The data that was presented at ASCO was, I think, a very exciting addition of data to the role of ribociclib in the hormone receptor positive metastatic breast cancer patients. And I think what was a resounding message was that we'd seen the data already from MONALEESA-3 and MONALEESA-7 for the overall patient population. So that was the all comers for each of those trials.
And it showed a significant benefit for the endocrine plus ribociclib arm in terms of progression-free survival as well as overall survival. So I always think one of the questions we ask as oncologists when we have a given patient in front of us trying to evaluate what the best treatment recommendations might be for that patient, is what to do with the variety of presentations of the hormone receptor positive metastatic breast cancer patients.
So we have a group that presents with very indolent bone only disease, and that tends to be a good proportion of patients represented in some of the clinical trials. And so this presentation actually wanted to carve out those patients with visceral metastasis. And I think those are definitely the more challenging patients, the patients that have more life-threatening disease. And the presentation looked at those populations from both MONALEESA-3 and MONALEESA-7. And they comprised about 60% of the patients in each of those two trials.
And when we looked at specifically those patients presenting with visceral metastasis, the majority, almost 50% each had lung metastasis and liver metastasis. And so these are disease recurrences in life sustaining organs. And traditionally, when patients had presented with that presentation and more hormone receptor positive, the thought for rescuing those patients, perhaps with chemotherapy, might be a treatment recommendation in reserving endocrine therapy for patients that had more indolent relapses, so maybe skin or soft tissue or bone disease.
So the question, I think, addressed by this presentation was looking and really being able to address specifically patients with visceral metastasis. And so in MONALEESA-3, which was a first and second line trial with a two to one randomization with fulvestrant and ribociclib versus fulvestrant alone, and MONALEESA-7, which truly is a stand alone in terms of looking at the premenopausal patient population with a nonsteroidal aromatase inhibitor in combination with ribociclib or ribociclib alone really looked at those patients that had this presentation with disease in their life threatening organs.
And the trial data was able to really show that these patients derived that same resounding evidence of clinical benefit of adding ribociclib, a CDK4/6 inhibitor to their endocrine therapy, having an advantage over just endocrine therapy alone, and showing that same message of improvement in the median progression-free survival, and that this also translated to an overall survival advantage in these patients who presented with visceral metastasis.
The other, I think, resounding message was that we didn't see increased toxicity. And so sometimes when we have disease in the liver, we do think about those patients being perhaps a little more challenged in metabolizing the drug or more susceptible to increased side effects. But the toxicity profile known and established for ribociclib was the same in these populations with a more life threatening disease occurrences in lung or liver. So I think as a clinician, now I think we have clear evidence that a patient who presents with disease in the liver or lung can equally be treated with an endocrine therapy approach in combination with a targeted therapy, such as ribociclib, and showing that those patients do derive a sustained benefit that really echoes the population of overall hormone receptor positive metastatic breast cancer patients enrolled in this trial.
So I think it gives a lot of clear confidence that when we had traditionally maybe a trigger to think about chemotherapy when a patient presents with a liver metastasis, that now we have data by this presentation to really show that those patients derive benefit. They don't have increased toxicity. And they also derive that overall survival advantage with approaching their disease recurrence with an endocrine treatment strategy in combination with targeted therapy with a CDK4/6 inhibitor. In this trial, ribociclib.
What questions still need to be answered?
The patients that present with hormone receptor positive metastatic breast cancer, I think, for the most part are receiving a CDK4/6 inhibitor such as ribociclib in combination with their endocrine therapy. I think the challenges are for us to understand what drives resistance. We see such a increase or doubling of the progression-free survival. And we see that now also translate as a surrogate for an overall survival advantage.
But if we can understand better what are the challenges in these patients who develop resistance or the patients that don't seem to derive that same long-term benefit-- trying to understand those mechanisms in place. I think also trying to look at now combinations or triplet therapies, perhaps an endocrine therapy with two targeted therapies to see if we can further build upon the data that we see at this point. And so those trials have been looked at.
Certainly with ribociclib, the mTOR inhibitor everolimus has been combined and actually did not show overlapping toxicity, but actually did show an advantage to the combination. And so whether it can reset the resistance pathways or mechanisms, I think, are something that we're looking at. We're looking at sequencing the CDK4/6 inhibitors and trying to see whether we can sustain that backbone or change the CDK4/6 inhibitor and maintain the endocrine therapy in looking forward to seeing how that data evolves over time. And some of those trials are in place.
And I think as we traditionally look at some of these advantages that we see in the metastatic breast cancer population is moving that bar forward, and looking at that in a neoadjuvant approach. And, traditionally, that's also been a platform where consideration for chemotherapy has had its stronghold. But we're stepping back now, and looking at these combinations of endocrine therapy with targeted therapy, really achieving those results.
And we know in the neoadjuvant setting, very few patients ever derived a complete pathologic response with chemotherapy. But now looking at this approach of considering ribociclib in combination with endocrine therapy or a CDK4/6 inhibitor or with endocrine therapy may be very advantageous to that patient population to avoid chemotherapy, and still achieve the goals that neoadjuvant therapy delivers for these patient populations.
And then, I think whether this will translate to a population in the adjuvant setting, I think, is something that we're also looking at. I think the adjuvant setting presents such challenges, though, in terms of really having to select the patient population to show those benefits. Because our adjuvant therapy delivers such good outcomes when we add a consideration of a targeted therapy to the standard of care. You really have to look at first delivering this, perhaps, to the higher at-risk group to show a window of opportunity and, again, trying to identify who would be best suited to derive the benefit in that disease setting.