ARASENS, TRITON3, and Other Key Advances at GU23

Guest host Dr. Neeraj Agarwal and Dr. Jeanny Aragon-Ching discuss several crucial studies that will be presented at the 2023 ASCO Genitourinary Cancers Symposium, including ARASENS, TRITON3, and others in prostate cancer, as well as novel therapies in mRCC and urothelial carcinoma. TRANSCRIPT Dr. Neeraj Agarwal: Hello, and welcome to the ASCO Daily News Podcast. I'm Dr. Neeraj Agarwal, your guest host of the ASCO Daily News Podcast today. I'm the director of the Genitourinary Oncology Program, a professor of medicine at the University of Utah Huntsman Cancer Institute, and editor-in-chief of the ASCO Daily News. I'm delighted to welcome Dr. Jeanny Aragon-Ching, a medical oncologist and the clinical program director of the Genitourinary Cancers Program at the Inova Schar Cancer Institute in Virginia.   Today we will be discussing key abstracts in genitourinary oncology that will be featured at the 2023 ASCO Genitourinary Cancers Symposium.   Our full disclosures are available in the show notes, and disclosures for all guests on the podcast can be found on our transcripts at asco.org/podcasts. Jeanny, it is great to have you on the podcast today.   Dr. Jeanny Aragon-Ching: Thank you so much, Dr. Agarwal, for having me.  Dr. Neeraj Agarwal: So Jeanny, let's begin with Abstract 15 on the update on the ARASENS trial, which Dr. Maha Hussain will present [at the meeting]. In March ‘22, as we know, almost a year ago, the results of the ARASENS trials were published in the New England Journal of Medicine. Darolutamide, which is an AR signaling inhibitor plus androgen deprivation therapy plus docetaxel chemotherapy, significantly reduced the risk of death by 32.5% versus placebo plus ADT plus docetaxel. The effect of triplet therapy, including darolutamide on overall survival, was consistent across prespecified subgroups. However, survival outcomes by disease volume were not reported at the time. Can you please tell us about Abstract 15?  Dr. Jeanny Aragon-Ching: Yeah, thank you so much, Neeraj, I would be happy to. So, this new data is actually very crucial for all clinicians. The title of this abstract is “Efficacy and Safety of Darolutamide in Combination with ADT and Docetaxel by Disease Volume and Disease Risk in the Phase 3 ARASENS Study.” So, as a quick reminder, in this trial, patients were randomized 1:1 to the standard dose of darolutamide 600 milligrams twice daily or placebo with ADT and docetaxel in the metastatic hormone-sensitive prostate cancer setting.    Now remember, too, high volume disease was defined per the charted criteria, which is visceral metastases and/or four or more bone lesions, of which at least one or more has to be beyond the vertebral column or pelvis. 8And high-risk disease was actually defined per the LATITUDE criteria, which is any two or more of the following three factors: Gleason scores eight or more, bone lesions that are three or more, and the presence of measurable visceral metastases. Of all the 1,305 patients, 77% of them were actually classified as having high-volume disease, and 70% of them had high-risk disease. So, in both of these high-volume and low-volume disease patients, the triplet therapy darolutamide, ADT, and docetaxel actually improved overall survival and hazard ratio was 0.69 and 0.68, respectively. Compared to the placebo and ADT, and docetaxel arm. So overall survival improvement was also significant in patients across all risk, high-risk, or low-risk disease.   Dr. Neeraj Agarwal: So, Jeanny, this is great news. So, the main message from this abstract for our audience is that triplet therapy of darolutamide plus docetaxel plus ADT is more efficacious than the doublet of ADT plus docetaxel chemotherapy, regardless of disease volume or risk status.   One important caveat I would like to note is that triplet therapy with the darolutamide was not compared with the doublet therapy of ADT plus darolutamide or any androgen receptor signaling inhibitor such as abiraterone or apalutamide or enzalutamide, all of which have shown benefit consistently, regardless of volume status, and in the case of abiraterone, also in the context of high-risk disease setting, as we saw in the LATITUDE trial.  Dr. Jeanny Aragon-Ching: Absolutely. I agree with that, Neeraj. Those are important points to consider.   