Efficacy and safety of lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, in patients with advanced melanoma after progression on immune checkpoint inhibitors and targeted therapies: pooled analysis of consecutive cohorts of the C-144-01 study

BACKGROUND

Patients with advanced melanoma have limited treatment options after progression on immune checkpoint inhibitors (ICI). Lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, demonstrated an investigator-assessed objective response rate (ORR) of 36% in 66 patients who progressed after ICI and targeted therapy. Herein, we report independent review committee (IRC)-assessed outcomes of 153 patients treated with lifileucel in a large multicenter Phase 2 cell therapy trial in melanoma.

METHODS

Eligible patients had advanced melanoma that progressed after ICI and targeted therapy, where appropriate. Melanoma lesions were resected (resected tumor diameter ≥1.5 cm) and shipped to a central good manufacturing practice facility for 22-day lifileucel manufacturing. Patients received a non-myeloablative lymphodepletion regimen, a single lifileucel infusion, and up to six doses of high-dose interleukin-2. The primary endpoint was IRC-assessed ORR (Response Evaluation Criteria in Solid Tumors V.1.1).

RESULTS

The Full Analysis Set consisted of 153 patients treated with lifileucel, including longer-term follow-up on the 66 patients previously reported. Patients had received a median of 3.0 lines of prior therapy (81.7% received both anti-programmed cell death protein 1 and anti-cytotoxic lymphocyte-associated protein 4) and had high disease burden at baseline (median target lesion sum of diameters (SOD): 97.8 mm; lactate dehydrogenase (LDH) >upper limit of normal: 54.2%). ORR was 31.4% (95% CI: 24.1% to 39.4%), with 8 complete responses and 40 partial responses. Median duration of response was not reached at a median study follow-up of 27.6 months, with 41.7% of the responses maintained for ≥18 months. Median overall survival and progression-free survival were 13.9 and 4.1 months, respectively. Multivariable analyses adjusted for Eastern Cooperative Oncology Group performance status demonstrated that elevated LDH and target lesion SOD >median were independently correlated with ORR (p=0.008); patients with normal LDH and SOD <median had greater likelihood of response than those with either (OR=2.08) or both (OR=4.42) risk factors. The most common grade 3/4 treatment-emergent adverse events (≥30%) were thrombocytopenia (76.9%), anemia (50.0%), and febrile neutropenia (41.7%).

CONCLUSIONS

Investigational lifileucel demonstrated clinically meaningful activity in heavily pretreated patients with advanced melanoma and high tumor burden. Durable responses and a favorable safety profile support the potential benefit of one-time lifileucel TIL cell therapy in patients with limited treatment options in ICI-refractory disease.

First-in-human study of an OX40 (ivuxolimab) and 4-1BB (utomilumab) agonistic antibody combination in patients with advanced solid tumors

BACKGROUND

Ivuxolimab (PF-04518600) and utomilumab (PF-05082566) are humanized agonistic IgG2 monoclonal antibodies against OX40 and 4-1BB, respectively. This first-in-human, multicenter, open-label, phase I, dose-escalation/dose-expansion study explored safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor activity of ivuxolimab+utomilumab in patients with advanced solid tumors.

METHODS

Dose-escalation: patients with advanced bladder, gastric, or cervical cancer, melanoma, head and neck squamous cell carcinoma, or non-small cell lung cancer (NSCLC) who were unresponsive to available therapies, had no standard therapy available or declined standard therapy were enrolled into five dose cohorts: ivuxolimab (0.1-3 mg/kg every 2 weeks (Q2W)) intravenously plus utomilumab (20 or 100 mg every 4 weeks (Q4W)) intravenously. Dose-expansion: patients with melanoma (n=10) and NSCLC (n=20) who progressed on prior anti-programmed death receptor 1/programmed death ligand-1 and/or anti-cytotoxic T-lymphocyte-associated antigen 4 (melanoma) received ivuxolimab 30 mg Q2W intravenously plus utomilumab 20 mg Q4W intravenously. Adverse events (AEs) were graded per National Cancer Institute Common Terminology Criteria for Adverse Events V.4.03 and efficacy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST) V.1.1 and immune-related RECIST (irRECIST). Paired tumor biopsies and whole blood were collected to assess pharmacodynamic effects and immunophenotyping. Whole blood samples were collected longitudinally for immunophenotyping.

