ASCO24: The Era of the ADCs in NSCLC

Dr. Vamsi Velcheti: Hello, I am Dr. Vamsi Velcheti, your guest host for the ASCO Daily News Podcast today. I'm a professor of medicine and director of thoracic medical oncology at Perlmutter Cancer Center at NYU Langone Health. Today, I'm delighted to welcome Dr. Nathan Pennell, the co-director of the Cleveland Clinic Lung Cancer Program and vice chair of clinical research at the Taussig Cancer Center. Dr. Pennell is also the editor-in-chief of the ASCO Educational Book. Dr. Pennell is sharing his valuable insights today on key abstracts in lung cancer that will be presented at the 2024 ASCO Annual Meeting.

You'll find our full disclosures in the transcript of the episode. 

Nate, it's great to have you here on the podcast. Thank you for being here.

Dr. Nathan Pennell: Thanks, Vamsi, for inviting me. I'm always excited for the ASCO Annual Meeting, and we have a tremendous amount of exciting lung cancer abstracts. I know we're not going to discuss all of them on this podcast, but even exciting Plenary presentations coming up. 

Dr. Vamsi Velcheti: So, one of the abstracts that caught my attention was Abstract 103, the LUMINOSITY trial, which will be presenting the primary analysis at the meeting. So, there's a lot of buzz and excitement around ADCs. Can you comment on this abstract, Nate, and what are your thoughts on key takeaways from this abstract? 

Dr. Nathan Pennell: Absolutely, I agree. This is really an exciting new potential target for lung cancer. So historically, when we think about MET and lung cancer, we think about the MET exon 14 skipping mutations which are present in 3% or 4% of adenocarcinoma patients. And we have approved tyrosine kinase inhibitors, small molecule inhibitors that can be very effective for those. What we're talking about here is actually an antibody drug conjugate or ADC telisotuzumab vedotin, which is targeting the MET protein over expression in non-squamous EGFR wild type advanced non-small cell lung cancer. The LUMINOSITY was a single arm, phase 2 study of teliso, and first of all, I think we have to define the patient population. So, these were MET over expressing non-small cell lung cancer by immunohistochemical staining. So, it included both what they considered MET high expression and MET intermediate expression, both of which had to be 3+ IHC positive on 25% to 50% of cells in the intermediate and 50% or higher in the high expressing group. They were treated with the ADC and had pretty promising results, a response rate of 35% in the MET high group and 23% in the intermediate group.

Duration of response at nine months and 7.2 months in those two groups, and the PFS was five and a half and six months. So I would say in a previously treated population, this was relatively promising and potentially defines a completely new and unique subgroup of biomarker defined patients.

So, Vamsi, I'm curious, though, if this ends up moving forward to further development, what your thoughts are on adding yet another biomarker in non-small cell lung cancer?

Dr. Vamsi Velcheti: Yeah, I think it's certainly exciting. I think for this population, we really don't have a lot of options beyond the second line, and even in the second line, docetaxels are low bar. So,I think having more options for our patients is certainly outcome development. And I think MET IHC is relatively easy to deploy in a clinical setting. I think we already test for MET PD-L1 IHC routinely, and now recently, as you know, HER2 IHC given approval for ADCs, HER2 ADCs there in that space. So, I think from a technical standpoint, I don't see a big barrier in terms of adding an additional IHC marker. And usually, the IHC testing is pretty quick. And I think if you have a therapeutic approval based on IHC positivity, I think certainly from an operational standpoint, it shouldn't be a very complicated issue.

Dr. Nathan Pennell: Yeah, I agree. This is cheap. It's something that can be done everywhere in the world. And as you said, in addition to diagnostic IHC, we're already looking at PD-L1, and probably moving towards doing that for HER2. This is really wonderful that we're moving into kind of the era of the ADCs, which is opening up a whole new therapeutic group of options for patients.

