Milan Consensus Endpoints for Bladder Preservation in MIBC

Guests Dr. Andrea Necchi, Dr. Ashish Kamat and host Dr. Davide Soldato discuss JCO article "End Points for the Next-Generation Bladder-Sparing Perioperative Trials for Patients With Muscle-Invasive Bladder Cancer," focusing on the evolving treatment landscape of MIBC (muscle-invasive bladder cancer) and the need to properly design novel trials investigating non-operative management while including the incorporation of biomarkers and patient perspectives in clinical trials.

TRANSCRIPT

The disclosures for guests on this podcast can be found in the show notes.

Dr. Davide Soldato: Hello and welcome to JCO After Hours, the podcast where we sit down with authors from some of the latest articles published in the Journal of Clinical Oncology. I am your host, Dr. Davide Soldato, medical oncologist at Ospedale San Martino in Genoa, Italy.

Today we are joined by JCO authors Andrea Necchi, Associate Professor of Medical Oncology at University San Raffaele and Medical Oncology at Ospedale San Raffaele in Milan, Italy, and Ashish Kamat, Professor of Urologic Oncology and Cancer Research at University of Texas MD Anderson Cancer Center. Both Professor Necchi and Professor Kamat are internationally recognized experts in the field of genitourinary malignancy and particularly in bladder cancer.

Today we will be discussing the article titled "Endpoints for the Next Generation Bladder-Sparing Perioperative Trials for Patients with Muscle-Invasive Bladder Cancer."

So thank you for speaking with us, Professor Necchi and Professor Kamat.

Dr. Andrea Necchi: Thank you, Davide, and thank you JCO for the opportunity.

Dr. Ashish Kamat: Yeah, absolutely. It is a great honor and privilege to be discussing this very important article with you. So thank you for the invitation.

Dr. Davide Soldato: The article that you just published in JCO reports the results of a consensus meeting that was held among experts in the field of genitourinary malignancy and particularly for bladder cancer. So the objective was really to define endpoints for a novel generation of trials among patients diagnosed with muscle-invasive bladder cancer. So my first question would be: what is the change in clinical practice and in clinical evidence that we have right now that prompted the start of such consensus in 2025?

Dr. Andrea Necchi: So, we are living so many changes in the treatment paradigm of patients with muscle-invasive bladder cancer. In general, patients diagnosed with bladder cancer or urothelial cancer today, thanks to the advent of immunotherapy or immunotherapy combinations, and today thanks to the advent of novel antibody-drug conjugates like enfortumab vedotin in combination with immunotherapy that are actually changing the landscape of treatment of patients with metastatic disease and also are entering quite fast into the treatment paradigm of patients with organ-confined disease with a lot of clinical trials testing these combination therapies, neoadjuvantly or adjuvantly, before or after radical cystectomy.

Having said that, by potentiating the efficacy of systemic therapy, an increasing number of patients that receive neoadjuvant therapy of any kind, at a certain point in time, result to have achieved a deep response to systemic therapy, evaluated radiologically with conventional imaging, CT scan or MRI, or with cystoscopy or with other urology-based techniques, urinary cytology, and so. And based on the fact that they achieve a complete response, so no residual viable disease after systemic therapy, they raise concern about the fact that they have to undergo surgery like radical cystectomy that is quite impactful for their quality of life and for the future of their lives after the surgery. So the point that the patients are raising, and the patients are raising this point, is primarily due to the efficacy of systemic therapy.

And we have seen so many cases fortunately achieving a deep response. So the question about what to do with the patient that at a certain point, at the start with the commitment to radical cystectomy, but at a certain point in time change their mind towards something else if possible, depending on the fact that they have achieved a deep response, is something that is a question and is a need to which we have to provide data, information, and guidance in general to the patients.

Dr. Davide Soldato: If we look at the population that the recommendations were formulated for, we are mainly speaking about patients who would be fit for cystectomy, and this is a very distinct population compared to those who are not fit for cystectomy, both from a medical oncology point of view but also from a urologic point of view in terms of surgery. So, can you explain a little bit to our listeners why you think that this distinction is critical and why you developed this recommendation especially for this population?

