Outcomes With Postrecurrence Systemic Therapy Following Adjuvant Checkpoint Inhibitor Treatment for Resected Melanoma in CheckMate 238.

PURPOSE: In phase III CheckMate 238, adjuvant nivolumab significantly improved recurrence-free survival compared with ipilimumab in patients with resected stage IIIB-C/IV melanoma without a significant difference in overall survival (OS). Here, we investigate progression-free survival (PFS) and OS after postrecurrence systemic therapy. PATIENTS AND METHODS: Patients 15 years or older with resected stage IIIB-C/IV melanoma were stratified by stage and tumor PD-L1 status and randomly assigned to receive nivolumab 3 mg/kg every 2 weeks, or ipilimumab 10 mg/kg every 3 weeks for four doses and then every 12 weeks for 1 year or until disease recurrence, unacceptable toxicity, or withdrawal of consent. Patients with recurrence in each group were assessed for PFS and OS from subsequent systemic therapy (SST) initiation per recurrence timing (≤12 months [early] v >12 months [late] from initial therapy). RESULTS: Recurrences occurred in 198 (44%) of 453 nivolumab-treated patients (122 early, 76 late) and 232 (51%) of 453 ipilimumab-treated patients (160 early, 72 late). Median PFS on next-line systemic therapy for nivolumab-treated patients recurring early versus late was 4.7 versus 12.4 months (24-month rates, 16% v 31%); median OS was 19.8 versus 42.8 months (24-month rates: 37% v 73%). In response to subsequent therapy, patients on nivolumab with late versus early recurrence were more likely to benefit from anti-PD-1 monotherapy. Nivolumab-treated patients with either an early or late recurrence benefitted from an ipilimumab-based therapy or targeted therapy, each with similar OS. CONCLUSION: Postrecurrence survival was longer for patients who recurred >12 months. Patients on nivolumab who recurred early benefitted from SST but had better survival with ipilimumab-based regimens or targeted therapy compared with anti-PD-1 monotherapy.

First-Line Nivolumab Plus Relatlimab Versus Nivolumab Plus Ipilimumab in Advanced Melanoma: An Indirect Treatment Comparison Using RELATIVITY-047 and CheckMate 067 Trial Data.

PURPOSE: Nivolumab plus relatlimab and nivolumab plus ipilimumab have been approved for advanced melanoma on the basis of the phase II/III RELATIVITY-047 and phase III CheckMate 067 trials, respectively. As no head-to-head trial comparing these regimens exists, an indirect treatment comparison was conducted using patient-level data from each trial. METHODS: Inverse probability of treatment weighting (IPTW) adjusted for baseline characteristic differences. Minimum follow-ups (RELATIVITY-047, 33 months; CheckMate 067, 36 months) were selected to best align assessments. Outcomes included progression-free survival (PFS), confirmed objective response rate (cORR), and melanoma-specific survival (MSS) per investigator; overall survival (OS); and treatment-related adverse events (TRAEs). A Cox regression model compared PFS, OS, and MSS. A logistic regression model compared cORRs. Subgroup analyses were exploratory. RESULTS: After IPTW, key baseline characteristics were balanced for nivolumab plus relatlimab (n = 339) and nivolumab plus ipilimumab (n = 297). Nivolumab plus relatlimab demonstrated similar PFS (hazard ratio [HR], 1.08 [95% CI, 0.88 to 1.33]), cORR (odds ratio, 0.91 [95% CI, 0.73 to 1.14]), OS (HR, 0.94 [95% CI, 0.75 to 1.19]), and MSS (HR, 0.86 [95% CI, 0.67 to 1.12]) to nivolumab plus ipilimumab. Subgroup comparisons showed larger numerical differences favoring nivolumab plus ipilimumab with acral melanoma, BRAF-mutant melanoma, and lactate dehydrogenase >2 × upper limit of normal, but were limited by small samples. Nivolumab plus relatlimab was associated with fewer grade 3-4 TRAEs (23% v 61%) and any-grade TRAEs leading to discontinuation (17% v 41%). CONCLUSION: Nivolumab plus relatlimab demonstrated similar efficacy to nivolumab plus ipilimumab in the overall population, including most-but not all-subgroups, and improved safety in patients with untreated advanced melanoma. Results should be interpreted with caution.

