A prediction model for response to immune checkpoint inhibition in advanced melanoma

Predicting who will benefit from treatment with immune checkpoint inhibition (ICI) in patients with advanced melanoma is challenging. We developed a multivariable prediction model for response to ICI, using routinely available clinical data including primary melanoma characteristics. We used a population-based cohort of 3525 patients with advanced cutaneous melanoma treated with anti-PD-1-based therapy. Our prediction model for predicting response within 6 months after ICI initiation was internally validated with bootstrap resampling. Performance evaluation included calibration, discrimination and internal-external cross-validation. Included patients received anti-PD-1 monotherapy (n = 2366) or ipilimumab plus nivolumab (n = 1159) in any treatment line. The model included serum lactate dehydrogenase, World Health Organization performance score, type and line of ICI, disease stage and time to first distant recurrence-all at start of ICI-, and location and type of primary melanoma, the presence of satellites and/or in-transit metastases at primary diagnosis and sex. The over-optimism adjusted area under the receiver operating characteristic was 0.66 (95% CI: 0.64-0.66). The range of predicted response probabilities was 7%-81%. Based on these probabilities, patients were categorized into quartiles. Compared to the lowest response quartile, patients in the highest quartile had a significantly longer median progression-free survival (20.0 vs 2.8 months; P < .001) and median overall survival (62.0 vs 8.0 months; P < .001). Our prediction model, based on routinely available clinical variables and primary melanoma characteristics, predicts response to ICI in patients with advanced melanoma and discriminates well between treated patients with a very good and very poor prognosis.

Discovery of tumor-reactive T cell receptors by massively parallel library synthesis and screening

T cell receptor (TCR) gene therapy is a potent form of cellular immunotherapy in which patient T cells are genetically engineered to express TCRs with defined tumor reactivity. However, the isolation of therapeutic TCRs is complicated by both the general scarcity of tumor-specific T cells among patient T cell repertoires and the patient-specific nature of T cell epitopes expressed on tumors. Here we describe a high-throughput, personalized TCR discovery pipeline that enables the assembly of complex synthetic TCR libraries in a one-pot reaction, followed by pooled expression in reporter T cells and functional genetic screening against patient-derived tumor or antigen-presenting cells. We applied the method to screen thousands of tumor-infiltrating lymphocyte (TIL)-derived TCRs from multiple patients and identified dozens of CD4+ and CD8+ T-cell-derived TCRs with potent tumor reactivity, including TCRs that recognized patient-specific neoantigens.

CD70-Targeted Allogeneic CAR T-Cell Therapy for Advanced Clear Cell Renal Cell Carcinoma

Therapeutic approaches for clear cell renal cell carcinoma (ccRCC) remain limited; however, chimeric antigen receptor (CAR) T-cell therapies may offer novel treatment options. CTX130, an allogeneic CD70-targeting CAR T-cell product, was developed for the treatment of advanced or refractory ccRCC. We report that CTX130 showed favorable preclinical proliferation and cytotoxicity profiles and completely regressed RCC xenograft tumors. We also report results from 16 patients with relapsed/refractory ccRCC who received CTX130 in a phase I, multicenter, first-in-human clinical trial. No patients encountered dose-limiting toxicity, and disease control was achieved in 81.3% of patients. One patient remains in a durable complete response at 3 years. Finally, we report on a next-generation CAR T construct, CTX131, in which synergistic potency edits to CTX130 confer improved expansion and efficacy in preclinical studies. These data represent a proof of concept for the treatment of ccRCC and other CD70+ malignancies with CD70-targeted allogeneic CAR T cells.

SIGNIFICANCE

Although the role of CAR T cells is well established in hematologic malignancies, the clinical experience in solid tumors has been disappointing. This clinical trial demonstrates the first complete response in a patient with RCC, reinforcing the potential benefit of CAR T cells in the treatment of solid tumors.

Intradermal naked DNA vaccination by DNA tattooing for mounting tumor-specific immunity in stage IV melanoma patients: a phase I clinical trial

INTRODUCTION

Naked DNA vaccination could be a powerful and safe strategy to mount antigen-specific cellular immunity. We designed a phase I clinical trial to investigate the toxicity of naked DNA vaccines encoding CD8+ T-cell epitope from tumor-associated antigen MART-1 in patients with advanced melanoma.

METHODS

This dose escalating phase Ia clinical trial investigates the toxicity and immunological response upon naked DNA vaccines encoding a CD8+ T-cell epitope from the tumor-associated antigen MART-1, genetically linked to the gene encoding domain 1 of subunit-tetanus toxin fragment C in patients with advanced melanoma (inoperable stage IIIC-IV, AJCC 7th edition). The vaccine was administrated via intradermal application using a permanent make-up or tattoo device. Safety was monitored according to CTCAE v.3.0 and skin biopsies and blood samples were obtained for immunologic monitoring.

RESULTS

Nine pretreated, HLA-A*0201-positive patients with advanced melanoma expressing MART-1 and MHC class I, with a good performance status, and adequate organ function, were included. With a median follow-up of 5.9 months, DNA vaccination was safe, without treatment-related deaths. Common treatment-emergent adverse events of any grade were dermatologic reactions at the vaccination site (100%) and pain (56%). One patient experienced grade 4 toxicity, most likely related to tumor progression. One patient (11%) achieved stable disease, lasting 353 days. Immune analysis showed no increase in vaccine-induced T cell response in peripheral blood of five patients, but did show a MART-1 specific CD8+ T cell response at the tattoo administration site. The maximum dose administered was 2 mg due to lack of clinical activity.

CONCLUSION

We showed that the developed DNA vaccine, applied using a novel intradermal application strategy, can be administered safely. Further research with improved vaccine formats is required to show possible clinical benefit of DNA vaccination.

Tumor-Infiltrating Lymphocyte and Other Cell Therapies for Metastatic Melanoma

ABSTRACT

Major progress in prolonging survival of patients with advanced melanoma has been made in the past decade because of the development and approval of immune checkpoint inhibitor and targeted therapies. However, for nonresponding or relapsing patients, their prognosis is still dismal. Based on clinical trial data, treatment with adoptive cell therapies holds great promise. In patients with metastatic melanoma progressing on or nonresponsive to single-agent anti-programmed cell death 1, infusion of tumor-infiltrating lymphocytes can produce responses in up to half of patients, with durable complete responses in up to 20%. Genetic modification of peripheral blood T cells with T-cell receptors derived from tumor-specific T cells, or with chimeric antigen receptors, has the potential to further improve treatment outcomes in this refractory population. In this review, we will discuss the historical development, current status, and future perspectives of adoptive T-cell therapies in melanoma.

Tumour-infiltrating lymphocyte therapy for patients with advanced-stage melanoma

Immunotherapy with immune-checkpoint inhibitors (ICIs) and targeted therapy with BRAF and MEK inhibitors have revolutionized the treatment of melanoma over the past decade. Despite these breakthroughs, the 5-year survival rate of patients with advanced-stage melanoma is at most 50%, emphasizing the need for additional therapeutic strategies. Adoptive cell therapy with tumour-infiltrating lymphocytes (TILs) is a therapeutic modality that has, in the past few years, demonstrated long-term clinical benefit in phase II/III trials involving patients with advanced-stage melanoma, including those with disease progression on ICIs and/or BRAF/MEK inhibitors. In this Review, we summarize the current status of TIL therapies for patients with advanced-stage melanoma, including potential upcoming marketing authorization, the characteristics of TIL therapy products, as well as future strategies that are expected to increase the efficacy of this promising cellular immunotherapy.

Adjuvant dendritic cell therapy in stage IIIB/C melanoma: the MIND-DC randomized phase III trial

Autologous natural dendritic cells (nDCs) treatment can induce tumor-specific immune responses and clinical responses in cancer patients. In this phase III clinical trial (NCT02993315), 148 patients with resected stage IIIB/C melanoma were randomized to adjuvant treatment with nDCs (n = 99) or placebo (n = 49). Active treatment consisted of intranodally injected autologous CD1c+ conventional and plasmacytoid DCs loaded with tumor antigens. The primary endpoint was the 2-year recurrence-free survival (RFS) rate, whereas the secondary endpoints included median RFS, 2-year and median overall survival, adverse event profile, and immunological response The 2-year RFS rate was 36.8% in the nDC treatment group and 46.9% in the control group (p = 0.31). Median RFS was 12.7 months vs 19.9 months, respectively (hazard ratio 1.25; 90% CI: 0.88-1.79; p = 0.29). Median overall survival was not reached in both treatment groups (hazard ratio 1.32; 90% CI: 0.73-2.38; p = 0.44). Grade 3-4 study-related adverse events occurred in 5% and 6% of patients. Functional antigen-specific T cell responses could be detected in 67.1% of patients tested in the nDC treatment group vs 3.8% of patients tested in the control group (p < 0.001). In conclusion, while adjuvant nDC treatment in stage IIIB/C melanoma patients generated specific immune responses and was well tolerated, no benefit in RFS was observed.

The Predictive Value of FDG PET/CT for Determining Progression-Free Survival in Advanced Stage III-IV BRAF -Mutated Melanoma Patients Treated With Targeted Therapy-What Can Be Learned From Progression?

PURPOSE

The aims of this study were to investigate whether (early) PERCIST response monitoring with 18 F-FDG PET/CT is predictive for progression-free survival (PFS) in unresectable stage III or IV melanoma patients treated with BRAF/MEK inhibitor (MEKi) and to define dissemination patterns at progression with a lesion-based evaluation in direct comparison to baseline to improve our understanding of 18 F-FDG PET/CT during BRAF/MEKi.

PATIENTS AND METHODS

This prospective multicenter single-arm study included 70 patients with unresectable stage III/IV BRAF -mutated melanoma who underwent contrast-enhanced CT and 18 F-FDG PET/CT at baseline and 2 and 7 weeks during treatment with vemurafenib plus cobimetinib and at progression if possible. Tumor response assessment was done with RECIST1.1 and PERCIST. Follow-up PET/CT scans were visually compared with baseline to assess dissemination patterns.