Dr. Ashish Kamat: That is a very important distinction that you made. To build upon what Professor Necchi mentioned earlier, this question that we get from patients after neoadjuvant therapy or systemic therapy is not a new question. It has been something that they have been asking us for the last 20 or 30 years. "Do I really need to have my bladder taken out?" And patients who are especially not fit for surgery will sometimes say, "Do I need to have my bladder taken out? And if I cannot have my bladder taken out, am I going to just not have anything done?" Because the eligibility for radical cystectomy is also a moving target.

Over the years with improvement in surgical technique, improvement in perioperative therapy, ERAS protocols, et cetera, it is really unusual for us to deny a patient the opportunity to have major surgery unless clearly they have very significant comorbid conditions. So I think this endeavor is more broadly encompassing of the patient population than what was evident in previous years.

And I really want to give a shout out to Professor Necchi because what we did was, as part of the International Bladder Cancer Group and Professor Necchi is an integral part of the scientific advisory board, we broached this topic broadly during one of our discussions. And of course, Andrea always does this, he picks on a topic and then he says, "Okay, we need to discuss this really in detail," put together a multinational, multicenter collaborative group, but the driving force was our patients. Because our patients are constantly asking, "Do I need to lose my organ? Do I need to have radiation therapy?" which again, also, has a lot of side effects.

So this was really to answer the question in today's day and age as to do we need to do local consolidation, and if so, in what way? It is not a new question, but we have newer therapies, newer technology, and better ways to answer this. So it is a much needed question that needs to be answered. And I think the distinction between non-surgical candidates and surgical candidates is a little bit blurred in today's day and age.

Dr. Davide Soldato: What about the eligibility, for example, for cisplatin-based chemotherapy? Because I think that that is a very fundamental part of this type of strategy that we apply to patients with muscle-invasive bladder cancer. So we know that there are some caveats for proposing such treatment. And also this population was specifically defined inside this recommendation.

Dr. Andrea Necchi: I think that the focus of our work is just to analyze what is happening after any type of systemic therapy the patient may get neoadjuvantly. So it is not actually a question of treatment eligibility or including cisplatin eligibility. This is an old question of today's practice and clinical trials. But regardless of what the patient received neoadjuvantly, the point that we have addressed in our consensus meeting was what to do next as a further step after systemic therapy or not.

So basically we are- the consensus guidance includes all-comers, so patients to get any type of systemic therapy. So really non-selected based on specific features that determine a special eligibility to a special or a particular therapy. But an all-comer approach is always the winning approach for the translation to be in practice, an all-comer approach just focusing on what has happened after treatment and that we are assessing by the use of conventional imaging, MRI or CT, cystoscopy, urinary cytology, and trying to merge all together this information, all these features in a unique, shared, reliable definition of clinical complete response that could be used as a biomarker for the selection of newer therapies instead of pathological response that has been historically used, and maybe surrogate for the outcome, the long-term outcome and survival of these patients.

Dr. Davide Soldato: A very specific point of the consensus was actually the definition of clinical complete response. As you were saying, this is actually a combination of several parameters including urinary cytology, the use of cross-sectional imaging, for example CT scan, but also the evaluation in cystoscopy of the bladder. Do you foresee any potential problems when applying this type of recommendation, not inside clinical trials, but in the context of routine clinical practice?

Dr. Ashish Kamat: Absolutely. And that was the whole reason we had this consensus meeting. What happens nowadays in daily practice, and we see this every day at our center, we see patients referred to us. This definition or this sort of attempt to define clinical complete response is an ongoing issue. And urologists, medical oncologists, radiation oncologists are always looking to see, does my patient have a complete response? That definition and those paradigms have changed and evolved over the years.

The FDA had a workshop many years ago looking at this very question. And it was to address the proposal that complete clinical response, which is a clinical definition, a clinical state, does this correlate with pathologic response? And with the technology and the systemic therapies we had then, the answer was 'no'. In fact, more patients got recurrent disease than did not get recurrent disease. And that is why, of course in the paper we mention the trials that looked at this question, the trials that evolved around this question.