Adjuvant pembrolizumab versus placebo in resected stage III melanoma (EORTC 1325-MG/KEYNOTE-054): long-term, health-related quality-of-life results from a double-blind, randomised, controlled, phase 3 trial.

BACKGROUND: In the European Organisation for Research and Treatment of Cancer (EORTC) 1325-MG/KEYNOTE-054 study, adjuvant pembrolizumab improved recurrence-free survival and distant-metastasis-free survival in patients with resected stage III melanoma. Earlier results showed no effect of pembrolizumab on health-related quality of life (HRQOL). Little is known about HRQOL after completion of treatment with pembrolizumab, an important research area concerning patients who are likely to become long-term survivors. This study reports long-term HRQOL results. METHODS: This double-blind, randomised, controlled, phase 3 trial compared adjuvant pembrolizumab with placebo in patients aged 18 years or older with previously untreated stage IIIA, IIIB, or IIIC resected cutaneous melanoma and an Eastern Cooperative Oncology Group performance status score of 1 or 0, recruited from 123 academic centres and community hospitals in 23 countries. Patients were randomly assigned (1:1) with a minimisation technique stratified for stage and geographical region to receive 200 mg of intravenous pembrolizumab or placebo every 3 weeks for up to 18 doses. Investigators, patients, and those collecting or analysing data were masked to group assignment. The primary endpoint of the trial was recurrence-free survival (reported elsewhere). HRQOL was a prespecified exploratory endpoint, measured with the EORTC Quality of Life Questionnaire-Core 30. All patients with a baseline HRQOL evaluation available who were alive 108 weeks from randomisation were included in this analysis of long-term HRQOL. Long-term HRQOL included assessments measured every 6 months between 108 weeks and 48 months after randomisation. The threshold of clinical relevance for all HRQOL scales used was an average change of 5 points. The trial is ongoing, recruitment is completed, and HRQOL data collection is finalised. This study is registered with ClinicalTrials.gov, NCT02362594, and EudraCT, 2014-004944-37. FINDINGS: Between Aug 26, 2015, and Nov 14, 2016, 1019 patients were randomly assigned to pembrolizumab (n=514) or placebo (n=505). Completion of the HRQOL evaluation at baseline exceeded 90% (481 [94%] patients in the pembrolizumab group and 467 [92%] in the placebo group), and ranged between 60% and 90% for post-baseline timepoints. Among patients with a baseline HRQOL evaluation, 365 (39%) were female and 583 (61%) were male. The mean change from baseline to long-term HRQOL was -0·56 (95% CI -2·33 to 1·22) in the pembrolizumab group and 1·63 (-0·12 to 3·38) in the placebo group. The difference between the two groups was -2·19 (-4·65 to 0·27, p=0·081). Differences for all other scales were smaller than 5 and not statistically significant. INTERPRETATION: Adjuvant pembrolizumab did not have a significant impact on long-term HRQOL compared with placebo in patients with resected stage III melanoma. These findings, together with earlier results on efficacy and HRQOL, support the use of pembrolizumab in this setting. FUNDING: Merck Sharp & Dohme.

Baseline biomarkers of efficacy and on-treatment immune-profile changes associated with bempegaldesleukin plus nivolumab.

In PIVOT IO 001 (NCT03635983), the combination of the investigational interleukin-2 agonist bempegaldesleukin (BEMPEG) with nivolumab (NIVO) had no added clinical benefit over NIVO monotherapy in unresectable/metastatic melanoma. Pre-defined baseline and on-treatment changes in selected biomarkers were analyzed to explore the potential mechanisms underlying the clinical observations. In each treatment arm, higher baseline tumor mutational burden or immune infiltration/inflammation was associated with improved efficacy compared with lower levels. On-treatment peripheral biomarker changes showed that BEMPEG + NIVO increased all immune cell subset counts interrogated, including regulatory T cells. This was followed by attenuation of the increase in CD8 + T cells, conventional CD4 + T cells, and systemic interferon gamma levels at later treatment cycles in the combination arm. Changes in tumor biomarkers were comparable between arms. These biomarker results help provide a better understanding of the mechanism of action of BEMPEG + NIVO and may help contextualize the clinical observations from PIVOT IO 001.