Dr. Vamsi Velcheti: So, the other abstract that caught my attention was like, the Abstract 8005. This is the molecular residual disease MRD analysis from the ADAURA trial. The ADAURA trial, as you all know, is the trial that led to the FDA approval of adjuvant use of osimertinib in patients with EGFR mutant stage 1B through 3A non-small cell lung cancer. And in this trial, osimertinib demonstrated significant improvements in DFS and OS. And in this particular study, Abstract 8005, the authors looked at the role of MRD in predicting DFS in the study. And after 682 patients who were randomized, 36% of the patients had samples to look at MRD post- surgery. And in the trial the MRD status predicted DFS or event free survival at 36 months with a hazard ratio of 0.23. And the MRD status had a median lead time of 4.7 months across both the arms, both osimertinib and the placebo arm. So, suggesting that MRD could potentially identify high risk subgroups of patients post-surgery to tailor personalized approaches potentially in this population.

So, Nate, in your practice, of course, we don't have a clinically validated approach yet to kind of use MRD in this setting, but if we have an option to use an MRD based assay, do you think that would potentially be an opportunity to perhaps escalate or de-escalate adjuvant strategies with TKIs in the adjuvant setting? Do you see value in using MRI assays post- surgery?

Dr. Nathan Pennell: Yeah, I think this is a really important study because this is such an important topic around adjuvant targeted treatment. So, of course, ADAURA really changed how we treated people with EGFR mutant lung cancer who underwent surgical resection, because we know that the three years of osimertinib significantly improved disease-free survival and overall survival. But there's still a lot of questions being asked about, is that affordable?

Obviously, we're putting a lot of resources into three years of treatment, and not everyone necessarily needs it. There may well be people who are cured with surgery alone and adjuvant chemotherapy. And then what about duration? Is three years enough? Do we need even longer treatment, or do we need shorter treatment? And up to date, we haven't really been able to tell people at risk of recurrence other than the pure odds-based risk based on their stage.

And the assay that was used in the ADAURA study was a personalized tumor informed assay based on the resected tumor. It's unclear to me whether this was just a subgroup of people that had this done or whether they tried to do it in all 600 patients and only, it looks like they were successful in about 32% of people. Maybe about a third were able to successfully have a tumor informed assay. So, the first question is, "Can you use this to help guide who needs treatment or not?" And I think what they showed was only about 4% of people in osimertinib arm in 12% had MRD positive at baseline after surgery. So probably, upfront testing is not really going to be all that helpful at determining who's at high risk and needs to be treated.

Interestingly, of those who were positive, though, most of them, or 80% of them, did go MRD negative on osimertinib. And what I found really interesting is that of those who did have a recurrence, 65% of them did have the MRD test turn positive. And as you mentioned, that was about five months prior to being picked up radiographically, and so you can pick them up sooner. And it also looks like about two thirds of recurrences can be identified with the blood test. So that potentially could identify people who are recurring earlier that might be eligible for a more intensive treatment. The other thing that was really interesting is of those who recurred in the osimertinib arm, 68% of them happened after stopping the osimertinib, suggesting that for the majority of patients, even those not necessarily cured, they seem to have disease control while on the osimertinib, suggesting that maybe a longer duration of treatment for those patients could be helpful. The problem is it still isn't necessarily helpful at identifying who those people are who need the longer duration of treatment.

So, definitely an important study. I think it could be useful in practice if this was available clinically, especially at monitoring those after completion of treatment. I think as the sensitivity of these MRD assays gets better, these will become more and more important.

Dr. Vamsi Velcheti: I think it's a little bit of a challenge in terms of standardizing these assays, and they're like multiple assays, which are currently commercially available. And I think the field is getting really complicated in terms of how you incorporate different assays and different therapeutics in the adjuvant space, especially if you're kind of looking at de-escalating immunotherapeutic strategies at the adjuvant setting, I think, makes it even more challenging. I think exciting times. We definitely need more thoughtful and better studies to really define the role of MRD in the adjuvant space. So, I guess more to come in this space.

Dr. Nathan Pennell: Vamsi, I wanted to ask you about another really interesting Abstract 8011. This is a subgroup of the AEGEAN perioperative study for early-stage resected non-small cell lung cancer. This abstract is specifically looking at baseline N2 lymph node involvement in stage 2A-3B with N2 positive patients in an exploratory subgroup analysis. What are your key takeaways from the study?