And I think the distinction between a clinical trial and daily practice is extremely important when we are looking at this definition per se. Because essentially what happens with this issue is that if the patient is not appropriately counseled, and if the physician does not do the appropriate clinical complete response assessment as Professor Necchi mentioned, right, cystoscopy, cytology, imaging, use of markers that are still in evolvement, we risk doing harm to the patient. So we caution in the paper too that this definition is not ready for prime time use. It is something that needs to be studied. It is a rigorous definition and currently we are recommending it for clinical trials. I am sure eventually it will trickle down into clinical practice, but that guidance was not the purpose of this consensus meeting.

Dr. Davide Soldato: There are several parameters that are potentially evolving and could potentially enter inside of clinical practice. For example, you mentioned pelvic MRI and we have now very specific criteria, the VI-RADS criteria, we're able actually to diagnose and also to provide information. So along with these novel imaging techniques, we also know that there are novel biomarkers that could be explored, for example ctDNA and urinary DNA. So what I was wondering is, why were not these included inside the definition that you provide for clinical complete response? And do you think that, as we are designing these trials to potentially spare cystectomy for this patient, we should include these biomarkers very early so that we can actually provide better stratification for our patients and really propose this type of cystectomy-sparing strategy only to those where we are very confident that we have obtained a clinical complete response?

Dr. Andrea Necchi: I would say you have just to wait. So a follow-up is ongoing and hard work is ongoing. At the time we met, at the time we established the meeting in mid-December last year, we had no information on the ctDNA data from major trials, with only a few exceptions. So we were just at the beginning of a story that was more than likely to change but still without numbers and without data from clinical trials. Now in just nine months or 10 months time, we have accumulated important data and newer data will be presented during just a few weeks and a few days regarding the ctDNA, circulating tumor DNA in particular, as a prognostic marker assessed baseline or assessed after neoadjuvant therapy.

So the point is certainly well made and ctDNA is certainly well shaped to be incorporated in a future definition of clinical complete response. But you have to consider the fact that most of the data that we are accumulating related to ctDNA are about the post-cystectomy field or the metastatic field. So regarding neoadjuvant therapy, you know, we have neoadjuvant therapy in the context of bladder-sparing approach, basically we have no information.

And the point that is emerging in our daily practice when using these biomarkers or in clinical trials, and the impression in general, is that it is a very strong biomarker associated with survival, but we absolutely do not know what is the performance of the test in the prediction of superficial bladder relapses, high-grade pTa relapse in the bladder that is left untouched in the patient. We are considering, and maybe it will be just a matter of further discussion, not just what is happening within the immediate endpoint of clinical CR, but also what is happening later with other survival endpoints.

And for example, when looking at the type of events that we may see in this kind of bladder-sparing approaches, most of the events, also in the trials that have been published including the RETAIN study published in JCO, most of the events are related to superficial high-grade superficial non-muscle invasive relapses. So the ability to predict these types of events with ctDNA is completely unknown. Maybe, maybe other liquid biomarkers like urinary tumor DNA, utDNA, could be a bit better shaped in the prediction of this kind of events, you know. But we have still to build the story.

So the question is good. The answer is yes, we will likely, more than likely incorporate liquid biomarkers in the definition, but we have to wait at least more data and more robust data in order to translate this information in routine practice, you know. Another consensus meeting is organized by IBCG and the same folks for November. This meeting will be primarily focused on the liquid biomarkers, the interpretation and use and approval and so of liquid biomarkers including bladder cancer. And we will likely be able to address all these, most of these open issues, so most of these points in the next meetings.