RESULTS

Using RECIST1.1, PFS was not significantly different between the response groups ( P = 0.26). At 2 weeks, PERCIST median PFS was 15.7 months for patients with complete metabolic response (CMR) versus 8.3 months for non-CMR ( P = 0.035). The hazards ratio (HR) for progression/death in non-CMR versus CMR was 1.99 (95% confidence interval [CI], 1.03-3.84; P = 0.040) and 1.77 (95% CI, 0.91-3.43; P = 0.0935) when adjusting for lactate dehydrogenase (LDH). At 7 weeks, median PFS for PERCIST CMR was 16.7 months versus 8.5 months for non-CMR ( P = 0.0003). The HR for progression/death in the non-CMR group was significantly increased (HR, 2.94; 95% CI, 1.60-5.40; P = 0.0005), even when adjusting for LDH (HR, 2.65; 95% CI, 1.43-4.91; P = 0.0020). At week 7, 18 F-FDG PET/CT was false-positive in all 4 (6%) patients with new FDG-avid lesions but CMR of known metastases. When 18 F-FDG PET/CT was performed at progressive disease, 18/22 (82%) patients had progression of known metastases with or without new 18 F-FDG-avid lesions.

CONCLUSIONS

This study shows that PERCIST response assessment at week 7 is predictive for PFS, regardless of LDH. At 2 weeks, patients with CMR have longer PFS than patients with non-CMR, but different PET parameters should be investigated to further evaluate the added value of early 18 F-FDG PET/CT. Disease progression on PET/CT is predominated by progression of known metastases, and new 18 F-FDG-avid lesions during BRAF/MEKi are not automatically a sign of recurrent disease.

Clinical presentation of cardiac symptoms following treatment with tumor-infiltrating lymphocytes: diagnostic challenges and lessons learned

BACKGROUND

Treatment with tumor-infiltrating lymphocytes (TILs) is rapidly evolving for patients with solid tumors. Following metastasectomy, TILs (autologous, intratumoral CD4+ and CD8+ T cells with the potential to recognize tumor-associated antigens) are isolated and non-specifically expanded ex vivo in the presence of interleukin-2 (IL-2). Subsequently, the TILs are adoptively transferred to the patients after a preconditioning non-myeloablative, lymphodepleting chemotherapy regimen, followed by administration of high-dose (HD) IL-2. Here, we provide an overview of known cardiac risks associated with TIL treatment and report on seven patients presenting with cardiac symptoms, all with different clinical course and diagnostic findings during treatment with lymphodepleting chemotherapy, TIL, and HD IL-2, and propose a set of clinical recommendations for diagnosis and management of these symptoms.

PATIENTS AND METHODS

This single-center, retrospective study included selected patients who experienced TIL treatment-related cardiac symptoms at the Netherlands Cancer Institute. In addition, 12 patients were included who received TIL in the clinical trial setting without experiencing cardiac symptoms, from whom complete cardiac biomarker follow-up during treatment was available [creatine kinase (CK), CK-myocardial band, troponin T and N-terminal pro-B-type natriuretic peptide].

RESULTS

Within our TIL patient population, seven illustrative cases were chosen from the patients who developed symptoms suspected of severe cardiotoxicity: myocarditis, myocardial infarction, peri-myocarditis, atrial fibrillation, acute dyspnea, and two cases of heart failure. An overview of their clinical course, diagnostics carried out, and management of the symptoms is provided.

CONCLUSIONS

In the absence of evidence-based guidelines for the treatment of TIL therapy-associated cardiotoxicity, we provided an overview of literature, case descriptions, and recommendations for diagnosis and management to help physicians in daily practice, as the number of patients qualifying for TIL treatment is rapidly increasing.

Neoadjuvant atezolizumab plus chemotherapy in gastric and gastroesophageal junction adenocarcinoma: the phase 2 PANDA trial

Gastric and gastroesophageal junction (G/GEJ) cancers carry a poor prognosis, and despite recent advancements, most patients die of their disease. Although immune checkpoint blockade became part of the standard-of-care for patients with metastatic G/GEJ cancers, its efficacy and impact on the tumor microenvironment (TME) in early disease remain largely unknown. We hypothesized higher efficacy of neoadjuvant immunotherapy plus chemotherapy in patients with nonmetastatic G/GEJ cancer. In the phase 2 PANDA trial, patients with previously untreated resectable G/GEJ tumors (n = 21) received neoadjuvant treatment with one cycle of atezolizumab monotherapy followed by four cycles of atezolizumab plus docetaxel, oxaliplatin and capecitabine. Treatment was well tolerated. There were grade 3 immune-related adverse events in two of 20 patients (10%) but no grade 4 or 5 immune-related adverse events, and all patients underwent resection without treatment-related delays, meeting the primary endpoint of safety and feasibility. Tissue was obtained at multiple time points, allowing analysis of the effects of single-agent anti-programmed cell death ligand 1 (PD-L1) and the subsequent combination with chemotherapy on the TME. Twenty of 21 patients underwent surgery and were evaluable for secondary pathologic response and survival endpoints, and 19 were evaluable for exploratory translational analyses. A major pathologic response (≤10% residual viable tumor) was observed in 14 of 20 (70%, 95% confidence interval 46-88%) patients, including 9 (45%, 95% confidence interval 23-68%) pathologic complete responses. At a median follow-up of 47 months, 13 of 14 responders were alive and disease-free, and five of six nonresponders had died as a result of recurrence. Notably, baseline anti-programmed cell death protein 1 (PD-1)+CD8+ T cell infiltration was significantly higher in responders versus nonresponders, and comparison of TME alterations following anti-PD-L1 monotherapy versus the subsequent combination with chemotherapy showed an increased immune activation on single-agent PD-1/L1 axis blockade. On the basis of these data, monotherapy anti-PD-L1 before its combination with chemotherapy warrants further exploration and validation in a larger cohort of patients with nonmetastatic G/GEJ cancer. ClinicalTrials.gov registration: NCT03448835 .

Seasonal variation of anti-PD-1 outcome in melanoma-Results from a Dutch patient cohort

Despite the improved survival rates of patients with advanced stage melanoma since the introduction of ICIs, many patients do not have (long-term) benefit from these treatments. There is evidence that the exposome, an accumulation of host-extrinsic factors including environmental influences, could impact ICI response. Recently, a survival benefit was observed in patients with BRAF wild-type melanoma living in Denmark who initiated immunotherapy in summer as compared to winter. As the Netherlands lies in close geographical proximity to Denmark and has comparable seasonal differences, a Dutch validation cohort was established using data from our nationwide melanoma registry. In this study, we did not observe a similar seasonal difference in overall survival and are therefore unable to confirm the Danish findings. Validation of either the Dutch or Danish findings in (combined) patient cohorts from other countries would be necessary to determine whether this host-extrinsic factor influences the response to ICI-treatment.

Severe Immune-Related Enteritis after In Utero Exposure to Pembrolizumab

Immune checkpoint blockade has become standard treatment for many types of cancer. Such therapy is indicated most often in patients with advanced or metastatic disease but has been increasingly used as adjuvant therapy in those with early-stage disease. Adverse events include immune-related organ inflammation resembling autoimmune diseases. We describe a case of severe immune-related gastroenterocolitis in a 4-month-old infant who presented with intractable diarrhea and failure to thrive after in utero exposure to pembrolizumab. Known causes of the symptoms were ruled out, and the diagnosis of pembrolizumab-induced immune-related gastroenterocolitis was supported by the results of histopathological assays, immunophenotyping, and analysis of the level of antibodies against programmed cell death protein 1 (PD-1). The infant's condition was successfully treated with prednisolone and infliximab.

CLDN6-specific CAR-T cells plus amplifying RNA vaccine in relapsed or refractory solid tumors: the phase 1 BNT211-01 trial

The oncofetal antigen Claudin 6 (CLDN6) is highly and specifically expressed in many solid tumors, and could be a promising treatment target. We report dose escalation results from the ongoing phase 1/2 BNT211-01 trial evaluating the safety and feasibility of chimeric antigen receptor (CAR) T cells targeting the CLDN6 with or without a CAR-T cell-amplifying RNA vaccine (CARVac) at two dose levels (DLs) in relapsed/refractory CLDN6-positive solid tumors. The primary endpoints were safety and tolerability, maximum tolerated dose and recommended phase 2 dose (RP2D). Secondary endpoints included objective response rate (ORR) and disease control rate. We observed manageable toxicity, with 10 out of 22 patients (46%) experiencing cytokine release syndrome including one grade 3 event and 1 out of 22 (5%) with grade 1 immune effector cell-associated neurotoxicity syndrome. Dose-limiting toxicities occurred in two patients at the higher DL, resolving without sequelae. CAR-T cell engraftment was robust, and the addition of CARVac was well tolerated. The unconfirmed ORR in 21 evaluable patients was 33% (7 of 21), including one complete response. The disease control rate was 67% (14 of 21), with stable disease in seven patients. Patients with germ cell tumors treated at the higher DL exhibited the highest response rate (ORR 57% (4 of 7)). The maximum tolerated dose and RP2D were not established as the trial has been amended to utilize an automated manufacturing process. A repeat of the dose escalation is ongoing and will identify a RP2D for pivotal trials. ClinicalTrials.gov Identifier: NCT04503278 .

"One more chance to survive": the experiences of patients with advanced melanoma and their partners with tumor-infiltrating lymphocyte therapy-a qualitative study and recommendations for future care

PURPOSE

Patients with advanced melanoma refractory to first-line treatment have a need for effective second-line treatment options. A recent phase 3 trial showed promising results for adoptive cell therapy with tumor-infiltrating lymphocytes (TILs) as second-line therapy in patients with advanced melanoma. However, it remains unknown how patients and their partners experience TIL therapy, which is key to evaluate and improve the quality of care.

METHODS

Semi-structured interviews about the experience of TIL therapy were conducted with patients with advanced melanoma and their partners 2-4 weeks post-treatment (short term) and >6 months after treatment (long term).