Dr. Vamsi Velcheti: I felt this was a very interesting abstract for a couple of reasons. As you know, this is the AEGEAN trial, the phase 3 trial that was reported earlier last year. This is a perioperative study of durvalumab plus new adjuvant chemotherapy versus new adjuvant chemotherapy alone and adjuvant durvalumab plus placebo. The study obviously met its primary endpoint, as we all saw, like the event-free survival. And here in this abstract, the authors present an exploratory subgroup analysis of patients who had N2 lymph node involvement prior to study enrollment. So, in this study, they were focusing on perioperative outcomes. And one of the issues that has come up multiple times, as you know, in a lot of these preoperative studies, is the impact of neoadjuvant chemo immunotherapy on surgery or surgical outcomes. And consistently, across a lot of these trials, including the CheckMate 816, about 20% of patients don't end up making it to surgery. So in that light, I think this study and the findings are very interesting.

In this study, they looked at patients who had N2 nodal involvement and of the patients with N2 nodal involvement, the surgical operability or the number of patients who completed surgery was similar in both the groups. So, there was no significant difference between patients who received durva versus chemotherapy and also among patients who had N2 subgroup who had surgery, similar proportions of durvalumab and placebo arms had open versus minimally invasive versus pneumonectomy. So durvalumab didn't have a negative impact on the type of surgery that the patients had at the time of surgery. So overall, the findings were consistent with other trials, perioperative trials that we have seen. So, the surgical outcomes were not negatively impacted by adding immunotherapy in the neoadjuvant perioperative space. So, this is consistent with other trials that we have seen.

And also, the other issue, Nate, I'd like to get your opinion on is, across the board, in all the perioperative trials we have seen that about 20% of the patients actually don't end up making it a surgery. And of course, most of these perioperative trials, a lot of these patients are stage 3 patients. And my take on this was that there's probably a little bit of a patient selection issue. We generally tend to err on the side of operability when we have a stage 3 patient discussed in the tumor board, sometimes feel like the patient may downstage and could potentially go to surgery. But even in the real world, in stage 3 operable patients, what proportion of patients do you think don't end up going to surgery?

Dr. Nathan Pennell: That is such an important question that I don't think we have the best answer to. You're right. All of these perioperative studies have a relatively high- sort of 20% to 30% of people who enroll on the studies don't necessarily go to surgery. And I don't think that they've done as great a job as they could in all of these trials describing exactly what happens to these patients. So in the real world, obviously not everyone would be fit enough to go to surgery or might progress in the time between when they were diagnosed and the time as planned for surgery. But probably more of them would go to surgery if they weren't getting neoadjuvant treatment, because that would be their initial treatment. The question is, of course, is that the right choice? If someone gets 12 weeks or nine weeks of neoadjuvant treatment and then a restaging scan shows that they've had progression with metastatic disease, are those really the people that would have been optimally treated with surgery upfront, or would they just have had recurrence on their first postoperative scan? So, it's really an important question to answer.

I think the bigger one is, is the treatment preventing them through toxicity from going to treatment? And I think the studies have generally felt that few patients are missing out on the option of surgery because of toxicity being caused by the IO. And in the AEGEAN study, for example, in this subgroup, a slightly numerically higher percentage of patients in the durvalumab arm actually underwent surgery compared to those who got neoadjuvant chemo. So, it doesn't seem like we're necessarily harming people with the neoadjuvant treatment. But I know that this is a concern for patients and doctors who are undergoing this approach.

Dr. Vamsi Velcheti: Definitely, I think having multiple data sets from perioperative trials, looking at the relative impact of IO on the safety and the nature of the surgery is going to be important, and this is a very important study for that reason.

Dr. Nathan Pennell: Can I ask you another thing that I thought really interesting about this particular one is they looked at the difference between those with single station N2 and multi station N2. And I know this is one of those, should we be operating on people who have multi station N2 disease? And the AEGEAN study did include people who had multiple N2 stations where perhaps in the pre-IO era, these would have been treated with definitive chemoradiation and not surgery at all. But the disease-free survival hazard ratio was essentially the same for multi station N2 as it was in the overall population. So, has that changed the way we're approaching these patients in these multidisciplinary discussions?

