ASCO 2025: Skin Cancer Studies Highlight Strategies for Immunotherapies

At the world’s largest oncology meeting, which concluded this week, researchers presented new findings that suggest that the timing, combination and duration of immunotherapy, as well as the order in which drugs are given, may have an even greater impact on skin cancer patient outcomes than previously understood.

The American Society of Clinical Oncology (ASCO) Annual Meeting, held May 30 through June 3 in Chicago, brought together tens of thousands of cancer professionals. This year’s event featured more than 200 sessions, including presentations from academic institutions and advocacy groups worldwide.

Among presentations related to skin cancer, the oral abstract sessions, which generally feature important, practice-changing, or newsworthy research, highlighted how melanoma is treated across stages—from early, operable disease to advanced, metastatic cases.

Key Findings and Practical Implications:

One presentation focused on the use of Merck’s Keytruda (pembrolizumab), a widely used immunotherapy, before and after surgery in people with stage II melanoma, which is when the disease has grown deeper into the skin but hasn’t metastasized. This group has historically faced a high risk of recurrence, but until now, most advances have been seen in patients with more advanced disease.

Data presented by Giorgos Constantine Karakousis, M.D., showed that giving Keytruda before and after surgery was safe and feasible, with a two-year recurrence-free survival rate of 84%. While the reduction in lymph node metastasis compared with historical rates was not statistically significant overall, a subgroup analysis found a significant benefit for patients with stage IIC disease. The findings support further research but do not yet establish a new standard for earlier-stage, high-risk melanoma.

Another presentation explored whether adding a second, newer immunotherapy agent to standard treatment could further improve outcomes. In this clinical trial, researchers tested Genentech’s Tecentriq (atezolizumab) with tiragolumab, which targets a different immune checkpoint called TIGIT, in patients with high-risk, operable stage III melanoma.

Presented by Tina J. Hieken, M.D., the phase 2 trial found that this combination led to a major pathologic response in 47% of patients with high-risk, operable stage III melanoma and a 12-month event-free survival rate of 72%. The combination had a favorable safety profile, with grade 3 or higher side effects in 15% of patients.

For patients with BRAF-mutant metastatic melanoma, a group for whom targeted therapies are also an option, a phase III trial asked whether the sequence of treatments matters. The results, presented by Michael B. Atkins, M.D., FASCO, showed that these patients had better long-term survival when treatment started with immunotherapies Opdivo (nivolumab) and Yervoy (ipilimumab), both from BMS, before switching to targeted therapy with Tafinlar (dabrafenib) and Mekinist (trametinib), both from Novartis, if needed. Five-year overall survival was 63% for the immunotherapy-first group, compared with 34% for those starting with targeted therapy.

Other notable oral abstracts addressed how long patients should stay on immunotherapy. Georgina V. Long, M.D., Ph.D., presented results showing that combining Opdivo with relatlimab after surgery did not significantly improve recurrence-free survival compared with Opdivo alone for patients with resected stage III and IV melanoma. Safety findings were consistent with known profiles, but there was no added benefit for the combination in this setting.

For patients with melanoma that has spread to the brain — a group that has traditionally seen poorer outcomes — a trial led by Zeynep Eroglu, M.D., evaluating triple therapy with Pfizer’s Braftovi (encorafenib), Pfizer’s Mektovi (binimetinib), and Opdivo found promising results. This combination resulted in a 6-month progression-free survival rate of 50%, compared with 29% for standard immunotherapy (ipilimumab and nivolumab). Both regimens had high rates of serious side effects, but the study met its primary endpoint and suggests the triplet may offer an important new option for this hard-to-treat group.

Finally, new evidence presented by Sarah Danson, Ph.D., suggests that stopping anti–PD-1 immunotherapy after one year was non-inferior to continuing treatment for at least two years in patients with metastatic melanoma, in terms of progression-free survival. However, the trial closed early and was underpowered, so continuing therapy for two years remains the standard of care for now.