RESULTS

Dose-escalation: 57 patients were enrolled; 2 (3.5%) patients with melanoma (0.3 mg/kg+20 mg and 0.3 mg/kg+100 mg) achieved partial response (PR), 18 (31.6%) patients achieved stable disease (SD); the disease control rate (DCR) was 35.1% across all dose levels. Dose-expansion: 30 patients were enrolled; 1 patient with NSCLC achieved PR lasting &gt;77 weeks. Seven of 10 patients with melanoma (70%) and 7 of 20 patients with NSCLC (35%) achieved SD: median (range) duration of SD was 18.9 (13.9-49.0) weeks for the melanoma cohort versus 24.1 (14.3-77.9+) weeks for the NSCLC cohort; DCR (NSCLC) was 40%. Grade 3-4 treatment-emergent AEs were reported in 28 (49.1%) patients versus 11 (36.7%) patients in dose-escalation and dose-expansion, respectively. There were no grade 5 AEs deemed attributable to treatment. Ivuxolimab area under the concentration-time curve increased in a dose-dependent manner at 0.3-3 mg/kg doses.

CONCLUSIONS

Ivuxolimab+utomilumab was found to be well tolerated and demonstrated preliminary antitumor activity in selected groups of patients.

TRIAL REGISTRATION NUMBER

NCT02315066.

Perspectives in Melanoma: meeting report from the Melanoma Bridge (December 2nd - 4th, 2021, Italy)

Advances in immune checkpoint and combination therapy have led to improvement in overall survival for patients with advanced melanoma. Improved understanding of the tumor, tumor microenvironment and tumor immune-evasion mechanisms has resulted in new approaches to targeting and harnessing the host immune response. Combination modalities with other immunotherapy agents, chemotherapy, radiotherapy, electrochemotherapy are also being explored to overcome resistance and to potentiate the immune response. In addition, novel approaches such as adoptive cell therapy, oncogenic viruses, vaccines and different strategies of drug administration including sequential, or combination treatment are being tested. Despite the progress in diagnosis of melanocytic lesions, correct classification of patients, selection of appropriate adjuvant and systemic theràapies, and prediction of response to therapy remain real challenges in melanoma. Improved understanding of the tumor microenvironment, tumor immunity and response to therapy has prompted extensive translational and clinical research in melanoma. There is a growing evidence that genomic and immune features of pre-treatment tumor biopsies may correlate with response in patients with melanoma and other cancers, but they have yet to be fully characterized and implemented clinically. Development of novel biomarker platforms may help to improve diagnostics and predictive accuracy for selection of patients for specific treatment. Overall, the future research efforts in melanoma therapeutics and translational research should focus on several aspects including: (a) developing robust biomarkers to predict efficacy of therapeutic modalities to guide clinical decision-making and optimize treatment regimens, (b) identifying mechanisms of therapeutic resistance to immune checkpoint inhibitors that are potentially actionable, (c) identifying biomarkers to predict therapy-induced adverse events, and (d) studying mechanism of actions of therapeutic agents and developing algorithms to optimize combination treatments. During the Melanoma Bridge meeting (December 2nd-4th, 2021, Naples, Italy) discussions focused on the currently approved systemic and local therapies for advanced melanoma and discussed novel biomarker strategies and advances in precision medicine as well as the impact of COVID-19 pandemic on management of melanoma patients.

Efficacy of anti-PD-1 and ipilimumab alone or in combination in acral melanoma

BACKGROUND

Acral melanoma is a rare melanoma subtype with poor prognosis. Importantly, these patients were not identified as a specific subgroup in the landmark melanoma trials involving ipilimumab and the anti-programmed cell death protein-1 (PD-1) agents nivolumab and pembrolizumab. There is therefore an absence of prospective clinical trial evidence regarding the efficacy of checkpoint inhibitors (CPIs) in this population. Acral melanoma has lower tumor mutation burden (TMB) than other cutaneous sites, and primary site is associated with differences in TMB. However the impact of this on the effectiveness of immune CPIs is unknown. We examined the efficacy of CPIs in acral melanoma, including by primary site.

METHODS

Patients with unresectable stage III/IV acral melanoma treated with CPI (anti-PD-1 and/or ipilimumab) were studied. Multivariable logistic and Cox regression analyses were conducted. Primary outcome was objective response rate (ORR); secondary outcomes were progression-free survival (PFS) and overall survival (OS).