RESULTS

In total, 25 interviews were conducted with advanced melanoma patients treated with TIL (n=13) and their partners (n=12), with the majority being short-term interviews (n=17). Overall, patients and partners experienced TIL therapy as intense (uncertainty of successful TIL culture, multiple treatment-related toxicities, and extensive hospitalization). Patients and partners with young children or other caregiving responsibilities encountered the most challenges during TIL therapy. All patients, however, reported a recovery of all treatment-related toxicities within 2-4 weeks (except fatigue).

CONCLUSION

Clinical data justify the role of TIL therapy in the treatment of advanced melanoma. With the distinct nature of TIL therapy compared to the current standard of care, we have provided patient-centered recommendations that will further enhance the quality of TIL therapy.

IMPLICATIONS FOR CANCER SURVIVORS

As more patients with advanced melanoma are expected to receive TIL therapy in the future, our findings could be incorporated into survivorship care plans for this novel group of advanced melanoma survivors treated with TIL.

Oncological Outcome After Lymph Node Dissection for Cutaneous Squamous Cell Carcinoma

BACKGROUND

Although cutaneous squamous cell carcinoma (cSCC) is common, lymph node metastases are relatively rare and are usually treated with lymph node dissection (LND). The aim of this study was to describe the clinical course and prognosis after LND for cSCC at all anatomical locations.

METHODS

A retrospective search at three centres was performed to identify patients with lymph node metastases of cSCC who were treated with LND. Prognostic factors were identified by uni- and multivariable analysis.

RESULTS

A total of 268 patients were identified with a median age of 74. All lymph node metastases were treated with LND, and 65% of the patients received adjuvant radiotherapy. After LND, 35% developed recurrent disease both locoregionally and distantly. Patients with more than one positive lymph node had an increased risk for recurrent disease. 165 (62%) patients died during follow-up of whom 77 (29%) due to cSCC. The 5-year OS- and DSS rate were 36% and 52%, respectively. Disease-specific survival was significantly worse in immunosuppressed patients, patients with primary tumors >2cm and patients with more than one positive lymph node.

CONCLUSIONS

This study shows that LND for patients with lymph node metastases of cSCC leads to a 5-year DSS of 52%. After LND, approximately one-third of the patients develop recurrent disease (locoregional and/or distant), which underscores the need for better systemic treatment options for locally advanced cSCC. The size of the primary tumor, more than one positive lymph node, and immunosuppression are independent predictors for risk of recurrence and disease-specific survival after LND for cSCC.

IMPemBra: a phase 2 study comparing pembrolizumab with intermittent/short-term dual MAPK pathway inhibition plus pembrolizumab in patients with melanoma harboring the BRAFV600 mutation

BACKGROUND

Continuous combination of MAPK pathway inhibition (MAPKi) and anti-programmed death-(ligand) 1 (PD-(L)1) showed high response rates, but only limited improvement in progression-free survival (PFS) at the cost of a high frequency of treatment-related adverse events (TRAE) in patients with BRAF^V600-mutated melanoma. Short-term MAPKi induces T-cell infiltration in patients and is synergistic with anti-programmed death-1 (PD-1) in a preclinical melanoma mouse model. The aim of this phase 2b trial was to identify an optimal regimen of short-term MAPKi with dabrafenib plus trametinib in combination with pembrolizumab.

METHODS

Patients with treatment-naïve BRAF^V600E/K-mutant advanced melanoma started pembrolizumab 200 mg every 3 weeks. In week 6, patients were randomized to continue pembrolizumab only (cohort 1), or to receive, in addition, intermittent dabrafenib 150 mg two times per day plus trametinib 2 mg one time per day for two cycles of 1 week (cohort 2), two cycles of 2 weeks (cohort 3), or continuously for 6 weeks (cohort 4). All cohorts continued pembrolizumab for up to 2 years. Primary endpoints were safety and treatment-adherence. Secondary endpoints were objective response rate (ORR) at week 6, 12, 18 and PFS.

RESULTS

Between June 2016 and August 2018, 33 patients with advanced melanoma have been included and 32 were randomized. Grade 3-4 TRAE were observed in 12%, 12%, 50%, and 63% of patients in cohort 1, 2, 3, and 4, respectively. All planned targeted therapy was given in 88%, 63%, and 38% of patients in cohort 2, 3, and 4. ORR at week 6, 12, and 18 were 38%, 63%, and 63% in cohort 1; 25%, 63%, and 75% in cohort 2; 25%, 50%, and 75% in cohort 3; and 0%, 63%, and 50% in cohort 4. After a median follow-up of 43.5 months, median PFS was 10.6 months for pembrolizumab monotherapy and not reached for patients treated with pembrolizumab and intermittent dabrafenib and trametinib (p=0.17). The 2-year and 3-year landmark PFS were both 25% for cohort 1, both 63% for cohort 2, 50% and 38% for cohort 3 and 75% and 60% for cohort 4.

CONCLUSIONS

The combination of pembrolizumab plus intermittent dabrafenib and trametinib seems more feasible and tolerable than continuous triple therapy. The efficacy is promising and appears to be favorable over pembrolizumab monotherapy.

TRIAL REGISTRATION NUMBER

NCT02625337.

Unleashing NK- and CD8 T cells by combining monalizumab and trastuzumab for metastatic HER2-positive breast cancer: Results of the MIMOSA trial

The large majority of patients with HER2-positive metastatic breast cancer (MBC) will eventually develop resistance to anti-HER2 therapy and die of this disease. Despite, relatively high levels of stromal tumor infiltrating lymphocytes (sTILs), PD1-blockade has only shown modest responses. Monalizumab targets the inhibitory immune checkpoint NKG2A, thereby unleashing NK- and CD8 T cells. We hypothesized that monalizumab synergizes with trastuzumab by promoting antibody-dependent cell-mediated cytotoxicity. In the phase II MIMOSA-trial, HER2-positive MBC patients were treated with trastuzumab and 750 mg monalizumab every two weeks. Following a Simon's two-stage design, 11 patients were included in stage I of the trial. Treatment was well tolerated with no dose-limiting toxicities. No objective responses were observed. Therefore, the MIMOSA-trial did not meet its primary endpoint. In summary, despite the strong preclinical rationale, the novel combination of monalizumab and trastuzumab does not induce objective responses in heavily pre-treated HER2-positive MBC patients.

Real-world Outcomes of Ipilimumab Plus Nivolumab Combination Therapy in a Nation-wide Cohort of Advanced Melanoma Patients in the Netherlands

In phase III trials, ipilimumab plus nivolumab combination therapy is highly efficacious for advanced melanoma, despite many treatment-related grades 3-4 adverse events. Here, we report real-world safety and survival outcomes of ipilimumab plus nivolumab for advanced melanoma. Patients with advanced melanoma who received first-line ipilimumab plus nivolumab between January 1, 2015 and June 30, 2021 were selected from the Dutch Melanoma Treatment Registry. We evaluated response status at 3, 6, 12, 18, and 24 months. OS and PFS were estimated with the Kaplan-Meier method. Separate analyses were performed for patients with or without brain metastases and for patients who met the inclusion criteria of the Checkmate-067 trial. In total, 709 patients received first-line ipilimumab plus nivolumab. Three hundred sixty (50.7%) patients experienced grade 3-4 adverse events, with 211 of the (58.6%) patients requiring hospital admission. The median treatment duration was 42 days (IQR = 31-139). At 24 months, disease control was achieved in 37% of patients. Median PFS since the start of treatment was 6.6 months (95% CI: 5.3-8.7), and median OS was 28.7 months (95% CI: 20.7-42.2). CheckMate-067 trial-like patients had a 4-year OS of 50% (95% CI: 43-59). Among patients with no asymptomatic or symptomatic brain metastases, the 4-year OS probabilities were 48% (95% CI: 41-55), 45% (95% CI: 35-57), and 32% (95% CI: 23-46). Ipilimumab plus nivolumab can achieve long-term survival in advanced melanoma patients in a real-world setting, including patients not represented in the CheckMate-067 trial. However, the proportion of patients with disease control in the real world is lower compared with clinical trials.

Extended follow-up from JAVELIN Renal 101: subgroup analysis of avelumab plus axitinib versus sunitinib by the International Metastatic Renal Cell Carcinoma Database Consortium risk group in patients with advanced renal cell carcinoma

BACKGROUND

We report updated data for avelumab plus axitinib versus sunitinib in patients with advanced renal cell carcinoma from the third interim analysis of the phase III JAVELIN Renal 101 trial.

PATIENTS AND METHODS

Progression-free survival (PFS), objective response rate (ORR), and duration of response per investigator assessment (RECIST version 1.1) and overall survival (OS) were evaluated in the overall population and in International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk groups; safety was also assessed.

RESULTS

Overall, median OS [95% confidence interval (CI)] was not reached [42.2 months-not estimable (NE)] with avelumab plus axitinib versus 37.8 months (31.4-NE) with sunitinib [hazard ratio (HR) 0.79, 95% CI 0.643-0.969; one-sided P = 0.0116], and median PFS (95% CI) was 13.9 months (11.1-16.6 months) versus 8.5 months (8.2-9.7 months), respectively (HR 0.67, 95% CI 0.568-0.785; one-sided P < 0.0001). In patients with IMDC favorable-, intermediate-, poor-, or intermediate plus poor-risk disease, respectively, HRs (95% CI) for OS with avelumab plus axitinib versus sunitinib were 0.66 (0.356-1.223), 0.84 (0.649-1.084), 0.60 (0.399-0.912), and 0.79 (0.636-0.983), and HRs (95% CIs) for PFS were 0.71 (0.490-1.016), 0.71 (0.578-0.866), 0.45 (0.304-0.678), and 0.66 (0.550-0.787), respectively. ORRs, complete response rates, and durations of response favored avelumab plus axitinib overall and across all risk groups. In the avelumab plus axitinib arm, 81.1% had a grade ≥3 treatment-emergent adverse event (TEAE), and incidences of TEAEs and immune-related AEs were highest <6 months after randomization.

CONCLUSIONS

Avelumab plus axitinib continues to show improved efficacy versus sunitinib and a tolerable safety profile overall and across IMDC risk groups. The OS trend favors avelumab plus axitinib versus sunitinib, but data remain immature; follow-up is ongoing.