Final Results for Adjuvant Dabrafenib plus Trametinib in Stage III Melanoma.

BACKGROUND: The 5-year results of this trial showed that adjuvant therapy with dabrafenib plus trametinib resulted in longer relapse-free survival and distant metastasis-free survival than placebo among patients with BRAF V600-mutated stage III melanoma. Longer-term data were needed, including data regarding overall survival. METHODS: We randomly assigned 870 patients with resected stage III melanoma with BRAF V600 mutations to receive 12 months of dabrafenib (150 mg twice daily) plus trametinib (2 mg once daily) or two matched placebos. Here, we report the final results of this trial, including results for overall survival, melanoma-specific survival, relapse-free survival, and distant metastasis-free survival. RESULTS: The median duration of follow-up was 8.33 years for dabrafenib plus trametinib and 6.87 years for placebo. Kaplan-Meier estimates for overall survival favored dabrafenib plus trametinib over placebo, although the benefit was not significant (hazard ratio for death, 0.80; 95% confidence interval [CI], 0.62 to 1.01; P = 0.06 by stratified log-rank test). A consistent survival benefit was seen across several prespecified subgroups, including the 792 patients with melanoma with a BRAF V600E mutation (hazard ratio for death, 0.75; 95% CI, 0.58 to 0.96). Relapse-free survival favored dabrafenib plus trametinib over placebo (hazard ratio for relapse or death, 0.52; 95% CI, 0.43 to 0.63), as did distant metastasis-free survival (hazard ratio for distant metastasis or death, 0.56; 95% CI, 0.44 to 0.71). No new safety signals were reported, a finding consistent with previous trial reports. CONCLUSIONS: After nearly 10 years of follow-up, adjuvant therapy with dabrafenib plus trametinib was associated with better relapse-free survival and distant metastasis-free survival than placebo among patients with resected stage III melanoma. The analysis of overall survival showed that the risk of death was 20% lower with combination therapy than with placebo, but the benefit was not significant. Among patients with melanoma with a BRAF V600E mutation, the results suggest that the risk of death was 25% lower with combination therapy. (Funded by GlaxoSmithKline and Novartis; COMBI-AD ClinicalTrials.gov number, NCT01682083; EudraCT number, 2012-001266-15.).

Neoadjuvant pembrolizumab, dabrafenib and trametinib in BRAFV600-mutant resectable melanoma: the randomized phase 2 NeoTrio trial.

Immune checkpoint inhibitors and BRAF-targeted therapy each improve survival in melanoma. Immune changes early during targeted therapy suggest the mechanisms of each drug class could work synergistically. In the non-comparative, randomized, phase 2 NeoTrio trial, we investigated whether targeted therapy could boost the proportion of patients achieving long-term recurrence-free survival with neoadjuvant immunotherapy in resectable stage III BRAFV600-mutant melanoma. Sixty patients (42% females) were randomized to pembrolizumab alone (n = 20), sequential therapy (dabrafenib plus trametinib followed by pembrolizumab; n = 20) or concurrent (triple) therapy (n = 20), followed by surgery and adjuvant therapy. The primary outcome was pathological response; secondary outcomes included radiographic response, recurrence-free survival, overall survival, surgical outcomes, peripheral blood and tumor analyses and safety. The pathological response rate was 55% (11/20; including six pathological complete responses (pCRs)) with pembrolizumab, 50% (10/20; three pCRs) with sequential therapy and 80% (16/20; ten pCRs) with concurrent therapy, which met the primary outcome in each arm. Treatment-related adverse events affected 75-100% of patients during neoadjuvant treatment, with seven early discontinuations (all in the concurrent arm). At 2 years, event-free survival was 60% with pembrolizumab, 80% with sequential therapy and 71% with concurrent therapy. Recurrences after major pathological response were more common in the targeted therapy arms, suggesting a reduction in response 'quality' when targeted therapy is added to neoadjuvant immunotherapy. Risking the curative potential of immunotherapy in melanoma cannot be justified. Pending longer follow-up, we suggest that immunotherapy and targeted therapy should not be combined in the neoadjuvant setting for melanoma. ClinicalTrials.gov registration: NCT02858921 .