Now, moving on to a different setting in prostate cancer across the disease continuum, let's discuss Abstract 18, titled “Rucaparib for Metastatic Castrate-Resistant Prostate Cancer.” This is TRITON3 entering overall survival and efficacy of rucaparib versus docetaxel or second-generation engine pathway inhibitor therapy, which will provide us with some additional data regarding overall survival. Neeraj, based on this new abstract, can you tell us more about TRITON3, which will be presented by Dr. Alan Bryce and colleagues from the Mayo Clinic Arizona?  Dr. Neeraj Agarwal: Of course. So TRITON3 is a randomized multicenter open-label phase 3 trial where rucaparib was compared with the physician choice of docetaxel chemotherapy or abiraterone or enzalutamide in those patients who had not received chemotherapy in the metastatic castration-resistant prostate cancer setting, and they had to be progressing on a prior androgen receptor signaling inhibitor in any setting prior. So, they just had to have disease progression either in the hormone-sensitive setting or CRPC setting on one of the AR inhibitors, and they had to have a BRCA1, BRCA2, or ATM alteration.   So, in this context, these patients were randomized to rucaparib versus physician's choice of agent, which could again be docetaxel chemotherapy, abiraterone, or enzalutamide. So, OS maturity is 54% in BRCA group and 59% in the intention to treat population. In BRCA1 and BRCA2 populations, radiographic PFS, which was the primary endpoint, was 11.2 months in rucaparib group and 6.4 months in the physician choice arm. In the intention to treat population where you include all patients BRCA plus ATM patients, ATM positive patients. Radiographic PFS was 10 months almost versus 6.4 months with standard of care. And both were statistically significant as well as clinically meaningful improvement in the radiographic progression-free survival with rucaparib over physician’s choice of either docetaxel or enzalutamide, or abiraterone. I would like to note that most frequent toxicity which we see with this group of agents is most frequent grade III or more toxicity was anemia, which was present in approximately 24% patients treated with rucaparib.  Dr. Jeanny Aragon-Ching: Yeah. This is a really exciting update, Neeraj. What do you think is the key takeaway from this abstract?  Dr. Neeraj Agarwal: The key takeaway is that TRITON3 trial met its primary endpoint, and rucaparib significantly improves radiographic progression-free survival in BRCA mutation-positive patients or BRCA ATM-positive patients. Overall survival is still immature, and these results further establish rucaparib as one of the standard of care options in those patients who have metastatic CRPC with prior treatment with the AR signaling inhibitor and who harbor one of the BRCA mutations or BRCA NAT mutations.   So, Jeanny, before moving on to the renal cell carcinoma section in this podcast, there is an Abstract in prostate cancer talking about correlation between the source of funding and disparities among patients with advanced prostate cancer. So, I'm referring to that Abstract 40, titled “Source of Funding and Enrollment Disparity in Prostate Cancer Clinical Trials.” I thought this was an interesting abstract. Could you please tell us more about this abstract?  Dr. Jeanny Aragon-Ching: Absolutely, Neeraj. So, in Abstract 40, Dr. Riaz and Dr. Bryce, and colleagues actually looked at phase II and III clinical trials that involved prostate cancer patients that reported on patients with age by 65 years, and they got the data from the MEDLINE and Embase databases. Trials recruiting from the United States were considered eligible for analysis by race and ethnicity. So, in terms of race and ethnic enrollment, they found that black patients were significantly underrepresented in the industry's funded trials. Notably, no significant disparity was observed in the US government-funded trials, but Hispanics were also significantly underrepresented in industry-funded clinical trials. However, no significant disparity was seen in terms of older adults overall and by funding sources. Remarkably, Black patients' representation in industry-funded prostate cancer trials has actually decreased over the last three decades.  Dr. Neeraj Agarwal: That's concerning. So, what is your key takeaway from this trial, Jeanny?  Dr. Jeanny Aragon-Ching: The key message here is that Black and Hispanic men with prostate cancer are significantly less likely to be included in industry-sponsored clinical trials. A bigger concern is that black patients' representation actually continues to decline over time. So these results warrant a really more proactive role by regulatory bodies to ensure that a proportional representation of minorities in the industry trials, which in turn will make these results more applicable to a wider entire population of men with prostate cancer.  