TRIAL REGISTRATION

ClinicalTrials.govNCT02684006; https://clinicaltrials.gov/ct2/show/NCT02684006.

The emerging role for CAR T cells in solid tumor oncology

In recent years, treatment with chimeric antigen receptor (CAR) T-cells has revolutionized the outcomes of patients with relapsed or refractory hematological malignancies with long-term remissions in >30% of patients. Similarly, the introduction of immune checkpoint inhibitor therapy changed the therapeutic landscape for several solid malignancies also leading to impressive long-term remission in patients. However, so far CAR T-cell therapy in solid tumors has shown low response rates and especially a lack of long-term remissions. This review focuses on the latest clinical advances and discusses promising results seen with CAR T-cells exploring new target antigens. We then review relevant challenges limiting long-term responses with CAR T-cell therapy in solid tumors like CAR T-cell persistence and target antigen expression. In addition, there is an increasing understanding on T-cell function and dysfunction within the immunosuppressive tumor microenvironment. This comprises of inhibitory cytokines and checkpoint molecules limiting the killing capacity of CAR T-cells. Finally, we will discuss how this deeper knowledge can be used to develop CAR T-cell therapies overcoming these inhibitory factors and results in CAR T-cell products with higher efficacy and safety. These technological developments will hopefully lead to enhanced clinical activity and improved solid tumor patient outcomes in the near future.

Exposure-response analyses of BRAF- and MEK-inhibitors dabrafenib plus trametinib in melanoma patients

INTRODUCTION

Dabrafenib and trametinib are currently administered at fixed doses, at which interpatient variability in exposure is high. The aim of this study was to investigate whether drug exposure is related to efficacy and toxicity in a real-life cohort of melanoma patients treated with dabrafenib plus trametinib.

PATIENTS AND METHODS

An observational study was performed in which pharmacokinetic samples were collected as routine care. Using estimated dabrafenib Area Under the concentration-time Curve and trametinib trough concentrations (C_min), univariable and multivariable exposure-response analyses were performed.

RESULTS

In total, 140 patients were included. Dabrafenib exposure was not related to either progression-free survival (PFS) or overall survival (OS). Trametinib exposure was related to survival, with C_min ≥ 15.6 ng/mL being identified as the optimal threshold. Median OS was significantly longer in patients with trametinib C_min ≥ 15.6 ng/mL (22.8 vs. 12.6 months, P = 0.003), with a multivariable hazard ratio of 0.55 (95% CI 0.36-0.85, P = 0.007). Median PFS in patients with trametinib C_min levels ≥ 15.6 ng/mL (37%) was 10.9 months, compared with 6.0 months for those with C_min below this threshold (P = 0.06). Multivariable analysis resulted in a hazard ratio of 0.70 (95% CI 0.47-1.05, P = 0.082). Exposure to dabrafenib and trametinib was not related to clinically relevant toxicities.

CONCLUSIONS

Overall survival of metastasized melanoma patients with trametinib C_min levels ≥ 15.6 ng/mL is ten months longer compared to patients with C_min below this threshold. This would theoretically provide a rationale for therapeutic drug monitoring of trametinib. Although a high proportion of patients are underexposed, there is very little scope for dose increments due to the risk of serious toxicity.

OX40 agonism enhances PD-L1 checkpoint blockade by shifting the cytotoxic T cell differentiation spectrum

Immune checkpoint therapy (ICT) has the power to eradicate cancer, but the mechanisms that determine effective therapy-induced immune responses are not fully understood. Here, using high-dimensional single-cell profiling, we interrogate whether the landscape of T cell states in the peripheral blood predict responses to combinatorial targeting of the OX40 costimulatory and PD-1 inhibitory pathways. Single-cell RNA sequencing and mass cytometry expose systemic and dynamic activation states of therapy-responsive CD4⁺ and CD8⁺ T cells in tumor-bearing mice with expression of distinct natural killer (NK) cell receptors, granzymes, and chemokines/chemokine receptors. Moreover, similar NK cell receptor-expressing CD8⁺ T cells are also detected in the blood of immunotherapy-responsive cancer patients. Targeting the NK cell and chemokine receptors in tumor-bearing mice shows the functional importance of these receptors for therapy-induced anti-tumor immunity. These findings provide a better understanding of ICT and highlight the use and targeting of dynamic biomarkers on T cells to improve cancer immunotherapy.

Time interval from primary melanoma to first distant recurrence in relation to patient outcomes in advanced melanoma

Since the introduction of BRAF(/MEK) inhibition and immune checkpoint inhibition (ICI), the prognosis of advanced melanoma has greatly improved. Melanoma is known for its remarkably long time to first distant recurrence (TFDR), which can be decades in some patients and is partly attributed to immune-surveillance. We investigated the relationship between TFDR and patient outcomes after systemic treatment for advanced melanoma. We selected patients undergoing first-line systemic therapy for advanced melanoma from the nationwide Dutch Melanoma Treatment Registry. The association between TFDR and progression-free survival (PFS) and overall survival (OS) was assessed by Cox proportional hazard regression models. The TFDR was modeled categorically, linearly, and flexibly using restricted cubic splines. Patients received anti-PD-1-based treatment (n = 1844) or BRAF(/MEK) inhibition (n = 1618). For ICI-treated patients with a TFDR <2 years, median OS was 25.0 months, compared to 37.3 months for a TFDR >5 years (P = .014). Patients treated with BRAF(/MEK) inhibition with a longer TFDR also had a significantly longer median OS (8.6 months for TFDR <2 years compared to 11.1 months for >5 years, P = .004). The hazard of dying rapidly decreased with increasing TFDR until approximately 5 years (HR 0.87), after which the hazard of dying further decreased with increasing TFDR, but less strongly (HR 0.82 for a TFDR of 10 years and HR 0.79 for a TFDR of 15 years). Results were similar when stratifying for type of treatment. Advanced melanoma patients with longer TFDR have a prolonged PFS and OS, irrespective of being treated with first-line ICI or targeted therapy.

Radiotherapy, atezolizumab, and bevacizumab in rectal cancers with the aim of organ preservation: The TARZAN study

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Background: Rectal cancer is traditionally treated with total mesorectal excision (TME), with/without neoadjuvant radiotherapy (RT) and chemotherapy. This approach often leads to temporary or permanent colostomies and other long-term morbidity such as urinary and sexual dysfunction in over 60% of patients. Organ preservation is increasingly being pursued in patients with a clinical complete response (cCR) following neoadjuvant treatment, thereby aiming to avoid TME-surgery. Based on preclinical data suggesting immunomodulatory effects of RT, and the synergy of combined PD-L1/VEGF blockade in several tumor types, the TARZAN study (NCT04017455) combines these treatments aiming to increase chances of organ preservation in patients with mainly MMR proficient (pMMR) rectal cancer without the need for chemotherapy. Methods: Patients with clinical stage ≤T3ab N0-1 distal-mid rectal tumors without mesorectal fascia involvement underwent 5x5 Gy RT followed by 3 cycles of atezolizumab and bevacizumab. Response was evaluated by MRI and endoscopy. The primary endpoint was clinical complete and near-complete response (CR) rate at 12 weeks after RT. Secondary endpoints included safety, organ preservation, pathologic (near) CR in case of surgery, and relapse free survival. According to a Simon’s 2-stage design, ≥3 responders were needed in stage I (18 patients) to continue accrual into stage II. Here we report data from stage I. Results: Eighteen patients (14 male, median age 63), all with pMMR tumors, were treated. Six tumors were cN1 on MRI, 10/18 tumors were ≥4cm and for 10/18 patients abdominoperineal resection (APR) appeared necessary due to distal tumor location. At the time of response evaluation, (near-)CR was achieved in 10/18 (56%) patients according to the primary endpoint. With a median follow-up of 20 months, 9/18 (50%) patients remain without TME surgery. Of these 9 patients, 5 underwent local excision to achieve organ preservation and in 5 patients no additional intervention was needed (cCR). The remaining 9 patients underwent TME surgery (4 APR), and pathologic assessment revealed near-CR in two patients, and a pCR in one patient. Three patients developed distant recurrences, one in the organ-sparing group. Neoadjuvant treatment was well-tolerated with grade 3 study drug-related adverse events (AEs) in 1 (5%) patient. Grade 3 surgery-related AEs occurred in 5/9 (55%) patients, including 4 anastomotic leaks and 1 abscess. Conclusions: Neoadjuvant RT followed by atezolizumab and bevacizumab resulted in a promising rate of clinical (near-)CRs in 56% of patients without the need for chemotherapy, reaching the primary endpoint. Accrual is ongoing in stage II, in which an additional 20 patients will be treated. Clinical trial information: NCT04017455 .

Survival update of neoadjuvant ipilimumab plus nivolumab in macroscopic stage III melanoma in the OpACIN and OpACIN-neo trials

BACKGROUND

Neoadjuvant ipilimumab plus nivolumab has yielded high response rates in patients with macroscopic stage III melanoma. These response rates translated to high short-term survival rates. However, data on long-term survival and disease recurrence are lacking.

PATIENTS AND METHODS

In OpACIN, 20 patients with macroscopic stage III melanoma were randomized to ipilimumab 3 mg/kg plus nivolumab 1 mg/kg q3w four cycles of adjuvant or split two cycles of neoadjuvant and two adjuvant. In OpACIN-neo, 86 patients with macroscopic stage III melanoma were randomized to arm A (2× ipilimumab 3 mg/kg plus nivolumab 1 mg/kg q3w; n = 30), arm B (2× ipilimumab 1 mg/kg plus nivolumab 3 mg/kg q3w; n = 30), or arm C (2× ipilimumab 3 mg/kg q3w plus 2× nivolumab 3 mg/kg q2w; n = 26) followed by surgery.

