cancer experiencing vasomotor symptoms: OASIS-4 subgroup analysis by type of endocrine therapy. J Clin Oncol. 2026;44(suppl 16):512. doi:10.1200/JCO.2026.44.16_suppl.512