Dr. Vamsi Velcheti: Absolutely, Nate. I think surgical operability is in the eye of the beholder. I think it depends on which surgeon sees the patient or how the discussion goes in the tumor boards, as you know. Certainly, I think with this optionality of having a chemo IO option and potential for downstaging, kind of pushes, at least in our practice, more of these patients who are multistation, who would have otherwise gone down the chemoradiation route are now actually going through neo adjuvant chemo IO and with the hope that they would make it to surgery. So, I think it's an interesting change in paradigm in managing our locally advanced patients. So, I think it's certainly interesting, but I guess to your point, there clearly are some patients who probably should just have chemoradiation upfront, and we may be kind of like delaying that definitive chemoradiation approach for at least a subset of patients. So, at the end of the day, I think it's a lot of clinical decision-making and I think there's going to be a little bit of art to managing these patients and it's going to be really hard to define that population for a clinical trial. 

Dr. Nathan Pennell: Yeah, clearly, multidisciplinary discussion, still very important for earliest age non-small cell lung cancer patients.

If we move back to metastatic lung cancer, let's talk about Abstract 8510 looking at one of our newer, exciting biomarkers, which are the KRAS^G12Cmutant non-small cell lung cancer.

So this is a study of a second generation KRAS^G12Cinhibitor, olomorasib, which was combined with pembrolizumab, the anti PD-1 antibody, in patients with advanced KRAS^G12C mutant non-small cell lung cancer. This is something that has been tried before with first generation G12C inhibitors, with some concerns about how safe it was to do that. So, Vamsi, what did you learn from this abstract?

Dr. Vamsi Velcheti: Definitely, I think one of the concerns that we've had in other trials is like the cumulative toxicity of adding checkpoint inhibition to G12C inhibitors, especially the sotorasib CodeBreaK trial, where we see increased rates of grade 3, 4 transaminitis. So, it is encouraging to see that some of the newer agents have less of those issues when it comes to combining the checkpoint inhibition. So especially with KRAS^G12C, as you know, these are patients who are smokers, and often these are patients who have high PDL-1 could potentially also benefit from immunotherapy. In order for these KRAS^G12C inhibitors, in order to move these targeted therapy options for these patients to the front line, I do think we need to have substantial comfort in combining the checkpoint inhibitors, which is a standard treatment approach for patients in the frontline setting. I think this is exciting, and I think they're also like, as you know, there are other KRAS^G12C inhibitors also looking to combine with checkpoint inhibition in the frontline settings. So, we'll have to kind of wait and see how the other agents will perform in the setting.

Dr. Nathan Pennell: Yeah, I completely agree. I think this is such an important area to explore specifically because unlike our other targeted oncogenes like EGFR and ALK, we have multiple options for these patients, both immunotherapy and targeted treatments. And if we could think about sequencing them or even combining them and if it could be done safely, I think that would be well worth investigating. There still was significant toxicity in this trial; 30% of people had diarrhea, even at the reduced dose, and there was transaminitis at sort of about 20% or so, although probably at a manageable level. But the response rate was really quite promising. And these are all previously IO and mostly G12C TKI pre-treated patients still had a response rate of 63%. And in those who were naive to IO and TKIs, it was 78% response rate. So, if it could be done safely, I think it's definitely worth pursuing this in further trials.

Dr. Vamsi Velcheti: And also, there's some data, preclinical data, like looking at G12C inhibition. And also we have known with MET inhibition for a long time that it could potentially augment immune responses and could be having some synergistic effect with IO. So, we'll have to wait and see, I think. But safety is really the top in mind when it comes to combining these agents with checkpoint inhibitors. So, it's really encouraging to see that some of the newer agents may be more combinable IO.