RESULTS

The median recurrence-free survival (RFS) and overall survival (OS) were not reached in either trial. After a median follow-up of 69 months for OpACIN, 1/7 patients with a pathologic response to neoadjuvant therapy had disease recurrence. The estimated 5-year RFS and OS rates for the neoadjuvant arm were 70% and 90% versus 60% and 70% for the adjuvant arm. After a median follow-up of 47 months for OpACIN-neo, the estimated 3-year RFS and OS rates were 82% and 92%, respectively. The estimated 3-year RFS rate for OpACIN-neo was 95% for patients with a pathologic response versus 37% for patients without a pathologic response (P < 0.001). In multiple regression analyses, pathologic response was the strongest predictor of disease recurrence. Of the 12 patients with distant disease recurrence after neoadjuvant therapy, 5 responded to subsequent anti-PD-1 and 8 to targeted therapy, although 7 patients showed progression after the initial response.

CONCLUSIONS

Updated data confirm the high survival rates after neoadjuvant combination checkpoint inhibition in macroscopic stage III melanoma, especially for patients with a pathologic response. Pathologic response is the strongest surrogate marker for long-term outcome.

Adjuvant BRAF-MEK Inhibitors versus Anti PD-1 Therapy in Stage III Melanoma: A Propensity-Matched Outcome Analysis

Adjuvant BRAF/MEK- and anti-PD-1 inhibition have significantly improved recurrence-free survival (RFS) compared to placebo in resected stage III BRAF-mutant melanoma. However, data beyond the clinical trial setting are limited. This study describes the toxicity and survival of patients treated with adjuvant BRAF/MEK inhibitors and compares outcomes to adjuvant anti-PD-1. For this study, stage III BRAF V600 mutant cutaneous melanoma patients treated with adjuvant BRAF/MEK-inhibition or anti-PD-1 were identified from the Dutch Melanoma Treatment Registry. BRAF/MEK- and anti-PD-1-treated patients were matched based on propensity scores, and RFS at 12 and 18 months were estimated. Between 1 July 2018 and 31 December 2021, 717 patients were identified. Of these, 114 patients with complete records were treated with BRAF/MEK therapy and 532 with anti-PD-1. Comorbidities (p = 0.04) and geographical region (p < 0.01) were associated with treatment choice. In 45.6% of BRAF/MEK-treated patients, treatment was prematurely discontinued. Grade ≥ 3 toxicity occurred in 11.5% of patients and was the most common cause of early discontinuation (71.1%). At 12 and 18 months, RFS in BRAF/MEK-treated patients was 85% and 70%, compared to 68% and 68% in matched anti-PD-1-treated patients (p = 0.03). In conclusion, comorbidities and geographical region determine the choice of adjuvant treatment in patients with resected stage III BRAF-mutant melanoma. With the currently limited follow-up, BRAF/MEK-treated patients have better RFS at 12 months than matched anti-PD-1-treated patients, but this difference is no longer observed at 18 months. Therefore, longer follow-up data are necessary to estimate long-term effectiveness.

Identification of patient-specific CD4+ and CD8+ T cell neoantigens through HLA-unbiased genetic screens

Cancer neoantigens that arise from tumor mutations are drivers of tumor-specific T cell responses, but identification of T cell-recognized neoantigens in individual patients is challenging. Previous methods have restricted antigen discovery to selected HLA alleles, thereby limiting the breadth of neoantigen repertoires that can be uncovered. Here, we develop a genetic neoantigen screening system that allows sensitive identification of CD4⁺ and CD8⁺ T cell-recognized neoantigens across patients' complete HLA genotypes.

Is a History of Optimal Staging by Sentinel Lymph Node Biopsy in the Era Prior to Adjuvant Therapy Associated with Improved Outcome Once Melanoma Patients have Progressed to Advanced Disease?

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is important for staging in patients with primary cutaneous melanoma. Did having previously undergone SLNB also affect outcomes in patients once they have progressed to metastatic melanoma in the era prior to adjuvant therapy?

METHODS

Data were retrieved from the Dutch Melanoma Treatment Registry, a prospectively collected, nationwide database of patients with unresectable stage IIIC or IV (advanced) melanoma between 2012 and 2018. Melanoma-specific survival (MSS) was compared between patients with advanced cutaneous melanoma, previously treated with a wide local excision (WLE) or WLE combined with SLNB as initial treatment of their primary tumor. Cox regression analyses were used to analyze the influence of different variables on MSS.

RESULTS

In total, 2581 patients were included, of whom 1412 were treated with a WLE of the primary tumor alone and 1169 in whom this was combined with SLNB. At a median follow-up of 44 months from diagnosis of advanced melanoma, MSS was significantly longer in patients who had previously undergone SLNB {median 23 months (95% confidence interval [CI] 19-29) vs. 18 months (95% CI 15-20) for patients treated with WLE alone; p = 0.002}. However, multivariate Cox regression did not identify SLNB as an independent favorable prognostic factor for MSS after diagnosis of advanced melanoma.

CONCLUSION

Prior to the availability of adjuvant systemic therapy, once patients have unresectable stage IIIC or IV (advanced) melanoma, there was no difference in disease outcome for patients who were or were not previously staged with SLNB.

Tumor-Infiltrating Lymphocyte Therapy or Ipilimumab in Advanced Melanoma

BACKGROUND

Immune checkpoint inhibitors and targeted therapies have dramatically improved outcomes in patients with advanced melanoma, but approximately half these patients will not have a durable benefit. Phase 1-2 trials of adoptive cell therapy with tumor-infiltrating lymphocytes (TILs) have shown promising responses, but data from phase 3 trials are lacking to determine the role of TILs in treating advanced melanoma.

METHODS

In this phase 3, multicenter, open-label trial, we randomly assigned patients with unresectable stage IIIC or IV melanoma in a 1:1 ratio to receive TIL or anti-cytotoxic T-lymphocyte antigen 4 therapy (ipilimumab at 3 mg per kilogram of body weight). Infusion of at least 5×10⁹ TILs was preceded by nonmyeloablative, lymphodepleting chemotherapy (cyclophosphamide plus fludarabine) and followed by high-dose interleukin-2. The primary end point was progression-free survival.

RESULTS

A total of 168 patients (86% with disease refractory to anti-programmed death 1 treatment) were assigned to receive TILs (84 patients) or ipilimumab (84 patients). In the intention-to-treat population, median progression-free survival was 7.2 months (95% confidence interval [CI], 4.2 to 13.1) in the TIL group and 3.1 months (95% CI, 3.0 to 4.3) in the ipilimumab group (hazard ratio for progression or death, 0.50; 95% CI, 0.35 to 0.72; P<0.001); 49% (95% CI, 38 to 60) and 21% (95% CI, 13 to 32) of the patients, respectively, had an objective response. Median overall survival was 25.8 months (95% CI, 18.2 to not reached) in the TIL group and 18.9 months (95% CI, 13.8 to 32.6) in the ipilimumab group. Treatment-related adverse events of grade 3 or higher occurred in all patients who received TILs and in 57% of those who received ipilimumab; in the TIL group, these events were mainly chemotherapy-related myelosuppression.

CONCLUSIONS

In patients with advanced melanoma, progression-free survival was significantly longer among those who received TIL therapy than among those who received ipilimumab. (Funded by the Dutch Cancer Society and others; ClinicalTrials.gov number, NCT02278887.).

Association of Immune-Related Adverse Event Management With Survival in Patients With Advanced Melanoma

Importance

Management of checkpoint inhibitor-induced immune-related adverse events (irAEs) is primarily based on expert opinion. Recent studies have suggested detrimental effects of anti-tumor necrosis factor on checkpoint-inhibitor efficacy.

Objective

To determine the association of toxic effect management with progression-free survival (PFS), overall survival (OS), and melanoma-specific survival (MSS) in patients with advanced melanoma treated with first-line ipilimumab-nivolumab combination therapy.

Design, Setting, and Participants

This population-based, multicenter cohort study included patients with advanced melanoma experiencing grade 3 and higher irAEs after treatment with first-line ipilimumab and nivolumab between 2015 and 2021. Data were collected from the Dutch Melanoma Treatment Registry. Median follow-up was 23.6 months.

Main Outcomes and Measures

The PFS, OS, and MSS were analyzed according to toxic effect management regimen. Cox proportional hazard regression was used to assess factors associated with PFS and OS.

Results

Of 771 patients treated with ipilimumab and nivolumab, 350 patients (median [IQR] age, 60.0 [51.0-68.0] years; 206 [58.9%] male) were treated with immunosuppression for severe irAEs. Of these patients, 235 received steroids alone, and 115 received steroids with second-line immunosuppressants. Colitis and hepatitis were the most frequently reported types of toxic effects. Except for type of toxic effect, no statistically significant differences existed at baseline. Median PFS was statistically significantly longer for patients treated with steroids alone compared with patients treated with steroids plus second-line immunosuppressants (11.3 [95% CI, 9.6-19.6] months vs 5.4 [95% CI, 4.5-12.4] months; P = .01). Median OS was also statistically significantly longer for the group receiving steroids alone compared with those receiving steroids plus second-line immunosuppressants (46.1 months [95% CI, 39.0 months-not reached (NR)] vs 22.5 months [95% CI, 36.5 months-NR]; P = .04). Median MSS was also better in the group receiving steroids alone compared with the group receiving steroids plus second-line immunosuppressants (NR [95% CI, 46.1 months-NR] vs 28.8 months [95% CI, 20.5 months-NR]; P = .006). After adjustment for potential confounders, patients treated with steroids plus second-line immunosuppressants showed a trend toward a higher risk of progression (adjusted hazard ratio, 1.40 [95% CI, 1.00-1.97]; P = .05) and had a higher risk of death (adjusted hazard ratio, 1.54 [95% CI, 1.03-2.30]; P = .04) compared with those receiving steroids alone.

Conclusions and Relevance

In this cohort study, second-line immunosuppression for irAEs was associated with impaired PFS, OS, and MSS in patients with advanced melanoma treated with first-line ipilimumab and nivolumab. These findings stress the importance of assessing the effects of differential irAE management strategies, not only in patients with melanoma but also other tumor types.