RESULTS

In total, 325 patients were included: 234 (72%) plantar, 69 (21%) subungual and 22 (7%) palmar primary sites. First CPI included: 184 (57%) anti-PD-1, 59 (18%) anti-PD-1/ipilimumab combination and 82 (25%) ipilimumab. ORR was significantly higher with initial anti-PD-1/ipilimumab compared with anti-PD-1 (43% vs 26%, HR 2.14, p=0.0004) and significantly lower with ipilimumab (15% vs 26%, HR 0.49, p=0.0016). Landmark PFS at 1 year was highest for anti-PD-1/ipilimumab at 34% (95% CI 24% to 49%), compared with 26% (95% CI 20% to 33%) with anti-PD-1 and 10% (95% CI 5% to 19%) with ipilimumab. Despite a trend for increased PFS, anti-PD-1/ipilimumab combination did not significantly improve PFS (HR 0.85, p=0.35) or OS over anti-PD-1 (HR 1.30, p=0.16), potentially due to subsequent therapies and high rates of acquired resistance. No outcome differences were found between primary sites.

CONCLUSION

While the ORR to anti-PD-1/ipilimumab was significantly higher than anti-PD-1 and PFS numerically higher, in this retrospective cohort this benefit did not translate to improved OS. Future trials should specifically include patients with acral melanoma, to help determine the optimal management of this important melanoma subtype.

Optimal systemic therapy for high-risk resectable melanoma

Immunotherapy with immune-checkpoint inhibitors and molecularly targeted therapy with BRAF inhibitors were pioneered in the setting of advanced-stage, unresectable melanoma, where they revolutionized treatment and considerably improved patient survival. These therapeutic approaches have also been successfully transitioned into the resectable disease setting, with the regulatory approvals of ipilimumab, pembrolizumab, nivolumab, and dabrafenib plus trametinib as postoperative (adjuvant) treatments for various, overlapping groups of patients with high-risk melanoma. Moreover, these agents have shown variable promise when used in the preoperative (neoadjuvant) period. The expanding range of treatment options available for resectable high-risk melanoma, all of which come with risks as well as benefits, raises questions over selection of the optimal therapeutic strategy and agents for each individual, also considering that many patients might be cured with surgery alone. Furthermore, the use of perioperative therapy has potentially important implications for the management of patients who have disease recurrence. In this Viewpoint, we asked four expert investigators and medical or surgical oncologists who have been involved in the key studies of perioperative systemic therapies for their perspectives on the optimal management of patients with high-risk melanoma.

Endocrine Autoantibodies Determine Immune Checkpoint Inhibitor-induced Endocrinopathy: A Prospective Study

CONTEXT

Incidence and awareness of endocrine-related adverse events (ERAE) associated with use of immune checkpoint inhibitors (ICI) has grown with increased ICI use, yet mechanisms for ERAE prediction, surveillance, and development are not well established.

OBJECTIVE

We prospectively evaluated the impact of endocrine autoimmunity on ERAE development and overall survival (OS).

METHODS

Adults ≥ 18 years of age prescribed ICI treatment for advanced or metastatic solid tumors and no known active/past endocrine disorders were eligible for enrollment. Thyroid, adrenal, and pancreatic antibodies as well as hormone levels were assessed prior to ICI treatment and at 8 to 9 weeks and 36 weeks after treatment for ERAE in relation to presence and changes in endocrine-specific antibodies, hormone levels, and OS.

RESULTS

Sixty patients were enrolled and ERAE were detected in 14 (23.3%), with a median onset of 52 days (IQR, 38.5-71.5) after first ICI dose. Hypothyroidism occurred in 12 (20%) patients, and 2 (3.33%) patients developed hypophysitis. Diabetes and primary adrenal insufficiency were not observed. Antibodies were detected in 14 patients (11 at baseline, 3 developed during follow-up) and their presence was significantly associated with ERAE (R2 59.3%, P < 0.001). Thyroid peroxidase antibody (20%) and thyroid-stimulating immunoglobulin (3.3%) were most common, and anti-GAD was present in 1 patient. The presence of ERAE was associated with a more favorable OS (P = 0.001).