Dr. Neeraj Agarwal: Thanks, Jeanny. Let's move on to renal cell carcinoma. I saw some innovative research correlating the efficacy of immune checkpoint inhibitors with the time of the day these checkpoint inhibitors were administered. So, interestingly, there were two studies from two different groups of investigators showing very similar results. Please tell us about this innovative research correlating outcomes with immune checkpoint inhibitors with the time of the day these medicines or these drugs were infused into the patients.   Dr. Jeanny Aragon-Ching: Absolutely, Neeraj. I think they're very exciting and interesting. So there's actually two abstracts, so Abstract 681 and 678, which we, of course, can discuss separately. So, let's probably start first with Abstract 678. Neeraj, do you want to explain to us further about this abstract?  Dr. Neeraj Agarwal: Yes. When our center participated in that abstract, which was led by Dr. Nazli Dizman from Yale University, Dr. Dizman and colleagues examined the relationship between the time of the administration of immune checkpoint inhibitors, or ICIs, as we call them, during the time of the day, and outcomes in patients with metastatic renal cell carcinoma. So, I'd like to point out that previously Dr. Qian and colleagues reported an association between the time of day of immunotherapy infusion and survival outcomes in patients with metastatic melanoma.   In this study, Dr. Dizman and colleagues, which included our center also, patients with metastatic RCC who received nivolumab with or without ipilimumab– so these patients all received either nivolumab alone or without ipilimumab. And patients who received less than 25% of infusion after 4:30 pm. were assigned to the early-time of infusion group. So, if they have received less than 25% infusion of these immunotherapies after 04:30 pm in the evening, they belong to the early infusion group, and the rest were assigned to the late infusion group.  In the univariate analysis, numerically higher objective responses and time to treatment failure were observed in the early infusion group compared to the late infusion group. So, differences were 33% versus 25% in objective responses in early versus late infusion group. If you look at time to treatment failure, 8.3 months versus 4.4 months in early versus late infusion group. In the multivariate models, which took into account the clinical characteristics such as age, gender, line of treatment, IMDC risk category, histological subtypes, there was a trend towards improved outcomes in those who received these infusions with ICIs early in the day. So, Dr. Dizman concluded that larger randomized and controlled investigations are warranted to examine the impact of this chronal modulation, if you will, on the efficacy of immune checkpoint inhibitors in metastatic RCC sets.  Dr. Jeanny Aragon-Ching: Yeah, this is very interesting data, Neeraj. And that actually resonates closely with this other abstract by Fernandez Manias and colleagues in Abstract 681. So, in this abstract, the primary outcome was overall survival, but they did look at other secondary endpoints like time on treatment, time to the next treatment, and overall response rates. Now, because of the small number of events, the authors actually focused on just patients who received second-line immune checkpoint inhibitors. And what they did was they looked at patients who received overall more than 20% of their infusions after 04:30 pm, and they found that those who did receive actually fewer infusions had a significantly shorter time on treatment and had a worse overall survival. And similar results were seen when they looked at those who got more than 50% of their dose of checkpoint inhibitors that were administered after 04:30 pm, so interestingly enough, there was a 16% increase in the risk of death for each 10% increment of checkpoint infusion after 04:30 pm. So the key message here is that administration of checkpoint inhibitors after 04:30 pm is associated, unfortunately, with inferior outcomes. Now, these results should, of course, be further considered in the organization overall of the outpatient clinic as it can impact patient survival and outcomes.  