Exploiting temporal aspects of cancer immunotherapy.

Many mechanisms underlying an effective immunotherapy-induced antitumour response are transient and critically time dependent. This is equally true for several immunological events in the tumour microenvironment induced by other cancer treatments. Immune checkpoint therapy (ICT) has proven to be very effective in the treatment of some cancers, but unfortunately, with many cancer types, most patients do not experience a benefit. To improve outcomes, a multitude of clinical trials are testing combinations of ICT with various other treatment modalities. Ideally, those combination treatments should take time-dependent immunological events into account. Recent studies have started to map the dynamic cellular and molecular changes that occur during treatment with ICT, in the tumour and systemically. Here, we overlay the dynamic ICT response with the therapeutic response following surgery, radiotherapy, chemotherapy and targeted therapies. We propose that by combining treatments in a time-conscious manner, we may optimally exploit the interactions between the individual therapies.

Open-label, phase II study of talimogene laherparepvec plus pembrolizumab for the treatment of advanced melanoma that progressed on prior anti-PD-1 therapy: MASTERKEY-115.

BACKGROUND: Treatment options for immunotherapy-refractory melanoma are an unmet need. The MASTERKEY-115 phase II, open-label, multicenter trial evaluated talimogene laherparepvec (T-VEC) plus pembrolizumab in advanced melanoma that progressed on prior programmed cell death protein-1 (PD-1) inhibitors. METHODS: Cohorts 1 and 2 comprised patients (unresectable/metastatic melanoma) who had primary or acquired resistance, respectively, and disease progression within 12 weeks of their last anti-PD-1 dose. Cohorts 3 and 4 comprised patients (resectable disease) who underwent complete surgery, received adjuvant anti-PD-1, and experienced recurrence. Cohort 3 were disease-free for < 6 months and cohort 4 for ≥ 6 months after starting the adjuvant anti-PD-1 therapy and before confirmed recurrence. The primary endpoint was objective response rate (ORR) per RECIST v1.1. Secondary endpoints included complete response rate (CRR), disease control rate (DCR) and progression-free survival (PFS) per RECIST v1.1 and irRC-RECIST, and safety. RESULTS: Of the 72 enrolled patients, 71 were treated. The ORR (95% CI) was 0%, 6.7% (0.2-32.0), 40.0% (16.3-67.7), and 46.7% (21.3-73.4) in cohorts 1-4, respectively; iORR was 3.8% (0.1-19.6), 6.7% (0.2-32.0), 53.3% (26.6-78.7), and 46.7% (21.3-73.4). iCRR was 0%, 0%, 13.3%, and 13.3%. Median iPFS (months) was 5.5, 8.2, not estimable [NE], and NE for cohorts 1-4, respectively; iDCR was 50.0%, 40.0%, 73.3%, and 86.7%. Treatment-related adverse events (TRAEs), grade ≥ 3 TRAEs, serious AEs, and fatal AEs occurred in 54 (76.1%), 9 (12.7%), 24 (33.8%), and 10 (14.1%) patients, respectively. CONCLUSION: T-VEC-pembrolizumab demonstrated antitumor activity and tolerability in PD-1-refractory melanoma, specifically in patients with disease recurrence on or after adjuvant anti-PD-1. TRIAL REGISTRATION: ClinicalTrials.gov identifier - NCT04068181.

Safety of pembrolizumab as adjuvant therapy in a pooled analysis of phase 3 clinical trials of melanoma, non-small cell lung cancer, and renal cell carcinoma.