Now moving on to the next abstract, and moving on to, again, the early-stage setting. So, Abstract 8052 from our colleagues in Princess Margaret reported outcomes in early-stage non- small cell lung cancer in patients with rare targetable mutation. This is actually becoming increasingly more relevant because we are seeing at least, like with the ALINA data, with the ALK and EGFR, now with ADAURA, we know that these patients don't benefit with adjuvant immunotherapy, especially some of these rare oncogene living mutations, other than like G12C. So I always struggle with this. When you have early-stage patients, with, let's say, a ROS or a RET, where we just don't have data, and we know that those are poor actors because biologically these are aggressive tumors. So, there's a really odd clinical question to ask in terms of, what is the role of adjuvant immunotherapy? Of course, this trial and this abstract are not really addressing that. But what is your take on this abstract? If you could just summarize the abstract for us.

Dr. Nathan Pennell: Sure. Well, I think this is incredibly important, and this is an area near and dear to my own heart. And that is, of course, the whole landscape of how we manage early-stage patients has changed with both ADAURA, because we now have effective treatment in the adjuvant setting for EGFR mutant patients, and now more recently with the ALINA trial for adjuvant alectinib for ALK positive patients now being FDA-approved. So, what that means is we actually have to be testing people at diagnosis even before they would be getting adjuvant treatment, and potentially before even surgery to look for these targets. We need the PD-L1 status, we need EGFR and ALK. And if you're going to be looking at these biomarkers, I think there is a reasonable argument to be made that you should be doing broad testing for all of the targetable oncogenes in these patients. There are some studies suggesting that there's value to this and identifying them for treatment at the time of recurrence. But we also know that these patients are at high risk of recurrence and probably need to be investigated, at least in trials for the adjuvant setting.

So, this particular study looked at 201 resected, mostly adenocarcinoma patients, and then they basically sequenced them for all of the targeted oncogenes. And they were quite common, perhaps even more common than you might expect in an advanced population. So, 43% of them had KRAS^G12C mutations, 13% had EGFR Exon 20 mutation, ERBB2 or HER2 mutations found in 11%, MET mutations in 10%, ALK in 7%, ROS1 in 6%, BRAF in 5%, and RET in 2%. So quite common to find these targetable oncogenes in this particular population, perhaps a somewhat biased population at Princess Margaret Hospital, but very common. And then they looked at the outcomes of these patients without targeted adjuvant treatment. And what they found was there was a very high rate of recurrence. So, relapse-free survival was pretty high in these patients across different stages, and generally their prognosis was worse than the more common KRAS^G12C patients. Most of these, in particular the HER2 mutant patients, seem to have a significantly worse relapse free survival.

Interestingly enough, though, that did not carry over to overall survival. Overall survival was better in those who had targetable oncogenes. And my guess is that that probably had to do with the availability of targeted treatments at the time of recurrence that may have impacted overall survival. But I do think that this particularly highlights the need, the unmet need for effective adjuvant treatment in these patients. And most of them, with the exception of KRAS and perhaps BRAF, perhaps MET unlikely to benefit from adjuvant immunotherapy, as you mentioned. And so, I think we really need to be investing in trials of adjuvant targeted treatments in these populations. 

Dr. Vamsi Velcheti: Yeah, this is an area that we really don't have a lot of data. But Nate, a question for you. So tomorrow you have a patient with RET fusion, stage 2, N1 disease. What would you do? Would you offer them an adjuvant RET inhibitor?

Dr. Nathan Pennell: I think I would search really hard for a trial to give them access. But if you really want to know what I think, and I'm usually willing to tell people what I think, I think the proof of concept is there. I think we know that in the setting of highly effective and very tolerable adjuvant targeted treatment in the EGFR space with osimertinib, in the ALK space with alectinib, if anything, drugs like selpercatinib and pralsetinib in RET fusion positive lung cancer in the advanced setting are just as well tolerated and easily as effective and long lasting. And so, I think if you did a trial and they are doing trials looking at these drugs in the adjuvant space, almost certainly you're going to see the same really dramatic disease-free survival benefit from these treatments, which, at least in the EGFR space, seems to have translated into an improvement in overall survival. And so if I had a stage II or a resected stage 3, especially a RET fusion positive patient today, I would definitely talk to them about off-label use of a RET inhibitor if I could not find a trial. Now, I understand that there are going to be reimbursement issues and whatnot associated with that, but I think the extrapolation is worth discussing.