CONCLUSION

Endocrine-specific autoantibodies play an important role in ERAE pathogenesis and may serve as predictive markers for early identification and treatment of ICI-induced endocrinopathies.

Abstract CT183: First-in-human study of MEDI1191 (mRNA encoding IL-12) plus durvalumab in patients (pts) with advanced solid tumors

Background: IL-12 is a key mediator of antitumor immune response. In preclinical models, IT IL-12 mRNA led to IFNγ release and CD8+ T cell-dependent tumor regression and potentiated PD-L1 blockade. MEDI1191, a lipid nanoparticle-formulated mRNA encoding IL-12 delivered by IT injection, drives IL-12 production and enhances antitumor immune response with improved tolerability. We hypothesized that combining MEDI1191 with PD-L1 blockade would augment antitumor immunity in vivo. Here we report updated results from the dose-escalation phase of the first-in-human study of IT MEDI1191 and IV durvalumab (D; anti-PD-L1) for advanced/metastatic solid tumors (NCT03946800).

Methods: In this multicenter, open-label study, MEDI1191 was dosed sequentially (seq, Part 1A) or concurrently (conc, Part 1B) with D. In Part 1A, MEDI1191 was given IT on Days 1 and 22 followed by D 1500 mg on day 43 and then Q4W IV. In Part 1B, MEDI1191 was given IT on Days 1, 29, 57 and then Q8W, along with D on Day 1 and then Q4W. Treatment continued until progression or unacceptable toxicity for up to 2 years. Eligible adult pts had any solid tumor with cutaneous or subcutaneous lesions suitable for IT injection and progression on standard therapy for recurrent/metastatic disease. Primary objectives were safety and tolerability and determination of maximum tolerated dose (MTD); secondary objectives included preliminary antitumor activity by RECIST v1.1.

Results: Starting in May 2019, 31 pts received seq MEDI1191 with D (Part 1A cohorts 0.1-12 μg; n=20) or conc MEDI1191 with D (Part 1B cohorts 1.0-3.0 μg; n=11); 23 pts had received prior anti-PD-1/PD-L1 therapy. Most common tumor types were melanoma, n=8; head and neck cancer, n=4; and breast cancer, n=4. At the data cutoff of Dec 7, 2021, there were no dose-limiting toxicities and no MTD was identified. One pt (3.2%) had a Gr ≥3 MEDI1191-related AE (Gr 3 pyrexia, resolved within 24 hr) and 1 (3.2%) had a MEDI1191-related serious AE (SAE; Gr 2 confusion). Two pts had Gr 3 D-related AEs (6.5%, pyrexia also related to MEDI1191 and pruritus; each n=1); none had a D-related SAE. There were no Gr 4 related AEs. 3 pts had partial responses (PR): 1 with head and neck cancer (unconfirmed, off study) and 2 with anti-PD-1 resistant melanoma (1 confirmed, &gt;12 months on treatment; 1 unconfirmed, off study); 10 pts had stable disease (including the 2 unconfirmed PRs). Among pts with available biomarker data (up to 3 μg in Part 1A and 1 μg in Part 1B), MEDI1191 increased serum IL-12 in 15/17 pts, increased CD8+ T cell tumor infiltration by &gt;2-fold in 8/14 pts and increased tumor PD-L1 expression in 6/14 pts.

Conclusions: IT MEDI1191 plus systemic anti-PD-L1 was safe and feasible. Preliminary antitumor efficacy and pharmacodynamics, including tumor CD8+ T cell recruitment, were consistent with expected mechanism of action. Pts with injectable deep visceral and superficial lesions are being recruited.

Citation Format: Benedito A. Carneiro, Dmitriy Zamarin, Thomas Marron, Inderjit Mehmi, Sandip P. Patel, Vivek Subbiah, Anthony El-Khoueiry, David Grand, Kirema Garcia-Reyes, Sanjay Goel, Phillip Martin, Jixin Wang, Yuling Wu, Steven Eck, Benjamin Ridgway, Nairouz Elgeioushi, Jim Eyles, Nicholas Durham, Analia Azaro, Omid Hamid. First-in-human study of MEDI1191 (mRNA encoding IL-12) plus durvalumab in patients (pts) with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT183.