Systemic Therapy in Advanced Nodular Melanoma versus Superficial Spreading Melanoma: A Nation-Wide Study of the Dutch Melanoma Treatment Registry

Nodular melanoma (NM) is associated with a higher locoregional and distant recurrence rate compared with superficial spreading melanoma (SSM); it is unknown whether the efficacy of systemic therapy is limited. Here, we compare the efficacy of immunotherapy and BRAF/MEK inhibitors (BRAF/MEKi) in advanced NM to SSM. Patients with advanced stage IIIc and stage IV NM and SSM treated with anti-CTLA-4 and/or anti-PD-1, or BRAF/MEKi in the first line, were included from the prospective Dutch Melanoma Treatment Registry. The primary objectives were distant metastasis-free survival (DMFS) and overall survival (OS). In total, 1086 NM and 2246 SSM patients were included. DMFS was significantly shorter for advanced NM patients at 1.9 years (CI 95% 0.7−4.2) compared with SSM patients at 3.1 years (CI 95% 1.3−6.2) (p < 0.01). Multivariate survival analysis for immunotherapy and BRAF/MEKi demonstrated a hazard ratio for immunotherapy of 1.0 (CI 95% 0.85−1.17) and BRAF/MEKi of 0.95 (CI 95% 0.81−1.11). A shorter DMFS for NM patients developing advanced disease compared with SSM patients was observed, while no difference was observed in the efficacy of systemic immunotherapy or BRAF/MEKi between NM and SSM patients. Our results suggests that the worse overall survival of NM is mainly driven by propensity of metastatic outgrowth of NM after primary diagnosis.

Signatures of recent activation identify a circulating T cell compartment containing tumor-specific antigen receptors with high avidity

T cell receptor (TCR) avidity is assumed to be a major determinant of the spatiotemporal fate and protective capacity of tumor-specific T cells. However, monitoring polyclonal T cell responses with known TCR avidities in vivo over space and time remains challenging. Here, we investigated the fate and functionality of tumor neoantigen-specific T cells with TCRs of distinct avidities in a well-established, reductionist preclinical tumor model and human patients with melanoma. To this end, we used polyclonal T cell transfers with in-depth characterized TCRs together with flow cytometric phenotyping in mice inoculated with MC38 OVA tumors. Transfer of T cells from retrogenic mice harboring TCRs with high avidity resulted in best tumor protection. Unexpectedly, we found that both high- and low-avidity T cells are similarly abundant within the tumor and adopt concordant phenotypic signs of exhaustion. Outside the tumor, high-avidity TCR T cells were not generally overrepresented but, instead, selectively enriched in T cell populations with intermediate PD-1 protein expression. Single-cell sequencing of neoantigen-specific T cells from two patients with melanoma-combined with transgenic reexpression of identified TCRs by CRISPR-Cas9-mediated orthotopic TCR replacement-revealed high-functionality TCRs to be enriched in T cells with RNA signatures of recent activation. Furthermore, of 130 surface protein candidates, PD-1 surface expression was most consistently enriched in functional TCRs. Together, our findings show that tumor-reactive TCRs with high protective capacity circulating in peripheral blood are characterized by a signature of recent activation.

Neoadjuvant nivolumab + T-VEC combination therapy for resectable early stage or metastatic (IIIB-IVM1a) melanoma with injectable disease: study protocol of the NIVEC trial

Background

Trials investigating neoadjuvant treatment with immune checkpoint inhibitors (ICI) in patients with melanoma have shown high clinical and pathologic response rates. Treatment with talimogene laherparepvec (T-VEC), a modified herpes simplex virus type-1 (HSV-1), is approved for patients with unresectable stage IIIB-IVM1a melanoma and has the potential to make tumors more susceptible for ICI. Combination ICI and intralesional T-VEC has already been investigated in patients with unresectable stage IIIB-IV disease, however, no data is available yet on the potential benefit of this combination therapy in neoadjuvant setting.

Methods

This single center, single arm, phase II study aims to show an improved major pathologic complete response (pCR) rate, either pCR or near-pCR, up to 45% in 24 patients with resectable stage IIIB-IVM1a melanoma upon neoadjuvant combination treatment with intralesional T-VEC and systemic nivolumab (anti-PD-1 antibody). Patients will receive four courses of T-VEC up to 4 mL (first dose as seroconversion dose) and three doses of nivolumab (240 mg flatdose) every 2 weeks, followed by surgical resection in week nine. The primary endpoint of this trial is pathologic response rate. Secondary endpoints are safety, the rate of delay of surgery and event-free survival. Additionally, prognostic and predictive biomarker research and health-related quality of life evaluation will be performed.

Discussion

Intralesional T-VEC has the capacity to heighten the immune response and to elicit an abscopal effect in melanoma in combination with ICI. However, the potential clinical benefit of T-VEC plus ICI in the neoadjuvant setting remains unknown. This is the first trial investigating the efficacy and safety of neoadjuvant treatment of T-VEC and nivolumab followed by surgical resection in patients with stage IIIB-IVM1a melanoma, with the potential of high pathologic response rates and acceptable toxicity.

Trial registration

This trial was registered in the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT- number: 2019–001911-22) and the Central Committee on Research Involving Human Subjects (NL71866.000.19) on 4th June 2020.

Secondary identifying number: NCT04330430.

Diagnostic performance of early increase in S100B or LDH as outcome predictor for non-responsiveness to anti-PD-1 monotherapy in advanced melanoma

As a subset of advanced melanoma patients derive long-term benefit from anti-PD-1 therapy, early identification of non-responsiveness would enable an early switch to next line therapies. This study assessed if an early increase in S100B or lactate dehydrogenase (LDH) could be predictive for non-responsiveness to anti-PD-1. We retrospectively analysed advanced melanoma patients treated with anti-PD-1 monotherapy. Serum S100B and LDH levels were measured at baseline and before every infusion. Non-response was defined as progression or death at 6 months. Marker cut-offs were defined based on > 95% specificity and feasibility in clinical practice. For validation an independent cohort was analysed. In total, 313 patients were included (166 patients in training cohort, 147 patients in validation cohort). Increase of > 50% in LDH or > 100% in S100B above upper limit of normal at week 6 compared to baseline was determined as criterion to positively test for non-responsiveness. In the validation cohort, obtained specificity of the combination test was > 95% with a positive predictive value of 82%; obtained sensitivity was lower (21%), with a negative predictive value of 55%. Early increase in S100B or LDH is a strong parameter for non-responsiveness to anti-PD-1 in advanced melanoma. Prospective confirmation is needed before clinical implementation.

Long-term survival in advanced melanoma for patients treated with nivolumab plus ipilimumab in CheckMate 067

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Background: Durable clinical benefit has been achieved with nivolumab (NIVO) + ipilimumab (IPI), including an overall survival (OS) of 49% and a melanoma-specific survival (MSS) of 56%, with median MSS not reached (NR) at 6.5-y minimum follow-up. Here we report sustained efficacy outcomes at 7.5 y. Methods: Patients (pts) with previously untreated, unresectable stage III/IV melanoma were randomly assigned 1:1:1 and stratified by PD-L1 status, BRAF mutation status, and metastasis stage to receive NIVO 1 mg/kg + IPI 3 mg/kg for 4 doses Q3W, followed by NIVO 3 mg/kg Q2W (n = 314); NIVO 3 mg/kg Q2W + placebo (n = 316); or IPI 3 mg/kg Q3W for 4 doses + placebo (n = 315) until progression or unacceptable toxicity. Co-primary endpoints were progression-free survival (PFS) and OS with NIVO + IPI or NIVO alone versus IPI. Results: With a minimum follow-up of 7.5 y, median OS remained stable at 72.1 mo (NIVO + IPI), 36.9 mo (NIVO), and 19.9 mo (IPI); median MSS was NR, 49.4 mo, and 21.9 mo, respectively (Table). While the objective response rate remained stable at 58% (NIVO + IPI), 45% (NIVO), and 19% (IPI), median duration of response had now been reached for NIVO at 90.8 mo and remains NR and 19.2 mo for NIVO + IPI and IPI, respectively. Subsequent systemic therapy was received by 36%, 49%, and 66% of NIVO + IPI-, NIVO-, and IPI-treated patients, respectively, and median time to that therapy was NR (95% CI, 45.9–NR), 24.7 mo (16.0–38.7), and 8.0 mo (6.5–8.7). Of patients alive at 7.5 y, 106/138 (77%, NIVO + IPI), 80/115 (70%, NIVO), and 27/60 (45%, IPI) were off treatment and had never received subsequent systemic therapy. No change to the safety summary was observed with additional follow-up; updated health-related quality of life data will be reported. Of the 10 new deaths since the 6.5-y follow-up (ie, 5 NIVO + IPI; 3 NIVO; 2 IPI), none were treatment-related; 4 were due to melanoma progression; 1 was due to an unknown cause; and 5 were due to other causes, but not associated with a COVID diagnosis. Conclusions: The 7.5-y follow-up continues to demonstrate the durability of responses with NIVO + IPI and an ongoing survival plateau. A substantial difference in median OS and MSS between patients treated with NIVO + IPI or NIVO was observed in descriptive analyses. Clinical trial information: NCT04540705. [Table: see text]

Neoadjuvant atezolizumab plus docetaxel/oxaliplatin/capecitabine in non-metastatic gastric and gastroesophageal junction adenocarcinoma: The PANDA trial

