The Lidera trial is the first phase 3 trial of an oral SERD to read out in early stage breast cancer. It is a randomized trial of elacestrant given for five years compared to standard of care endocrine therapy which could be tamoxifen or the aromatase inhibitors anastrozole, letrozole or exemestane. Patients selected for this trial were at selected risk. It included ER positive patients, but also no ER negative patients if they had additional risk factors, including for tumors larger than one centimeter grade three, high genomic score or high Ki67...
The Lidera trial is the first phase 3 trial of an oral SERD to read out in early stage breast cancer. It is a randomized trial of elacestrant given for five years compared to standard of care endocrine therapy which could be tamoxifen or the aromatase inhibitors anastrozole, letrozole or exemestane. Patients selected for this trial were at selected risk. It included ER positive patients, but also no ER negative patients if they had additional risk factors, including for tumors larger than one centimeter grade three, high genomic score or high Ki67. For this, for ASCO 2026, we presented updated data on the menopausal status. We have previously demonstrated with just under three years of follow-up that the addition, that giving elacestrant instead of standard of care endocrine therapy significantly and in a meaningful way improves the invasive disease free survival with a hazard ratio of 0.7. We had also shown that distant recurrence-free interval was improved with a hazard ratio of 0.69. Here we have focused on menopausal status. 41% of patients in the oral trial were premenopausal. About 59% of patients were postmenopausal. In the premenopausal group, the majority of patients in the control arm received aromatase inhibitors. Two-thirds of patients, about one-third of patients received tamoxifen. Again, 69% of those patients on tamoxifen received ovarian function suppression. It was a very small percentage of patients who had tamoxifen alone. Comparing the two groups in the premenopausal setting, standard of care endocrine therapy or elacestrant was well balanced. Equally in the postmenopausal patients, well balanced between risk factors. But if you look at tamoxifen versus aromatase inhibitors in the premenopausal group, we saw slightly fewer patients with higher risk features. And that makes sense clinically, because clinicians would only choose tamoxifen normally in patients with a slightly more favorable prognosis. Now, if you look at the outcome for IDFS, they were consistent in the pre- and postmenopausal group. The hazard ratio for premenopausal patients was 0.65. For postmenopausal patients was 0.74. And the delta at about three years in the rates is about 3%. If you look at the distant recurrence-free interval, again, consistent benefit in the pre- and postmenopausal group. And we see a hazard ratio of 0.56 in the premenopausal group compared to 0.76 in the postmenopausal group. If you zoom in a little bit on the different treatments in the premenopausal group, we see a relatively similar benefit of elacestrant regardless of whether patients receive aromatase inhibitors or tamoxifen. That’s really reassuring to see. If we look at the safety profile, the safety profile seemed very comparable in the premenopausal group and the postmenopausal group. The dominant side effects were joint aches and hot flushes, but we also saw that patients treated with elacestrant had fewer switches to other endocrine therapy. With standard endocrine therapy, about 10% of patients decided to switch to an alternative therapy, whereas only at about 5% of patients on elacestrant switched to an alternative endocrine therapy. Equally, fewer patients discontinued hormone therapy, about 5% of patients with elacestrant compared to 8% of patients with aromatase inhibitors. The dominant factor for changes seems to have been in this trial, musculoskeletal pain, joint aches. And we, if you look at, we zoomed in a little bit more on that. If you look at all grades that looked relatively comparable between elacestrant and standard of care endocrine therapy, but really interesting if you look at the discontinuation rates due to musculoskeletal pain, that was about three times higher with aromatase inhibitors compared to elacestrant. With elacestrant, about 1.5% of patients stopped the treatment because of musculoskeletal pain. About 5% of patients with aromatase inhibitors stopped the treatment because of musculoskeletal pain. So in summary, at ASCO, we presented updated data that patients benefit regardless of the menopausal status in terms of IDFS and in terms of distant recurrence-free survival. The safety profile is well established now both in the pre and post menopausal group with advantages for elacestrant in terms of treatment discontinuations compared to standard of care endocrine therapy.
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