Dr. John Sweetenham shares highlights from Day 5 of the 2025 ASCO Annual Meeting, including data from large trials in advanced malignant melanoma and mCSPC plus a new approach to first-line treatment for patients with multiple myeloma who are not transplant eligible.

Transcript

Hello, I’m Dr. John Sweetenham, the host of the ASCO Daily News Podcast, with my takeaways on selected abstracts from Day 5 of the 2025 ASCO Annual Meeting. My disclosures are available in the transcript of this episode.

The selected abstracts from this final day of ASCO25 include important new data from large, randomized trials in patients with advanced malignant melanoma and patients with metastatic castration-sensitive prostate cancer, as well as a new approach to the first-line treatment of patients with multiple myeloma who are not transplant eligible.

Starting with LBA9500, this study was conducted in patients with completely resected stage III or IV malignant melanoma and compared the combination of relatlimab plus nivolumab versus nivolumab alone in this population. The study, named the RELATIVITY-098 trial, was presented by Dr. Georgina Long from the University of Sydney, Australia. In her introduction to the study, Dr. Long explained that the current standard of care for adjuvant therapy of resected stage III/IV melanoma is with PD-1 monotherapy with nivolumab, but that about 50% of patients will suffer from a subsequent relapse.

In the first-line setting in patients with advanced or unresectable melanoma, the combination of nivolumab with the LAG-3 inhibitor, relatlimab, has been previously shown to improve progression-free survival in the RELATIVITY-047 trial. The current study evaluated this same combination in the adjuvant setting.

More than 1,000 patients from 24 countries were randomized to receive either nivolumab alone (546 patients) or the combination of nivolumab with relatlimab (547 patients). Both treatments were given for a maximum of 1 year or until progression of disease, unacceptable toxicity, withdrawal, or death. Various biomarker studies were also undertaken including LAG-3 and PD-1 expression on CD8-positive T cells.

The primary endpoint of the study was relapse-free survival, and Dr. Long reported that this was the same in both arms of the study. For example, at 24 months, the relapse-free survival was 64% in the monotherapy arm compared with 62% in the combination arm. The hazard ratio was 1.01 and the P value was 0.928. Metastasis-free survival was also identical in both arms. No benefit was observed for the combination in any of the prespecified subgroups. No new toxicity signals emerged compared with the RELATIVITY-047 trial.

Interestingly, the baseline surface expression of LAG-3 and co-expression of LAG-3 and PD-1 on CD8 T cells in the 098 adjuvant trial were lower than in the 047 advanced disease trial, perhaps explaining why the combination did not confer benefit over nivo alone in the adjuvant setting.

This is an important result, demonstrating that results from one clinical setting cannot always be extrapolated to another. Although the combination has gained some use in the adjuvant setting, this study clearly demonstrates that more drug in this situation is no better and that monotherapy remains the current standard of care.

Results from the AMPLITUDE trial for patients with metastatic castration-sensitive prostate cancer with alterations in homologous recombination repair (HRR) genes, in LBA5006, were presented today by Dr. Gerhardt Attard from University College London, UK.

This international, multicenter study evaluated the combination of the selective PARP inhibitor, niraparib, in combination with abiraterone acetate and prednisone. The same combination has been previously shown to improve outcomes in castration-resistant metastatic prostate cancer harboring BRCA mutations in the MAGNITUDE study. The current trial included patients with castration-sensitive disease with HRR mutations including BRCA1/2.

Six hundred and ninety-six patients were randomized between niraparib, abiraterone, and prednisone plus androgen deprivation therapy, or the same combination with placebo instead of niraparib. Permitted prior therapies included no more than 6 months of prior androgen deprivation therapy and the use of docetaxel, or prior palliative radiation therapy. The primary endpoint of the study was radiographic relapse-free survival.

Dr. Attard reported that the risk for radiographic progression-free survival in the whole population was significantly reduced by 37% with niraparib and abiraterone acetate plus prednisone compared with the placebo arm. The radiographic progression-free survival risk reduction with niraparib in the prespecified BRCA1/2 subgroup was 48% and reached statistical significance compared with the placebo arm. The secondary endpoint of time to symptomatic progression was also improved with niraparib in the HRR population and the BRCA1/2 subgroup. There was a trend for overall survival favoring the niraparib combination. However, the overall survival data were immature at this first interim analysis and did not yet reach statistical significance. No new safety concerns emerged with the toxicity data consistent with the MAGNITUDE study. Less than 5% more of the patients on the experimental arm discontinued treatment in comparison to the control arm.

The authors conclude that the AMPLITUDE study results support the use of niraparib, abiraterone, and prednisone as a new treatment option for patients with metastatic castration- sensitive prostate cancer and BRCA and homologous recombination repair gene alterations. The results certainly support this conclusion and are potentially practice-changing.

Turning to hematologic malignancies, my final selection from today’s presentations is Abstract 7504, presented by Dr. Hang Quach from St Vincent’s Hospital, Melbourne, Australia, and describes a novel combination of elranatamab, daratumumab, and lenalidomide in patients with newly diagnosed multiple myeloma who are not transplant-eligible – the so-called MagnetisMM-6 trial part 1.

Elranatamab is a novel bispecific T-cell engaging antibody directed against BCMA and CD3, which has previously been approved for certain patients with relapsed and refractory multiple myeloma. In the present study, this was combined with lenalidomide and daratumumab in newly diagnosed patients. The report today describes the dose-finding phase of this study, which was part 1, specifically addressing so-called dose level ‘G’, comprising elranatamab 76mg subcutaneously every 4 weeks plus daratumumab 1800mg subcutaneously and lenalidomide 25mg given orally.

Thirty-seven patients were entered at this dose level, of whom 32 were on treatment at the time of analysis. Early response data show an overall response rate of 97.3%. With median follow up of 7.9 months, the current CR rate is 27% with a VGPR rate of almost 68%.

The most frequent toxicities were hematologic, with neutropenia observed in 75%. Some cytokine release syndrome was observed in about 60% of patients, but none was greater than grade 2.

The authors conclude that this combination is active in untreated multiple myeloma, with manageable toxicity and evidence of responses which appear to deepen over time. The dose-finding component of this trial is continuing and will subsequently progress into a phase 3 trial based on the data from the current study. This will compare daratumumab plus lenalidomide with the same combination plus elranatamab in previously untreated patients.

That concludes our special coverage from the 2025 ASCO Annual Meeting. Thanks for listening and we hope you have enjoyed listening to our top takeaways from ASCO25. If you value the insights that you hear on the ASCO Daily News Podcast, please remember to rate, review, and subscribe wherever you get your podcasts.

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Day 5: Top Takeaways From ASCO25