Dr. Davide Soldato: In the consensus you say that probably clinical complete response is now ready to be included in early phase trials, so actually to test what is the efficacy of the regimens that is being evaluated inside of these trials. But you actually do very in-depth work of defining what are the most appropriate endpoints for later phase trials. So to be very specific, the phase three registrational trials that bring new regimens inside of this space. So I just wanted to hear a little bit about what was the definition for event-free survival, which you define as the most appropriate one for this type of trials. And as you were mentioning before, Professor Necchi, there is a very specific interest on the type of events that we observe, especially when we look at these superficial relapses inside of the bladder. So was this a very urgent matter of debate as we define which type of events should actually trigger event-free survival? And did you make a very thoughtful decision about why using this type of endpoint instead of others, for example metastasis-free survival?

Dr. Ashish Kamat: Yeah, this was a matter of intense debate as you might imagine. And again, this is a moving target. So as Professor Necchi mentioned, we tend to partner with each other, our organizations, on having definitions of clinical complete response, biomarker, retreats, and then using that as a marker, and you might imagine this definition of what is appropriate event-free survival, what events matter to the patient, is something we have been talking about for two years. It was not just something that came up at the retreat. But at the retreat there was intense discussion.

One of the things that we talked about was bladder-intact event-free survival because we are trying to spare the patient's bladder. And do we count bladder-intact event-free survival as something that is relevant? The patient advocates absolutely liked that, right? They wanted that. But then we also learned from some of the studies, for example from the RETAIN study, that the non-muscle invasive recurrences can actually lead to metastatic disease. It is not as benign when you have a patient with muscle-invasive bladder cancer that then develops a non-invasive tumor because maybe there is cancer growing underneath the surface that we don't detect when we look in the bladder.

So a lot of those discussions were held, debated. It was a consensus. I have to say it was not 100% agreement on that particular definition, but it was broad consensus. And Andrea, do you want to clarify a little bit as to how we came about that consensus? Because I think this is a very important point we need to make.

Dr. Andrea Necchi: We focused on a bit different definition of BI-EFS, Bladder-Intact Event-Free survival. Just stating EFS as an all-inclusive parameter including all type of high-grade relapse or progression or death that may happen to the patient. So that we were counting high-grade pTa, pT1, CIS relapses to the bladder and of course more deeper involvement in the muscle layer and so, and metastatic disease as a relapse. But the point is that as compared to the classical bladder-intact EFS definition of chemoradiation bladder-sparing approaches that is including muscle-invasive relapses only or death as events, we tried to be as inclusive as possible in order to be as much conservative as possible and to raise as higher the bar as possible for the success.

And this is actually what the patients are asking us. So they are asking, "Okay, I can save my bladder, sparing radical cystectomy, but at which cost?" So in order to provide an answer, we have to be very, very cautious and be on the right shape, on the right position to say, "Okay, we have accomplished the most, the safest points, you know, by which you can proceed with the bladder-sparing." This is the first point.

The other point is related to the MFS, metastasis-free survival that you have mentioned. For sure, it was recognized as a very important point for sure. But in the discussion was clear that our focus was in saving patients, curing the patient, and saving the bladder. Any single event, superficial event that may occur in the bladder-saving approaches of this kind may expose the patient to an extra risk of developing distant metastases, as it happened for example in the RETAIN study. So EFS defined as we have agreed and published, is actually a way of including or anticipating in a safest position the MFS. Because most or if not the entirety of the events of metastasis development in patients undergoing bladder-sparing after neoadjuvant systemic therapy were preceded by a superficial phase of disease relapse, you know.

So I remember very, very few, or we can count just on the finger of one hand, the cases that have been reported in the literature developing de novo metastatic disease in the similar bladder-sparing approaches, in particular when using a maintenance immunotherapy strategy, you know, after they reach TURBT. So this is the reason why with all the limitation that Ashish has mentioned, with all the uncertainties that are still there, the nervousness that is still there, EFS, as defined in the protocol, as put in the paper, is to us at the moment is the safest way to use a primary endpoint in potentially registration trials of this kind with perioperative systemic therapy and response-adapted surgery.