BACKGROUND: The safety profile of adjuvant pembrolizumab was evaluated in a pooled analysis of 4 phase 3 clinical trials. METHODS: Patients had completely resected stage IIIA, IIIB, or IIIC melanoma per American Joint Committee on Cancer, 7th edition, criteria (AJCC-7; KEYNOTE-054); stage IIB or IIC melanoma per AJCC-8 (KEYNOTE-716); stage IB, II, or IIIA non-small cell lung cancer per AJCC-7 (PEARLS/KEYNOTE-091); or postnephrectomy/metastasectomy clear cell renal cell carcinoma at increased risk of recurrence (KEYNOTE-564). Patients received adjuvant pembrolizumab 200 mg (2 mg/kg up to 200 mg for pediatric patients) or placebo every 3 weeks for approximately 1 year. Adverse events (AEs) were summarized for patients who received ≥ 1 dose of treatment. RESULTS: Data were pooled from 4125 patients treated with pembrolizumab (n = 2060) or placebo (n = 2065). Median (range) duration of treatment was 11.1 months (0.0-18.9) with pembrolizumab and 11.2 months (0.0-18.1) with placebo. Treatment-related AEs occurred in 78.6 % (1620/2060) of patients in the pembrolizumab group (grade 3-5, 16.3 % [336/2060]) and 58.7 % (1212/2065) in the placebo group (grade 3-5, 3.5 % [72/2065]). Immune-mediated AEs (e.g. adrenal insufficiency, hypophysitis, and thyroiditis) occurred in 36.2 % (746/2060) of patients in the pembrolizumab group (grade 3-5, 8.6 % [177/2060]) and 8.4 % (174/2065) in the placebo group (grade 3-5, 1.1 % [23/2065]). Of patients with ≥ 1 immune-mediated AE or infusion reaction, systemic corticosteroids were required for 35.2 % (268/761) and 20.2 % (39/193) of patients in the pembrolizumab and placebo groups, respectively. CONCLUSIONS: Adjuvant pembrolizumab demonstrated a manageable safety profile that was comparable to prior reports in advanced disease.

Single-cell spatial multiomics reveals tumor microenvironment vulnerabilities in cancer resistance to immunotherapy.

Heterogeneous resistance to immunotherapy remains a major challenge in cancer treatment, often leading to disease progression and death. Using CITE-seq and matched 40-plex PhenoCycler tissue imaging, we performed longitudinal multimodal single-cell analysis of tumors from metastatic melanoma patients with innate resistance, acquired resistance, or response to immunotherapy. We established the multimodal integration toolkit to align transcriptomic features, cellular epitopes, and spatial information to provide deeper insights into the tumors. With longitudinal analysis, we identified an "immune-striving" tumor microenvironment marked by peri-tumor lymphoid aggregates and low infiltration of T cells in the tumor and the emergence of MITF+SPARCL1+ and CENPF+ melanoma subclones after therapy. The enrichment of B cell-associated signatures in the molecular composition of lymphoid aggregates was associated with better survival. These findings provide further insights into the establishment of microenvironmental cell interactions and molecular composition of spatial structures that could inform therapeutic intervention.

Anti-PD-1 alone or in combination with anti-CTLA-4 for advanced melanoma patients with liver metastases.

BACKGROUND: The combination of anti-PD-1 and anti-CTLA-4 has been associated with improvement in response and survival over anti-PD-1 monotherapy in unselected patients with advanced melanoma. Whether patients with liver metastases also benefit from the combination of anti-PD-1 and anti-CTLA-4 over anti-PD-1, is unclear. In this study, we sought to assess whether the combination of anti-PD-1 and anti-CTLA-4 leads to better response, progression-free survival and overall survival, compared with anti-PD-1 monotherapy for patients with liver metastases. METHODS: We have conducted an international multicentre retrospective study. Patients with advanced melanoma with liver metastases treated with 1st line anti-PD1 monotherapy or with anti-CTLA-4 were included. The endpoints of this study were: objective response rate, progression-free survival and overall survival. RESULTS: With a median follow-up from commencement of anti-PD-1 monotherapy or in combination with anti-CTLA-4 of 47 months (95% CI, 42-51), objective response rate was higher with combination therapy (47%) versus anti-PD-1 monotherapy (35%) (p = 0.0027), while progression-free survival and overall survival were not statistically different between both treatment groups. However, on multivariable analysis with multiple imputation for missing values and adjusting for predefined variables, combination of anti-PD1 and anti-CTLA-4 was associated with higher objective response (OR 2.21, 1.46 - 3.36; p < 0.001), progression-free survival (HR 0.73, 0.57 - 0.92; p = 0.009) and overall survival (HR 0.71, 0.54 - 0.94; p = 0.018) compared to anti-PD1 monotherapy. CONCLUSIONS: Findings from this study will help guide treatment selection for patients who present with liver metastases, suggesting that combination therapy should be considered for this group of patients.