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Background: Immune checkpoint blockade improves clinical outcomes for patients with gastric and gastro-esophageal junction (GEJ) cancers, but its efficacy and impact on the tumor microenvironment in non-metastatic, resectable disease remains largely unknown. Peri-operative FLOT, the current standard-of-care, leads to pathologic complete responses (pCR) and major pathologic responses (MPR) in 16% and 37% of patients, respectively. An important open question is whether PDL-1 blockade monotherapy can prime the tumor microenvironment in a favorable manner, prior to combination with chemotherapy. Methods: We report results from the phase 2 PANDA trial (NCT03448835) of neoadjuvant atezolizumab (anti-PDL-1) plus docetaxel, oxaliplatin, and capecitabine (DOC) in patients with resectable gastric or GEJ adenocarcinoma. Patients received a single cycle of atezolizumab monotherapy, followed by 4 cycles of atezolizumab+DOC. Tumor tissue was collected at baseline, after atezolizumab monotherapy, the first atezolizumab+DOC, and at resection. The primary endpoints were safety and feasibility in 20 patients, and secondary endpoints included MPR (<10% viable tumor rest) and disease-free survival. Results: Twenty patients, of which 18 with mismatch repair (MMR) proficient and two with MMR-deficient tumors, were evaluable for safety and efficacy analyses. MPR was observed in 14/20 patients (70%; 95% CI 46–88%), including 9 pCR (45%; 95% CI 23-68%). Among patients with intestinal type adenocarcinoma, 12/15 (80%; 95% CI 52-96%) had an MPR, with 9/15 (60%; 95% CI 32-84%) pCR. Treatment was well tolerated, with two patients (10%) experiencing a grade 3 immune adverse event. At a median follow-up of 29 months (IQR 16-34), 15 patients (75%) were alive and disease-free. None of the patients with an MPR recurred. All patients underwent resections without treatment-related delays and no unexpected surgical complications were documented. Translational analyses, including baseline PDL-1 CPS score and whole exome sequencing (WES), plus CD8 T-cell infiltration and RNA sequencing at 4 timepoints will be presented at the meeting. Conclusions: Our data show that the addition of atezolizumab to neoadjuvant chemotherapy leads to promising pathologic responses in gastric/GEJ adenocarcinoma, which appears to be higher than in historical controls, with no recurrences in responders. These data should be validated in a large randomized controlled trial. Clinical trial information: NCT03448835.

Personalized response-directed surgery and adjuvant therapy after neoadjuvant ipilimumab and nivolumab in high-risk stage III melanoma: the PRADO trial

Neoadjuvant ipilimumab and nivolumab induces high pathologic response rates (pRRs) in clinical stage III nodal melanoma, and pathologic response is strongly associated with prolonged relapse-free survival (RFS). The PRADO extension cohort of the OpACIN-neo trial ( NCT02977052 ) addressed the feasibility and effect on clinical outcome of using pathologic response after neoadjuvant ipilimumab and nivolumab as a criterion for further treatment personalization. In total, 99 patients with clinical stage IIIb-d nodal melanoma were included and treated with 6 weeks of neoadjuvant ipilimumab 1 mg kg-1 and nivolumab 3 mg kg-1. In patients achieving major pathologic response (MPR, ≤10% viable tumor) in their index lymph node (ILN, the largest lymph node metastasis at baseline), therapeutic lymph node dissection (TLND) and adjuvant therapy were omitted. Patients with pathologic partial response (pPR; >10 to ≤50% viable tumor) underwent TLND only, whereas patients with pathologic non-response (pNR; >50% viable tumor) underwent TLND and adjuvant systemic therapy ± synchronous radiotherapy. Primary objectives were confirmation of pRR (ILN, at week 6) of the winner neoadjuvant combination scheme identified in OpACIN-neo; to investigate whether TLND can be safely omitted in patients achieving MPR; and to investigate whether RFS at 24 months can be improved for patients achieving pNR. ILN resection and ILN-response-tailored treatment were feasible. The pRR was 72%, including 61% MPR. Grade 3-4 toxicity within the first 12 weeks was observed in 22 (22%) patients. TLND was omitted in 59 of 60 patients with MPR, resulting in significantly lower surgical morbidity and better quality of life. The 24-month relapse-free survival and distant metastasis-free survival rates were 93% and 98% in patients with MPR, 64% and 64% in patients with pPR, and 71% and 76% in patients with pNR, respectively. These findings provide a strong rationale for randomized clinical trials testing response-directed treatment personalization after neoadjuvant ipilimumab and nivolumab.

Neoadjuvant nivolumab, ipilimumab, and celecoxib in MMR-proficient and MMR-deficient colon cancers: Final clinical analysis of the NICHE study

3511

Background: The combination of PD-1 and CTLA4 blockade has changed the treatment landscape for several cancer types. Although this treatment is highly effective in metastatic mismatch-repair deficient (dMMR) colorectal cancers, metastatic MMR-proficient (pMMR) tumors do not respond. The NICHE study was the first neoadjuvant immunotherapy study in colon cancer (CC) to show impressive responses in 100% of dMMR ( n= 20) and 27% of pMMR ( n= 15) CC. In contrast, pathologic response to neoadjuvant chemotherapy using standard of care folfox is approximately 5% in dMMR tumors. Here we present the final efficacy data for the original NICHE study cohorts. Methods: Patients with non-metastatic, resectable dMMR or pMMR CC were treated with a single dose of ipilimumab 1mg/kg and two doses of nivolumab 3mg/kg and underwent surgery within 6 weeks. In addition, patients with pMMR tumors were randomized to receive celecoxib. The primary endpoints were safety and feasibility, and secondary endpoints included pathologic response rate and disease-free survival in 30 patients with dMMR and 30 with pMMR tumors. Pathologic response was defined as 50% or less viable tumor rest (VTR), and major pathologic response (MPR) as <10% VTR. Results: Thirty patients with pMMR and 32 with dMMR tumors were evaluable for the efficacy analyses. In the pMMR cohort, pathologic response was observed in 9/30 (30%, 95% CI 14-46%) patients, consisting of 7 MPR (including 3 pathologic complete responses {pCR}) and 2 partial responses. Four out of 9 pMMR responders had received celecoxib. Five patients received adjuvant chemotherapy. At a median follow-up of 25 months (IQR 12-35 months), 3 patients (all non-responders) in the pMMR group had disease recurrence. In the 32 patients with dMMR tumors, pathologic response was observed in 100% of patients, with 31/32 MPR (97%, 95% CI 91-100%) and one partial response. Pathologic complete response was observed in 22/32 (69%, 95% CI 53-85%) patients. None of the patients in the dMMR cohort had disease recurrence. Surgery was delayed in one patient with a pMMR tumor due to myositis. Grade 3 immune-related adverse events were observed in 12% of patients, consistent with our previous report on the primary endpoint. There were no grade 4 immune-related AEs nor unexpected surgical complications. Conclusions: These data confirm our previously published results of the NICHE study, with responses to neoadjuvant nivolumab plus ipilimumab in 30% of pMMR and 100% of dMMR CC in the completed original cohorts. Validation of the dMMR responses in a large group of dMMR patients is ongoing and has the potential to change current practice. Clinical trial information: NCT03026140.

Adjuvant treatment of in-transit melanoma: Addressing the knowledge gap left by clinical trials

9577

Background: Few clinical trials address the efficacy of adjuvant systemic treatment in patients with ITM. This study describes the efficacy of adjuvant systemic therapy of ITM patients beyond the clinical trial setting. Methods: All stage III adjuvant-treated melanoma patients registered in the nationwide Dutch Melanoma Treatment Registry between 01-07-2018 and 31-12-2020 were included. Patients were divided into three groups: patients with ITM only, with ITM and nodal disease, and patients with nodal disease only. Differences in recurrence patterns were analysed. An exploratory analysis was performed for stage III patients who underwent surgical resection without adjuvant treatment. Recurrence-free survival (RFS) and overall survival (OS) at 12-months were assessed. Results: A total of 1037 stage III melanoma patients received adjuvant anti-PD-1 therapy, and 260 underwent surgical resection only. Of the adjuvant-treated patients, 16.9% had ITM only, 15.5% had ITM with nodal disease, and 66.8% had nodal disease only. Of the surgical resection only patients 20.4% had ITM only, 12.3% had ITM with nodal disease and 67.3% had nodal disease only. In the adjuvant-treated patients, 12-months RFS was comparable between patients with ITM only and patients with nodal disease only (71.1% vs. 72.2% respectively, p = 0.95), but significantly lower for patients with ITM and nodal disease (57.1%; ITM with nodal disease vs. ITM-only p = 0.01, and ITM with nodal disease vs. nodal disease only p < 0.01). Locoregional metastases occurred as first recurrence site in 72.7% of ITM-only patients, 42.9% of ITM and nodal disease patients and 38.9% of patients with nodal disease only, while distant recurrences occurred in 18.2% of patients with ITM only, in 36.7% of patients with ITM and nodal disease, and in 42.3% of patients with nodal disease only (p = 0.01). OS at 12-months was significantly higher for ITM-only patients compared to patients with ITM and nodal disease (97.7% vs. 90.6%, p < 0.01), and was better compared to patients with nodal disease only (97.7% vs. 94.4%, p = 0.05). OS at 12-months was comparable for patients with ITM and nodal disease and patients with nodal disease only (p = 0.19). In general, surgery-only ITM patients were older and had a worse performance score. 12-months RFS appeared worse compared to adjuvant-treated ITM patients (36.6% vs. 68.3%). In this group of surgery-only ITM patients OS at 12-months also appeared worse compared to adjuvant-treated ITM patients (89.7% vs. 95.5%). Conclusions: RFS rates in ITM-only patients are similar to non-ITM patients, while RFS in patients with ITM and nodal disease is shorter. Adjuvant-treated patients with ITM without nodal disease less often experience distant recurrences and have a superior OS compared to other adjuvant stage III patients. Our results suggest that other treatment strategies for ITM patients with nodal disease should be considered.