Dr. Ashish Kamat: And David, just to be absolutely clear for our listeners, right, so what was the event-free survival that we defined? Essentially it was a very inclusive definition. Event was defined as high-grade tumor persistence, recurrence, or progression during or after perioperative therapy, and receipt of any additional standard of care treatment including radical cystectomy, radiotherapy or even intravesical therapy. So this was done at the behest of our patient advocates because we really wanted to make a very robust definition that could be utilized appropriately as an adequate primary endpoint for both early and late phase bladder preservation trials.

Dr. Davide Soldato: I think that it really highlights one of the points that I liked the most about this consensus is that it really incorporated the patient vision and a sort of shared decision making process when we are deciding how we want to design these trials that will explore this bladder-sparing surgery.

And Professor Necchi mentioned something that I think will be also a very interesting question for trials that will be developed considering the activity of this combination that we are seeing right now, which is maintenance. Because right now our approach in the few cases where patients do not do any type of treatments after an induction with neoadjuvant treatments is basically represented by observation. So I was wondering if you think that the field will actually evolve to a sort of maintenance strategy even in patients that will achieve a complete clinical response?

Dr. Andrea Necchi: We just mentioned briefly in the paper, this is a very important point that was touched during the discussion, and in particular was raised and discussed by FDA people participating in the meeting. And when looking at the data from the trials that were available and are still available thus far, we could provide a suggestion that maintenance immune therapy is the preferred approach in this kind of approach as it currently stands, as the data currently stand. Because the cleanest data towards the successful part of this journey is related to the studies that provided a kind of maintenance therapy, like the study with nivolumab or the RETAIN-2 study with maintenance immune therapy instead of RETAIN study that was just stopping treatment until surgery with MVAC chemotherapy.

So in general the impression is that maintenance therapy may help in reducing the type of events, including the events that we incorporate in the EFS definition that we mentioned in the paper. The point that you mentioned is very important because on the other side we have a problem, a big problem of affordability and cost of the treatment. The de-escalation trials are an urgent need and represent a call for the studies. Unfortunately, as you mentioned, this is something that moves beyond the possibilities of this type of consensus because we don't have data and we have to accumulate data from clinical trials prior to saying, "Okay, certain patients could de-escalate therapy and stop therapy and some other not." So we are still at the very beginning. So we can do- we can discuss about this in the radical cystectomy paradigm but not in the bladder-sparing paradigm, you know. But this is for sure a point, a discussion point that will be taken, pretty well taken in one year or two year projection.

Dr. Davide Soldato: I was wondering if in the consensus, considering that patient advocates and patient associations were also involved, did you decide to actually suggest the inclusion of patient-reported outcomes or the evaluation of shared decision-making in the development of this trial really as endpoints that should matter as much or as much as possible as event-free survival and clinical complete response?

Dr. Ashish Kamat: Oh yeah, absolutely. We had patient advocates, we had the World Bladder Cancer Patient Coalition, Bladder Cancer Advocacy Network, patient representatives. And we always consider this. Shared decision-making is actually the impetus behind why these efforts have been launched, right? So it is the shared decision-making that is very, very important. It is the driving force behind what we do. And it is worth noting, for example, for the design of such studies, regulatory agencies consider response-based endpoints or overall survival as primary endpoints. But the patient advocates consider quality of life to be just as important, if not more important sometimes than overall survival numbers. Because patient advocates will say, "Well if I live longer but I'm miserable living longer, yes that works for regulatory agencies but doesn't work for us." So PROs clearly are very, very important. And, in fact, we just literally had a meeting in Houston, the IBCG meeting where PROs were a main point of what we discussed. So incorporating PROs in everything we do, not just this but everything we do, Dr. Necchi, myself, everybody involved in these fields realizes it is very, very important. So absolutely.

Dr. Davide Soldato: I want to thank again Professor Necchi and Professor Kamat for joining us today.

Dr. Andrea Necchi: Thank you.

Dr. Ashish Kamat: It is our pleasure.

Dr. Davide Soldato: Thanks again and we appreciate you sharing more on your JCO article titled "Endpoints for the Next Generation Bladder-Sparing Perioperative Trials for Patients with Muscle-Invasive Bladder Cancer."

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