Single-agent anti-PD-1 or combined with ipilimumab in patients with mucosal melanoma: an international, retrospective, cohort study

BACKGROUND

Mucosal melanoma (MM) is a rare melanoma subtype with distinct biology and poor prognosis. Data on the efficacy of immune checkpoint inhibitors (ICIs) is limited. We determined the efficacy of ICIs in MM, analysed by primary site and ethnicity/race.

PATIENTS AND METHODS

Retrospective cohort study from 25 cancer centres in Australia, Europe, USA and Asia. Patients with histologically confirmed MM were treated with anti-PD1+/-ipilimumab. Primary endpoints were response rate (RR), progression-free survival (PFS), overall survival (OS) by primary site (naso-oral, urogenital, anorectal, other), ethnicity/race (Caucasian, Asian, Other) and treatment. Univariate and multivariate Cox proportional hazard model analyses were conducted.

RESULTS

In total, 545 patients were included: 331 (63%) Caucasian, 176 (33%) Asian and 20 (4%) Other. Primary sites included 113 (21%) anorectal, 178 (32%) urogenital, 206 (38%) naso-oral and 45 (8%) other. 348 (64%) received anti-PD1 and 197 (36%) anti-PD1/ipilimumab. RR, PFS and OS did not differ by primary site, ethnicity/race or treatment. RR for naso-oral was numerically higher for anti-PD1/ipilimumab (40%, 95% CI 29-54%) compared with anti-PD1 (29%, 95% CI 21-37%). 35% of patients that initially responded progressed. Median duration of response (mDOR) was 26 months (95% CI 18-NR [Not Reached]). Factors associated with short PFS were ECOG PS ≥3 (p<0.01), LDH >ULN (p=0.01), lung metastases (p<0.01) and ≥1 previous treatments (p<0.01). Factors associated with short OS were ECOG PS ≥1 (p<0.01), LDH >ULN (p=0.03), lung metastases (p<0.01) and ≥1 previous treatments (p<0.01).

CONCLUSIONS

MM has poor prognosis. Treatment efficacy of anti-PD1+/-ipilimumab was similar and did not differ by ethnicity/race. Naso-oral primaries had numerically higher response to anti-PD1/ipilimumab, without difference in survival. The addition of ipilimumab did not show greater benefit over anti-PD1 for other primary sites. In responders, mDOR was short and acquired resistance was common. Other factors, including site and number of metastases were associated with survival.

Safety and efficacy of etigilimab in combination with nivolumab in select recurrent/advanced solid tumors

2651

Background: Etigilimab (etig), a humanized IgG1 monoclonal antibody, blocks TIGIT interaction with PVR (poliovirus receptor) and inhibits downstream signalling with target cell killing. Etig +/- nivolumab (nivo) showed acceptable safety and preliminary activity in a FIH Phase 1a/b study in solid tumors. ACTIVATE, an open-label Phase 1b/2 basket study is evaluating further efficacy, safety, tolerability and PK/PD of etig+nivo. This is a preliminary efficacy and safety analysis from ACTIVATE. Methods: Subjects with advanced/metastatic solid tumors without curative/standard of care therapies are given IV etig+nivo Q2W until disease progression or intolerable toxicity. Six open cohorts are enrolling in parallel: endometrial cancer (post-front-line platinum), endometrial cancer (2-3 prior lines), PD-L1+ checkpoint-inhibitor-naïve (CPI-n) cervical cancer, rare cancers (germ cell tumor (GCT), sarcoma, uveal melanoma), ovarian cancer (post-front-line platinum) and TMB-h/MSS, (TMB >10mut/mb) tumors. Tumor assessments are done every 8 weeks following baseline scan. Primary endpoint is investigator-assessed ORR by RECIST 1.1. Secondary endpoints include duration of response and safety. Results: Of 27 efficacy-evaluable subjects enrolled in the 6 open cohorts with minimum 1 staging scan or radiological/clinical progression at data cut-off of 02/10/22, 12 had clinical benefit with 1 complete response (CR), 2 partial responses (PRs) and 9 stable diseases (SDs) and 15 had radiological/clinical progressive disease (PD), with an overall response rate (ORR) of 11% and disease control rate (DCR) of 44%. Conclusions: Etig+nivo is safe and well tolerated with no new safety signals. Early efficacy was noted in cervical cancer (1CR, 1PR and 1SD) and uveal melanoma (3 SDs >20 weeks). Encouraging activity was also noted in ovarian cancer and post-CPI treated TMB-H/MSS NSCLC. These early data support continued evaluation of the combination of etig+nivo. Clinical activity was notable as below. Clinical trial information: NCT04761198. [Table: see text]