Management of checkpoint inhibitor toxicity and survival in patients with advanced melanoma

9546

Background: Management of checkpoint-inhibitor-induced immune-related adverse events (irAEs) is primarily based on expert opinion. Recent studies have suggested detrimental effects of immunosuppressive treatment with anti-TNF on checkpoint-inhibitor efficacy. Methods: Advanced melanoma patients experiencing grade ≥3 irAEs after treatment with first-line ipilimumab-nivolumab between 2015 and 2021 were included from the Dutch Melanoma Treatment Registry. Progression-free survival (PFS), overall survival (OS) and melanoma-specific survival (MSS) were analyzed according to toxicity management regimen. A cox proportional hazards model was used to account for the confounders age, sex, performance status, lactate dehydrogenase, site of metastases and type of irAE. Results: Out of 771 ipilimumab-nivolumab treated patients, 350 were treated with immunosuppression for severe irAEs. Of these patients, 235 received steroids only and 115 received steroids with second-line immunosuppressants consisting of anti-TNF, mycophenolic acid, tacrolimus and other immunosuppressants. Median PFS was significantly longer for patients treated with steroids (11.3 months) than for patients treated with steroids and second-line immunosuppressants (5.4 months; HR 1.43; 95%CI 1.07-1.90; p = 0.01). Median OS was also significantly longer for the steroids group (46.1 months) than for the steroids and second-line immunosuppressants group (22.5 months; HR 1.64; 95%CI 1.16-2.32; p = 0.005). Results for MSS were similar (not reached versus 28.8 months; HR 1.70; 95%CI 1.16-2.49; p = 0.006). Median PFS, OS and MSS are shown in Table 1. After adjustment for potential confounders, patients treated with steroids + second-line immunosuppressants showed a non-significant trend towards a higher risk of progression (HRadj 1.40; 95%CI 1.00-1.97; p = 0.05), a higher risk of death (HRadj 1.54; 95%CI 1.03-2.30; p = 0.04) and of melanoma-specific death (HRadj 1.62; 95%CI 1.04-2.51; p = 0.032) compared to the steroids group. Conclusions: Second-line immunosuppression for irAEs is associated with impaired PFS, OS, and MSS in advanced melanoma patients treated with first-line ipilimumab-nivolumab, irrespective of being anti-TNF or other second-line immunosuppressants. These findings stress the importance of assessing the effects of differential irAE management strategies, not only in melanoma but also in other tumor types. [Table: see text]

IMPemBra, a phase 2 study comparing pembrolizumab with intermittent/short‐term dual MAPK pathway inhibition plus pembrolizumab in patients with melanoma harboring the BRAFV600 mutation: Three-year survival data and translational analyses

9552

Background: Continuous combination of MAPK pathway inhibition (MAPKi) and anti-PD-(L)1 showed high response rates, but also high frequency of treatment-related adverse events (TRAE) in BRAFV600-mutated melanoma patients (pts). Short‐time MAPKi already induces T cell infiltration in pts and was synergistic with anti-PD‐1 in a pre-clinical model. This phase 2b trial aimed to identify the optimal duration of MAPKi with dabrafenib + trametinib (D+T) in combination with pembrolizumab (PEM). We have previously shown that no SUSARs were observed, toxicity was related to duration of D+T, and response rates increased after addition of D+T. Here we present 3-year PFS and OS data and results of translational analyses. Methods: In IMPemBra, pts with treatment-naïve BRAFV600E/K mutant advanced melanoma started with PEM 200mg Q3W. After 2 cycles, pts were randomized to continue PEM only (cohort 1) or to receive in addition intermittent dabrafenib 150 mg BID + trametinib 2mg QD for 2 x 1 week (cohort 2), 2 x 2 weeks (cohort 3) or continuous for 6 weeks (cohort 4). All cohorts continued PEM for up to 2 years. Primary endpoints were safety, treatment adherence and immune-activating capacity of the different regimens. Secondary endpoints were objective response rate (ORR) and PFS, OS was an exploratory endpoint. For survival analyses, pts that received D+T (cohort 2-4) were pooled. Results: Thirty-two pts were randomized, 56% were male, 53% had M1c disease and 88% had a LDH level < ULN. No new grade 3-4 TRAE were observed; frequencies were 12%, 12%, 50% and 62% for pts in cohort 1, 2, 3 and 4, respectively. ORRs were 75% in cohort 1 and 2, and 88% in cohort 3 and 4. The frequency of PD1+CD8+ T cells in peripheral blood decreased slightly during treatment and there were no differences between cohorts. In cohort 1 and 2, an increase in IFNγ signature in tumor biopsies was already observed after 6 weeks of PEM, in cohort 3-4 an increase in IFNγ signature was observed in week 9, after addition of D+T. The same pattern was observed for CD8+ T cell infiltration and PD-L1 expression. After a median follow-up of 43.5 months, the median PFS of pts treated with PEM monotherapy was 10.6 months versus 32.3 months for pts treated with PEM plus D+T (p = 0.19). The 3-year PFS rates were 25.0% and 50.0% respectively. Median OS was 40.5 months in the PEM pts and not reached for pts treated with PEM plus D+T (p = 0.32); 3-year OS rates were 62.5% and 70.8% respectively. Conclusions: IMPemBra demonstrated that short-term addition of intermittent D+T to PEM seems a more feasible, tolerable and an effective alternative for the continuous triple combination. In addition, it gives the opportunity to treat with second line targeted therapy after disease progression. Therefore, this regimen should be considered for further investigation in a larger cohort. Clinical trial information: NCT02625337.

Survival update of neoadjuvant ipilimumab + nivolumab in macroscopic stage III melanoma: The OpACIN and OpACIN-neo trials

9572

Background: OpACIN was the first trial testing neoadjuvant ipilimumab (IPI) + nivolumab (NIVO) versus the same combination given adjuvant. An unexpected high pathologic responses of 78% was observed in the neoadjuvant arm with a 2-year relapse-free survival (RFS) rate of 80%. The subsequent OpACIN-neo trial tested 3 different dosing schedules of neoadjuvant IPI + NIVO and identified 2 cycles IPI 1 mg/kg + NIVO 3 mg/kg q3w as most favorable schedule with a pathologic response rate of 77% and 20% grade 3-4 immune-related adverse events. Long-term data on the durability of the pathologic (path) responses upon neoadjuvant checkpoint inhibition are lacking so far. Therefore, we present here the updated RFS and overall survival (OS) data of both trials. Methods: In OpACIN 20 macroscopic stage III melanoma pts were randomized to receive either IPI 3 mg/kg + NIVO 1 mg/kg q3w 4 cycles adjuvant after lymph node dissection or split 2 cycles neoadjuvant and 2 adjuvant. In OpACIN-neo 86 macroscopic stage III melanoma pts were randomized to arm A (2x IPI 3 mg/kg + NIVO 1 mg/kg q3w, n=30), arm B (2x IPI 1 mg/kg + NIVO 3 mg/kg q3w, n=30), or arm C (2x IPI 3 mg/kg q3w followed by 2x NIVO 3 mg/kg q2w, n=26) followed by lymph node dissection in week 6. RFS and OS were estimated using Kaplan Meier method. All comparative efficacy endpoints are descriptive for OpACIN, since the trial was not powered for comparison of the arms. Results: After a median follow-up (FU) of 68.6 months for OpACIN (minimum FU of 59.8 months), median RFS and OS were not reached. Only 1/7 patients (pts) with a pathologic response on neoadjuvant therapy has relapsed. Estimated 5-year RFS and OS rates for the neoadjuvant arm were 70.0% (95%CI: 46.7-100.0) and 90.0% (95%CI: 73.2-100.0) versus 60.0% (95%CI 36.2-99.5) and 70.0% (95%CI: 46.7-100.0) for the adjuvant arm. After a median FU of 46.8 months for OpACIN-neo (minimum FU of 38.2 months), median RFS and OS were not reached. Of pts with path response on neoadjuvant therapy, 3/64 (4.7%) had an event (2 pts relapsed, 1 pt died due to toxicity), versus 14/21 (66.7%) without path response. This resulted in a 3-year RFS rate of 95.3% (95%CI: 90.3-100.0) for responding versus 36.8% (95%CI: 20.4-66.4) for non-responding pts (p<0.001). Of the pts who relapsed after response, 1 had major path response (<10% vital tumor) and 1 a partial response (10-15% vital tumor). Estimated 3-year RFS and OS rates are presented in the Table. Conclusions: Updated data from OpACIN and OpaCIN-neo trials confirm the durability of responses upon neoadjuvant combination checkpoint inhibition in high risk stage III melanoma. Pathologic response remains a reliable surrogate marker for RFS and OS. Clinical trial information: NCT02437279, NCT02977052. [Table: see text]

Neo-adjuvant T-VEC plus nivolumab combination therapy for resectable early-stage or metastatic (IIIB-IVM1a) melanoma with injectable disease: The NIVEC trial

TPS9607

Background: The prognosis of patients with melanoma is significantly correlated with disease stage and has greatly improved with the introduction of the currently approved therapies. Trials investigating neo-adjuvant treatment with immune checkpoint inhibitors (ICI) have shown high pathologic response rates up to 25-80%, however, still a large group of patients derive no (durable) clinical benefit. Treatment with talimogene laherparepvec (T-VEC), a modified herpes simplex virus type-1, is approved for patients with unresectable stage IIIB-IVM1a melanoma, with high and durable response rates and a mild toxicity profile. Earlier trials have suggested that T-VEC has the capacity to heighten the immune response and to elicit an abscopal effect in melanoma when given in combination with ICI. Combination ICI and intralesional T-VEC has already been investigated in patients with unresectable stage IIIB-IV disease, however, no data is available yet on the potential benefit of this combination therapy in neo-adjuvant setting. This is the first trial investigating the efficacy and safety of neo-adjuvant treatment of T-VEC in combination with nivolumab (anti-PD-1 antibody), followed by surgical resection in patients with resectable stage IIIB-IVM1a melanoma, with the potential of high pathologic response rates and acceptable toxicity. Methods: In this single center, single arm, phase II study, a total of 24 patients ≥18 years of age and a good clinical performance score with treatment naïve, stage IIIB-IVM1a melanoma (AJCC 8th edition) with injectable disease and resectable (sub)cutaneous satellite or in-transit metastases and/or tumor positive lymph nodes, will be included. Patients will receive four courses of T-VEC up to 4mL (first dose as seroconversion dose) and three doses of nivolumab (240mg flatdose) every two weeks, followed by surgical resection in week nine. The primary endpoint of this trial is pathologic response rate, with the aim to show a high major pathologic (near-complete or complete) response rate up to 45%. Secondary endpoints are safety according to CTCAE v5.0, the rate of delay of surgery and event free survival. Additionally, prognostic and predictive biomarker research and health-related quality of life evaluation will be performed. Enrollment started in June 2020 in the Netherlands Cancer Institute, with currently 13 of the 24 planned patients treated. Clinical trial information: NCT04330430.