Patient inclusion for babytam involve women with high-risk lesions or intraepithelial neoplasia, including ductal carcinoma in situ, lobular carcinoma in situ or atypical ductal hyperplasia. These are very high-risk lesions with a ten-fold risk increase of developing invasive breast cancer compared to the general population. We showed that low-dose tamoxifen, or babytam, can reduce the incidence of recurrence by 42% even after seven years from treatment cessation.
See, the other novelty of the trial, in addition to the dose, is the duration, which was only three years, and that's why we showed very low toxicity, because of the lower dose and the lower duration. These women seems to benefit from this intervention without side effects, but I think that implications can involve other categories. For instance, the NCCN recommends that babytam is given to women who don't tolerate the dose of 20 milligram, and rather than withdrawing the treatment, is better to have a lower dose even in the adjuvant setting, although we don't have the data in that context because we need to remember that tamoxifen is a generic drug, is very cheap. There's no commercial interest, and in the era of business-based medicine, it's very difficult to do big trials with this inexpensive drugs.
In our study, which included 500 women, we saw no signal for an increase toxicity compared with placebo, especially the serious adverse events were not significantly different between the two arms. We didn't see an excess of endometrial cancer, deep vein thrombosis, pulmonary emboli, coronary heart disease, bone fractures and other serious adverse events. The other thing is the patient-reported outcomes, especially the menopausal symptoms, which are the main reasons for treatment withdrawal in the clinical practice, hot flashes, pain during intercourse, other symptoms of menopause. These were not different between babytam and placebo except for less than an extra hot flash flashback per day during the three years where we measured every six months with menopausal and quality of life questionnaires, the onset of these patient-reported outcomes.
So the initial results were referring to a median followup of five years, and we showed a 52% reduction of recurrence and a 76% reduction of contralateral breast cancer, which opens the door for primary prevention. Now at 10 years, we see still a significant 42% reduction of recurrences with a nice carryover effect, and most of the recurrences are invasive up to 80%, stage I and ipsilateral. We didn't see any difference in the biology of the tumors between babytam and placebo, so there's no evidence that tamoxifen may select high-risk tumors.
I think our data at 10 years are mature to support a change in clinical practice so that women with high risk lesions, including DCIS, more importantly, and LCIS or ADH, can now receive five milligram per day or 10 milligram every other day of tamoxifen in their clinical practice. It is important to note that the five-milligram tablet does not exist on the market because this drug has little commercial interest. So because of the long half-life of the drug, we can use 10-milligram tablet given every other day as the same findings than the five milligram. We show that in an observational study.