Pembrolizumab (pembro) plus dabrafenib (dab) and trametinib (tram) in BRAFV600E/K-mutant melanoma: Long-term follow-up of KEYNOTE-022 parts 1, 2, and 3

9516

Background: KEYNOTE-022 (NCT02130466) was a phase 1/2 study of pembro + dab + tram or pembro + tram in patients (pts) with unresectable stage III/IV melanoma (parts 1-3) or solid tumors (parts 4 and 5). In previous analyses of pts with BRAFV600E/K -mutant melanoma, pembro + dab + tram was shown to have manageable safety in parts 1-3, albeit with a higher incidence of TRAEs in part 3, and substantially improved PFS, DOR, and OS vs placebo + dab + tram in part 3, although the primary end point of a statistically significant improvement in PFS was not met. Long-term follow-up of pts with BRAFV600E/K-mutant melanoma in parts 1-3 are presented. Methods: Eligible pts were ≥18 y with unresectable stage III/IV BRAFV600E/K-mutant melanoma, ≥1 measurable lesion per RECIST v1.1, ECOG PS 0/1, and no prior systemic therapy for advanced disease. In parts 1 and 2, which involved dose finding and confirmation, pts received pembro 2 mg/kg IV Q3W + dab 150 mg PO BID + tram 2 mg PO QD (MTD). In part 3, pts were randomized 1:1 to pembro + dab + tram at MTD or placebo + dab + tram. Primary end points were safety, tolerability, and MTD (parts 1 and 2); ORR per RECIST v1.1 by investigator review (part 2); and PFS per RECIST v1.1 by investigator review (part 3). Data cutoff was July 14, 2021. Results: Median (range) study follow-up was 72.9 mo (68.4-84.5) in parts 1 and 2 (n = 15) and 61.2 mo (50.7-67.5) for all pts (n = 120; 60 each arm) in part 3. Safety of pembro + dab + tram in parts 1 and 2 was consistent with prior reports; grade 3/4 TRAEs occurred in 11 pts (73%), and no additional DLTs occurred. ORR in parts 1 and 2 was 67% (95% CI, 38-88), which was similar to that reported at an earlier data cut (73% [95% CI, 45-92]); median DOR was 19.4 mo (95% CI, 2.8-NR), median OS was NR (95% CI, 10.3-NR), 48-mo OS rate was 60%, median PFS was 15.2 mo (95% CI, 4.2-NR), and 48-mo PFS rate was 28% (Ribas A et al. Nat Med. 2019;25:936-940). In part 3, median PFS was 17.0 mo (95% CI, 11.3-NR) for pembro + dab + tram vs 9.9 mo (95% CI, 6.7-15.6) for placebo + dab + tram (HR, 0.46; 95% CI, 0.29-0.74) and 24-mo PFS rate was 47% vs 16%, and median OS was 46.3 mo (95% CI, 23.9-NR) vs 26.3 mo (95% CI, 18.2-38.6); and 24-mo OS rate was 63% vs 52%, respectively. ORR was 65% (95% CI, 52-77) for pembro + dab + tram vs 72% (95% CI, 59-83) for placebo + dab + tram; median DOR was 30.2 mo (95% CI, 14.1-NR) vs 12.1 mo (95% CI, 6.0-15.7). Safety in part 3 was similar to prior reports; grade 3-5 TRAEs occurred in 42 pts (70%) in the pembro + dab + tram arm vs 27 pts (45%) in the placebo + dab + tram arm (Ferrucci PF et al. J Immunother Cancer. 2020;8:e001806). No additional grade 5 TRAEs occurred (1 grade 5 pneumonitis had occurred at prior analysis). Conclusions: At long-term follow-up, first-line pembro + dab + tram continued to show improved PFS, DOR, and OS compared with placebo + dab + tram in pts with BRAFV600E/K-mutant melanoma. TRAEs were more common with pembro + dab + tram but no new safety signals were identified. Clinical trial information: NCT02130466.