Dr. Neeraj Agarwal: Very interesting. So similar results from two independent groups of investigators from two different continents obviously made this research area very appealing and pertinent. Ideally, I think these results should be validated prospectively, but that will take time. But investigators who have already lagged multiple phase III trials should explore validating these results in the last phase 3 trials which have already been reported and where the data on the timing of infusion is available. Once validated, I think these results may profoundly influence how we organize, as you said, Jeanny, the outpatient scheduling of these checkpoint therapy infusions compared to those who are not checkpoint inhibitors. I think this is going to have very interesting data overall, no doubt.   Before moving onto bladder cancer, I would like to discuss an important abstract related to testicular cancer patients titled “Longitudinal Evaluation of Plasma MicroRNA-371 to Detect Minimal Residual Disease and Early Relapse of Germ Cell Tumors.” Could you please tell us more about this abstract?  Dr. Jeanny Aragon-Ching: Yeah, absolutely, Neeraj. So this is a very interesting up-and-coming Abstract, it's number 407, which will be presented by Dr. Lucia Nappi and colleagues. In this study, clinical patients with stage I germ cell tumor with available plasma samples after they underwent radical orchiectomy were all included. So, they looked at sensitivity, specificity, negative, positive predictive values, an area under the curve in predicting tumor recurrence, and they evaluated the microRNA-371, I'll just call it and truncate it as miR-371, and compared the same operating characteristics of current gold standard diagnostic tests. Relapse-free survival was correlated to post-orchiectomy miR-371 status, which could be either positive or negative.   So, at a median follow-up of 41 months, 101 patients with clinical stage one germ cell tumor were included. About 35% of them experienced a disease relapse during that time of follow-up. Now, what they found was miR-371 was positive in about 63% of the relapsed patients, and the miR-371 positivity preceded clinically evident disease by a median of about three months. The specificity and positive predictive values were 100%, sensitivity was like 63%, and negative predictive value was 83.5%, so very high. No false positive results were seen. And, the authors reported that the recurrence-free survival of the patients who had positive post-orchiectomy miR-371 was significantly shorter compared to those patients who had a negative biomarker for the miR-371. So, they concluded that the miR-371 sensitivity correlated with the tumor burden, time between tumor relapse, the microRNA testing, and histology. It was notably a little bit more sensitive in non-seminomas compared to those who had seminoma.  Dr. Neeraj Agarwal: Interesting findings, indeed. So, Jeanny, what is the take-home message from this abstract?   Dr. Jeanny Aragon-Ching: Yeah, so I think the key takeaway is that microRNA-371 seems to be a good test, like a biomarker for predicting disease relapse in patients with early-stage germ cell tumor. So, additionally, its high specificity and positive predictive value in predicting relapse could really be used and utilized to guide adjuvant therapy, selections, and decisions after orchiectomy. Further validation in other studies, such as swab 1823, are currently ongoing or planned to validate its clinical utility.   So Neeraj, moving on to bladder cancer, the last abstract I'd like to mention before we wrap up the podcast is Abstract 563, titled “Utility of ctDNA in Predicting Outcome and Pathological Complete Response in Patients with Bladder Cancer as a Guide for Selective Bladder Preservation Strategies.” Neeraj, can you tell us more about this abstract?  Dr. Neeraj Agarwal: Sure. So, this study was led by Dr. Lars Dyrskjøt. He and colleagues evaluated the prognostic value of circulating tumor DNA, or ctDNA, in predicting recurrence in a cohort of 68 patients with muscle-invasive bladder cancer who received new adjuvant chemotherapy prior to cystectomy. So ctDNA was analyzed two times at baseline before new adjuvant chemotherapy and then before surgery or before cystectomy. So, patients had ctDNA assessed before neoadjuvant chemotherapy and then before cystectomy after completion of new adjuvant chemotherapy. At baseline, of the 64 patients, around 60% were ctDNA negative, and 40% were positive for ctDNA. So of those patients who were ctDNA negative, 84% achieved pathologic complete response, while in those who tested ctDNA positive, only 35% achieved their pathologic complete response after surgery.   