The Effect of Neoadjuvant Systemic Therapy on Surgical Outcomes After Lymph Node Dissections for Stage III Melanoma; An Australian Cohort.

BACKGROUND: Neoadjuvant systemic therapy (NAST) for patients with stage III melanoma achieves high major pathologic response rates and high recurrence-free survival rates. This study aimed to determine how NAST with targeted therapies (TTs) and immune checkpoint inhibitors (ICIs) influences surgical outcomes after lymph node dissection in terms of complications, morbidity, and textbook outcomes. METHODS: Patients who underwent a lymph node dissection after either NAST in a clinical trial or upfront surgery for stage III melanoma between 2014 and 2022 were identified from an institutional research database. RESULTS: The study included 89 NAST-treated patients and 79 upfront surgery-treated patients. The rate of postoperative complications did not differ between the NAST- and upfront surgery-treated patients (55% vs. 51%; p = 0.643), and steroid treatment for drug toxicity did not influence the complication rate (odds ratio [OR], 1.1; 95% confidence interval [CI], 0.4-3; p = 0.826). No significant differences in postoperative morbidity were observed in terms of seroma (23% vs. 11%; p = 0.570) or lymphedema (36% vs. 51%; p = 0.550). The rate of achieving a textbook outcome was comparable for the two groups (61% vs. 57%; p = 0.641). CONCLUSIONS: The surgical outcomes after lymph node dissections were comparable between the patients who received NAST and those who had upfront surgery, indicating that surgery can be safely performed after NAST with TT or ICI for stage III melanoma.

POLARIS: A phase 2 trial of encorafenib plus binimetinib evaluating high-dose and standard-dose regimens in patients with BRAF V600-mutant melanoma with brain metastasis.

Background: POLARIS (phase 2 [ph2]; NCT03911869) evaluated encorafenib (BRAF inhibitor) in combination with binimetinib (MEK1/2 inhibitor) in BRAF/MEK inhibitor-naïve patients with BRAF V600-mutant melanoma with asymptomatic brain metastases. Methods: The safety lead-in (SLI) assessed tolerability for high-dose encorafenib 300 mg twice daily (BID) plus binimetinib 45 mg BID. If the high dose was tolerable in ph2, patients would be randomized to receive high or standard dose (encorafenib 450 mg once daily [QD] plus binimetinib 45 mg BID). Otherwise, standard dose was evaluated as the recommended ph2 dose (RP2D). Patients who tolerated standard dosing during Cycle 1 could be dose escalated to encorafenib 600 mg QD plus binimetinib 45 mg BID in Cycle 2. Safety, efficacy, and pharmacokinetics were examined. Results: RP2D was standard encorafenib dosing, as >33% of evaluable SLI patients (3/9) had dose-limiting toxicities. Overall, of 13 safety-evaluable patients (10 SLI, 3 ph2), 9 had prior immunotherapy. There were 9 treatment-related adverse events in the SLI and 3 in ph2. Of the SLI efficacy-evaluable patients (n = 10), 1 achieved complete response and 5 achieved partial responses (PR); the brain metastasis response rate (BMRR) was 60% (95% CI: 26.2, 87.8). In ph2, 2 of 3 patients achieved PR (BMRR, 67% [95% CI: 9.4, 99.2]). Repeated encorafenib 300 mg BID dosing did not increase steady-state exposure compared with historical 450 mg QD data. Conclusions: Despite small patient numbers due to early trial termination, BMRR appeared similar between the SLI and ph2, and the ph2 safety profile appeared consistent with previous reports of standard-dose encorafenib in combination with binimetinib.