ARTISTRY-6: Nemvaleukin alfa monotherapy in patients with advanced mucosal and cutaneous melanoma

TPS9609

Background: Despite improved outcomes for melanoma patients with the introduction of checkpoint inhibitors (CPIs), ̃50% of patients do not respond. A subset of responders ultimately progress and have limited treatment options, underscoring a high unmet need for novel treatments with durable benefit. Patients with mucosal melanoma exhibit response rates and progression-free survival times ̃2 times lower than those with cutaneous melanoma. Nemvaleukin alfa (nemvaleukin, ALKS 4230) is a novel, engineered cytokine that selectively binds the intermediate-affinity interleukin-2 receptor complex to preferentially activate CD8+ T and NK cells with minimal expansion of regulatory T cells. Nemvaleukin has been granted Orphan Drug designation for the treatment of mucosal melanoma by the FDA. In ARTISTRY-1, the intravenous (IV) recommended phase 2 dose (RP2D) of 6 µg/kg nemvaleukin monotherapy demonstrated durable antitumor activity in patients with advanced melanoma, including mucosal melanoma, previously treated with a CPI. In ARTISTRY-2, the subcutaneous (SC) RP2D of 3 mg q7d was identified demonstrating pharmacodynamic effects consistent with IV delivery. Data support further evaluation of nemvaleukin monotherapy among patients with advanced mucosal and cutaneous melanoma. Methods: ARTISTRY-6 is a phase 2, global, multicenter, open-label study. Eligible patients have had prior treatment with an anti–PD-(L)1 therapy with or without anti–CTLA-4 therapy and have an ECOG performance status of 0 or 1 and adequate hematologic reserve and hepatic and renal function. Patients with advanced cutaneous (Cohort 1) and mucosal (Cohort 2) melanoma will receive nemvaleukin at the SC and IV RP2D, respectively. Patients will receive nemvaleukin until progression or intolerable toxicity. The primary objective is to evaluate the antitumor activity of nemvaleukin monotherapy defined by overall response rate. Additional objectives include the evaluation of safety, health-related quality of life, predictive biomarkers, pharmacokinetics, immunogenicity, and pharmacodynamic effects. Clinical trial information: NCT04830124.

DELTA-1: A global, multicenter, phase 2 study of ITIL-168, an unrestricted autologous tumor-infiltrating lymphocyte (TIL) cell therapy, in adult patients with advanced cutaneous melanoma

TPS9594

Background: Patients (pts) with advanced (unresectable or metastatic) cutaneous melanoma and persistent disease after checkpoint inhibitor therapy have poor outcomes and limited treatment options, highlighting a significant unmet medical need (Schadendorf D et al. Lancet. 2018;392:971-984). Investigational autologous TIL cell therapies have shown promise in this population, partly attributable to their intrinsic and patient-specific antitumor activity (Borch TH et al. J Immunother Cancer. 2020;8:e000668). Made from each patient’s digested and cryopreserved tumor, ITIL-168 is an autologous TIL cell therapy manufactured to offer an unrestricted T-cell receptor repertoire. A single-center, compassionate use clinical series demonstrated the feasibility and clinical utility of an earlier version of ITIL-168, with a high overall response rate among pts previously treated with PD-1 inhibitor (PD-1i) therapy (58%, n = 12; Pillai M et al. Ann Oncol. 2021;32[suppl 5]:S882). DELTA-1 (NCT05050006) is a global, multicenter phase 2 study to evaluate efficacy and safety of ITIL-168 in pts with cutaneous melanoma relapsed or refractory to a PD-1i, pts intolerant to a PD-1i, and pts whose current best response to a PD-1i is stable disease. Methods: Pts aged ≥18 years with histologically confirmed advanced cutaneous melanoma, ECOG performance status 0-1, and adequate organ function will be enrolled in 1 of 3 cohorts. Cohort 1 (n≈80) will include pts who relapsed after or were refractory to ≥1 prior line of systemic therapy, including a PD-1i and, if BRAF-mutated, a BRAFi ± MEKi. Cohorts 2 and 3 (n≈25 each) will include pts intolerant to PD-1i and those with stable disease after ≥4 doses of PD-1i, respectively. After tumor resection for TIL harvest, pts must have ≥1 remaining measurable lesion per RECIST 1.1. Pts with uveal, acral, or mucosal melanoma, prior allogeneic transplant or cell therapy, and with central nervous system (CNS) disorder or symptomatic and/or untreated CNS metastases are ineligible. Pts will receive 5 days of lymphodepleting chemotherapy (cyclophosphamide ×2 days overlapping with fludarabine ×5 days) followed by a single ITIL-168 infusion (≥5×109 cells) and supportive short-course, high-dose IL-2. The primary endpoint is objective response rate (ORR) per central review. Secondary endpoints include duration of response, progression-free survival, overall survival, disease control rate, TIL persistence, and safety. Hypothesis testing of ORR will be performed for cohort 1. The primary analysis will occur when all pts in the cohort 1 modified intent-to-treat population have been followed for ≥6 months after the first posttreatment disease assessment. DELTA-1 opened for enrollment in September 2021. Updated site information will be given at the time of presentation. Clinical trial information: NCT05050006.

