Advanced Clear Cell RCC: AE Profile of First-Line Combination Therapies

Transcript:

Brian I. Rini, MD:Let’s talk about toxicity of these regimens. They each have their toxicity, and as I mentioned, one of the reasons that maybe I don’t give more ipilimumab-nivolumab is that fear of ipilimumab toxicity. Because if you have a bad TKI [tyrosine kinase inhibitor]-based toxicity, that might be like bad diarrhea and anorexia, and you stop, and it gets better. Transaminitis, and you stop, and it generally gets better within days, maybe weeks. If you have a bad ipilimumab toxicity, that can be life-threatening. We’re all scarred by our worst experiences somewhat. I guess maybe the question, Betsy, I’ll start with you, is are you not giving more ipilimumab-nivolumab for the reasons that I may be alluding to, that I’m a little scared of that up-front toxicity and actually shortening a patient’s life instead of lengthening it?

Elizabeth Plimack, MD, MS: For sure. I think a large percentage of patients who get ipilimumab-nivolumab had to be admitted for high-dose steroids and then usually have to stop treatment. Then they’re on to just TKI alone. So that scenario is pretty common with ipilimumab and nivolumab. So it is one of the deterrents for me. Honestly, the reason I don’t turn to it more is because I truly believe the long-term data with the IO [immune-oncology]-TKI combinations is going to match that with ipilimumab-nivolumab when looked at appropriately. I don’t think, it’s not as durable and that’s colored by my clinical experience. We’ve done a lot with these drugs over the years. So toxicity and the fact that I don’t think you give up efficacy by steering away from ipilimumab and nivolumab.

Brian I. Rini, MD:Let me channel some of our colleagues now. So ipilimumab-nivolumab has a 30% tail to PFS [progression-free survival] curves.

Elizabeth Plimack, MD, MS: Estimated.

Brian I. Rini, MD:Axitinib-pembrolizumab, presented today, was 18.4% or something.

Brian I. Rini, MD:I know we’re comparing subsets and all the caveats and statistics, and luckily there are no statisticians on the panel, but that’s going to happen. Those ipilimumab-nivolumab folks can say, “Wait a minute, it’s 30%, not 20%.”

Elizabeth Plimack, MD, MS: But the 30% is an estimate with an awful lot of censoring. Those curves are frozen in time. So the ipilimumab-nivolumab data, there’s 7-plus years of follow-up for the last patient enrolled on that study. That estimate will never change. With the axitinib and pembrolizumab, we’re seeing constant change because they’re actually continuing to collect data on these patients.

Brian I. Rini, MD: You think it’s a bit of a, I don’t want to say, methodologic issue?

Elizabeth Plimack, MD, MS: I do. I think that’s why that curve is flat, flat, flat and will be forever, because they’ve lost those patients to follow-up. You can look at the numbers at the bottom and how quickly they drop off; we can’t confirm those patients are alive and progression-free. The other thing is the survival, which is a little easier to track, those curves continue to go down. What are people dying of if they’re not progressing but they’re still dying? My guess is it is uncaptured progression. It’s a guess, but it’s filling in a gap of missing data. And related to having participated in all these studies and understanding how the data collection was different. So it’s nuanced.

Brian I. Rini, MD:I think, and maybe the larger point is, long-term follow-up of trials is super important.

Elizabeth Plimack, MD, MS: Super important.

Brian I. Rini, MD:We get all excited about initial results and ASCO [the American Society of Clinical Oncology meeting], plenary [sessions], and all these impact publications, which is great, but in the clinic it’s really important to know how to follow people and how long.

Elizabeth Plimack, MD, MS: We’re making decisions based on those at the front line, based on data that we anticipate for that patient in front of us 5, 10 years from now. So yes, it’s important.

Brian I. Rini, MD:How much ipilimumab-nivolumab do you use?

Eric Jonasch, MD: I use it probably in [approximately] one-third of my patients.

Brian I. Rini, MD:Not more [patients] because of toxicity?

Eric Jonasch, MD: No. Because I don’t think it’s appropriate for most favorable risk patients, I don’t think it‘s appropriate. Then there‘s the intermediate poor risk groups where I think they need to have a faster response. But for us, obviously the toxicities are things that we have learned to deal with, and we still see a small percentage of individuals who have the very worrisome toxicities, like the myocarditis, the myositis, the myasthenia gravis type symptomatology. We see those, they‘re relatively rare, but even there we usually manage to get patients through those. So I‘m a little less afraid of the toxicity, but it clearly requires a team. [Those] within the department know how to take care of it. All of our subspecialists really have developed subject matter expertise. So that gives me some confidence that we can get our patients through it.

Brian I. Rini, MD:I think when the initial ipilimumab/nivolumab data was presented, I think it was a 35% high dose steroid. It was like, whoa, that’s a lot. Now, I don’t know, we’re not that afraid of high dose steroids, but we’re afraid of the sequelae of irAEs [immune-related adverse events] and needing to use infliximab and needing to use all these other things. If you put somebody on high-dose steroids and they get better, great. I don’t think that’s a problem, in general. But when they don’t get better, require the things are obviously fatal outcomes, that’s…I’m just trying to get a sense of how much that toxicity is.

Elizabeth Plimack, MD, MS: That risk exists with all the doublets because there’s IO. So it’s more with ipilimumab-nivolumab.

Brian I. Rini, MD:But it’s way more with ipilimumab.

Stephanie A. Berg, DO: You can see it faster.

Elizabeth Plimack, MD, MS: But we’re always vigilant for all that.

Eric Jonasch, MD: I think if you look at COSMIC-313 [NCT03937219]and you look at the discontinuation rates and the toxicity rates and the steroid use for the ipilimumab-nivolumab arm in that study, it is somewhat lower than it was with CheckMate 214 [NCT02231749]. I think this is all part of our learning how to use these agents over time [that’s] really has de-risked that somewhat.

Brian I. Rini, MD:I think that’s fair. We’re going to get to triplets a little bit later.

Transcript edited for clarity.