Interferon-gamma signature as prognostic and predictive marker in macroscopic stage III melanoma.

BACKGROUND: A substantial proportion of patients with macroscopic stage III melanoma do not benefit sufficiently from adjuvant anti-PD-1 therapy, as they either recur despite therapy or would never have recurred. To better inform adjuvant treatment selection, we have performed translational analyses to identify prognostic and predictive biomarkers. PATIENTS AND METHODS: Two cohorts of patients with macroscopic stage III melanoma from an ongoing biobank study were included. Clinical data were compared between an observation cohort (cohort 1) and an adjuvant intention cohort (cohort 2). RNA sequencing for translational analyses was performed and treatment subgroups (cohort 1A and cohort 2A) were compared for possible biomarkers, using a cut-off based on the treatment-naïve patients. In addition, two validation cohorts (Melanoma Institute Australia (MIA) and University Medical Centre Utrecht (UMCU)) were obtained. RESULTS: After a median follow-up of 26 months of the 98 patients in our discovery set, median recurrence-free survival (RFS) was significantly longer for the adjuvant intention cohort (cohort 2, n=49) versus the observation cohort (cohort 1, n=49). Median overall survival was not reached for either cohort, nor significantly different. In observation cohort 1A (n=24), RFS was significantly longer for patients with high interferon-gamma (IFNγ) score (p=0.002); for adjuvant patients of cohort 2A (n=24), a similar trend was observed (p=0.086). Patients with high B cell score had a longer RFS in cohort 1A, but no difference was seen in cohort 2A. The B cell score based on RNA correlated with CD20+ cells in tumor area but was not independent from the IFNγ score. In the MIA validation cohort (n=44), longer RFS was observed for patients with high IFNγ score compared with low IFNγ score (p=0.046), no difference in RFS was observed according to the B cell score. In both the observation (n=11) and the adjuvant (n=11) UMCU validation cohorts, no difference in RFS was seen for IFNγ and B cell. CONCLUSIONS: IFNγ has shown to be a prognostic marker in both patients who were and were not treated with adjuvant therapy. B cell score was prognostic but did not improve accuracy over IFNγ. Our study confirmed RFS benefit of adjuvant anti-PD-1 for patients with macroscopic stage III melanoma.

Stroma-infiltrating T cell spatiotypes define immunotherapy outcomes in adolescent and young adult patients with melanoma.

The biological underpinnings of therapeutic resistance to immune checkpoint inhibitors (ICI) in adolescent and young adult (AYA) melanoma patients are incompletely understood. Here, we characterize the immunogenomic profile and spatial architecture of the tumor microenvironment (TME) in AYA (aged ≤ 30 years) and older adult (aged 31-84 years) patients with melanoma, to determine the AYA-specific features associated with ICI treatment outcomes. We identify two ICI-resistant spatiotypes in AYA patients with melanoma showing stroma-infiltrating lymphocytes (SILs) that are distinct from the adult TME. The SILhigh subtype was enriched in regulatory T cells in the peritumoral space and showed upregulated expression of immune checkpoint molecules, while the SILlow subtype showed a lack of immune activation. We establish a young immunosuppressive melanoma score that can predict ICI responsiveness in AYA patients and propose personalized therapeutic strategies for the ICI-resistant subgroups. These findings highlight the distinct immunogenomic profile of AYA patients, and individualized TME features in ICI-resistant AYA melanoma that require patient-specific treatment strategies.

Society for Immunotherapy of Cancer (SITC) recommendations on intratumoral immunotherapy clinical trials (IICT): from premalignant to metastatic disease.