Prior to surgery, 84% of patients were ctDNA negative, and 81% achieved pathologic complete response. While none of the ctDNA-positive patients who were positive before surgery and after neoadjuvant chemotherapy, none of them achieved pathologic complete response, which translates into a positive predictive value of 100% and a negative predictive value of 81% for this test. So based on both ctDNA time points, the probability of ctDNA negative patients to achieve a pathologic complete response was significantly higher than ctDNA positive patients.   At a median follow-up of 59 months, ctDNA-positive patients without pathologic complete response demonstrated significantly lower recurrence-free survival and overall survival compared to those who were ctDNA negative. So, I want to repeat that, at a longer follow-up, which Dr. Dyrskjøt will be presenting, ctDNA positive patients without pathologic complete response had significantly lower recurrence-free survival and overall survival compared to ctDNA negative patients. Furthermore, ctDNA status at baseline, which is before neoadjuvant chemotherapy and before cystectomy, was a better predictor of recurrence-free survival compared to pathologic complete response, which is a remarkable finding here, although it's a smaller data set.  Dr. Jeanny Aragon-Ching: Agree completely, Neeraj. So, I think the importance here, too, is upon prospective validation in larger data sets, we will find that a negative ctDNA test would help in identifying patients who can benefit more from bladder-sparing strategies.   Neeraj, any final thoughts before we wrap up the podcast today?  Dr. Neeraj Agarwal: Before I share my final thoughts, Jeanny, I would like to thank you for joining us and sharing your insights. I always find them very valuable. So, thank you so much for taking the time.   I would like to wrap up the podcast by saying we are seeing an explosion in the development of novel therapeutic approaches for our patients with genitourinary cancers. At the 2023 ASCO GU meeting, we will have multiple studies with practice-impacting data presented by investigators from around the world. I urge our listeners to come and join us in the meeting not only to celebrate these successes but also to help disseminate these cutting-edge data to practitioners and maximize the benefit for our patients across the globe.   I would like to thank our listeners for joining us today. You will find links to the abstracts which we discussed today on the transcript of this episode. Finally, if you value the insights that you hear on the ASCO Daily News Podcast, please take a moment to rate, review and subscribe wherever you get your podcasts. Thank you so much.    Disclaimer:   The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions.    Guests on this podcast express their own opinions, experiences, and conclusions. Guest statements on the podcast do not express the opinions of ASCO. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.     Find out more about today’s speakers:   Dr. Neeraj Agarwal  @neerajaimms  Dr. Jeanny Aragon-Ching  Follow ASCO on social media:    @ASCO on Twitter    ASCO on Facebook    ASCO on LinkedIn      Disclosures:   Dr. Neeraj Agarwal:    Consulting or Advisory Role: Pfizer, Bristol-Myers Squibb, AstraZeneca, Nektar, Lilly, Bayer, Pharmacyclics, Foundation Medicine, Astellas Pharma, Lilly, Exelixis, AstraZeneca, Pfizer, Merck, Novartis, Eisai, Seattle Genetics, EMD Serono, Janssen Oncology, AVEO, Calithera Biosciences, MEI Pharma, Genentech, Astellas Pharma, Foundation Medicine, and Gilead Sciences   Research Funding (Institution): Bayer, Bristol-Myers Squibb, Takeda, Pfizer, Exelixis, Amgen, AstraZeneca, Calithera Biosciences, Celldex, Eisai, Genentech, Immunomedics, Janssen, Merck, Lilly, Nektar, ORIC Pharmaceuticals, crispr therapeutics, Arvinas   Dr. Jeanny Aragon-Ching:    Honoraria: Bristol-Myers Squibb, EMD Serono, Astellas Scientific and Medical Affairs Inc   Consulting or Advisory Role: Algeta/Bayer, Dendreon, AstraZeneca, Janssen Biotech, Sanofi, EMD Serono, AstraZeneca/MedImmune, Bayer, Merck, Seattle Genetics, Pfizer, Immunomedics, Amgen, AVEO, Pfizer/Myovant, Exelixis   Speakers' Bureau: Astellas Pharma, Janssen-Ortho, Bristol-Myers Squibb , Astellas/Seattle Genetics   Travel, Accommodations, Expenses: Dendreon, Algeta/Bayer, Bristol Myers Squibb, EMD Serono, Astellas Pharma