BACKGROUND: Intratumorally delivered immunotherapies have the potential to favorably alter the local tumor microenvironment and may stimulate systemic host immunity, offering an alternative or adjunct to other local and systemic treatments. Despite their potential, these therapies have had limited success in late-phase trials for advanced cancer resulting in few formal approvals. The Society for Immunotherapy of Cancer (SITC) convened a panel of experts to determine how to design clinical trials with the greatest chance of demonstrating the benefits of intratumoral immunotherapy for patients with cancers across all stages of pathogenesis. METHODS: An Intratumoral Immunotherapy Clinical Trials Expert Panel composed of international key stakeholders from academia and industry was assembled. A multiple choice/free response survey was distributed to the panel, and the results of this survey were discussed during a half-day consensus meeting. Key discussion points are summarized in the following manuscript. RESULTS: The panel determined unique clinical trial designs tailored to different stages of cancer development-from premalignant to unresectable/metastatic-that can maximize the chance of capturing the effect of intratumoral immunotherapies. Design elements discussed included study type, patient stratification and exclusion criteria, indications of randomization, study arm determination, endpoints, biological sample collection, and response assessment with biomarkers and imaging. Populations to prioritize for the study of intratumoral immunotherapy, including stage, type of cancer and line of treatment, were also discussed along with common barriers to the development of these local treatments. CONCLUSIONS: The SITC Intratumoral Immunotherapy Clinical Trials Expert Panel has identified key considerations for the design and implementation of studies that have the greatest potential to capture the effect of intratumorally delivered immunotherapies. With more effective and standardized trial designs, the potential of intratumoral immunotherapy can be realized and lead to regulatory approvals that will extend the benefit of these local treatments to the patients who need them the most.

Pembrolizumab versus placebo as adjuvant therapy in resected stage IIB or IIC melanoma: Outcomes in histopathologic subgroups from the randomized, double-blind, phase 3 KEYNOTE-716 trial.

BACKGROUND: Adjuvant pembrolizumab significantly improved recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) versus placebo in the phase 3 KEYNOTE-716 study of resected stage IIB or IIC melanoma. At the prespecified third interim analysis (data cut-off, January 4, 2022), the HR for RFS in the overall population was 0.64 (95% CI, 0.50 to 0.84) and the HR for DMFS was 0.64 (95% CI, 0.47 to 0.88). We present a post hoc analysis of efficacy by subtypes defined by histopathologic characteristics. METHODS: Patients aged ≥12 years with newly diagnosed, resected stage IIB or IIC melanoma were randomly assigned (1:1) to pembrolizumab 200 mg every 3 weeks (2 mg/kg up to 200 mg for pediatric patients) or placebo. The primary end point was RFS per investigator review; DMFS per investigator review was secondary. Subgroups of interest were melanoma subtype (nodular vs non-nodular), tumor thickness (≤4 mm vs >4 mm), presence of ulceration (yes vs no), mitotic rate (<5 per mm2 (median) vs ≥5 per mm2), and presence of tumor-infiltrating lymphocytes (TILs; absent vs present). RESULTS: Between September 23, 2018, and November 4, 2020, 976 patients were assigned to pembrolizumab (n=487) or placebo (n=489). Median follow-up was 27.4 months (range, 14.0-39.4). The HR (95% CI) for RFS was 0.54 (0.37 to 0.79) for nodular and 0.77 (0.53 to 1.11) for non-nodular melanoma; 0.57 (0.37 to 0.89) for thickness ≤4 mm and 0.69 (0.50 to 0.96) for >4 mm; 0.66 (0.50 to 0.89) for ulceration and 0.57 (0.32 to 1.03) for no ulceration; 0.57 (0.35 to 0.92) for mitotic rate <5 per mm2 and 0.57 (0.40 to 0.80) for ≥5 per mm2; and 0.89 (0.52 to 1.54) for TILs absent and 0.51 (0.34 to 0.76) for TILs present. DMFS results were similar. In a Cox multivariate analysis, treatment arm, tumor thickness, and mitotic rate were significant independent factors for RFS, and treatment arm and mitotic rate were significant independent factors for DMFS. CONCLUSIONS: In this post hoc analysis, the benefit of pembrolizumab was largely consistent with the overall study population regardless of histopathologic characteristics. These results support the use of adjuvant pembrolizumab in patients with resected stage IIB or IIC melanoma. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT03553836.