Updated overall survival (OS) data from the phase 1b study of tebentafusp (tebe) as monotherapy or combination therapy with durvalumab (durva) and/or tremelimumab (treme) in metastatic cutaneous melanoma (mCM)

104

Background: Tebe is a T-cell receptor bispecific (gp100 x CD3) against gp100 peptide-HLA-A2 complexes that are overexpressed in uveal (UM)/cutaneous melanoma (CM). Tebe is the only therapy to show an OS benefit (HR 0.51) in a phase (Ph) 3 trial in previously untreated metastatic UM. In a prior Ph 1 trial, tebe demonstrated monotherapy activity in anti-PD1 naïve mCM (1-yr OS, approx. 74%). The safety and initial activity of tebe with dose escalation of durva and/or treme in previously treated mCM has been reported. Here, we present updated OS in the subset of mCM patients (pts) relapsed or refractory to prior anti-PD1, a population where recent reports suggest a benchmark 1-yr OS of approximately 55% and median OS of approximately 14 months (mos). Methods: Patients with HLA-A2+, pre-treated mCM received weekly tebe (IV) monotherapy in Arm 4a or in combination with dose escalation of durva and/or treme (IV) on day 15 of each cycle (Arms 1-3). Primary objective was RP2D, secondary objectives were safety and efficacy. Subgroup analyses were performed for durva doses ≥10 mg/kg, a threshold previously defined by Bavarel et al, 2018. Analysis performed on data cut-off 04 January 2022 with median follow up for 14.3 mos. [NCT02535078] Results: 112 pts were treated with median age 59, 23% were ECOG = 1, 37% were BRAFm (73% received prior BRAFi/MEKi), 55% had LDH > ULN. 92% of pts were 2L+ and 74% 3L+; median 3 prior lines. The safety profile of all therapy arms within this study therapy remains very favorable with no new safety signals identified. 97 of 112 pts were documented as relapsed or refractory to prior anti-PD1 (80% also received ipilimumab). Of these 97 pts, 32 received tebe + durva (Arm 1), 13 received tebe + treme (Arm 2), 26 received triplet therapy (Arm 3), and 20 received tebe monotherapy (Arm 4a). 33 of 97 pts in any arm received durva ≥ 10 mg/kg with 1-yr OS of 79%, 2-yr OS of 34%, and median OS of 20 mos. 64 of 97 pts received durva < 10 mg/kg with 1-yr OS of 53%, 2-yr OS of 24%, and median OS of 13 mos. Tebe + durva doublet therapy had similar OS to triplet therapy with tebe + durva + treme: 1-yr OS of 74% vs. 76%, and 2-yr OS of 32% vs. 27%, respectively. Conclusions: Promising OS is seen in mCM similar to mUM, with both tumor types overexpressing gp100. In mCM relapsed or refractory to prior anti-PD1, tebe with anti–PD-L1 continues to demonstrate promising OS (1-yr, approx. 75%) compared to recent benchmarks (1-yr, approx. 55%). These data provide rationale for a randomized study of tebe with anti-PD(L)1 in mCM. Clinical trial information: NCT02535078.

The "Great Debate" at Immunotherapy Bridge 2021, December 1st-2nd, 2021

As part of the 2021 Immunotherapy Bridge virtual congress (December 1–2, Naples, Italy), the Great Debate sessions featured experts who were assigned counter opposing views on four important questions in immunotherapy today. The first topic was whether oncolytic viruses or other specific immunomodulators were the more promising approach for intralesional therapy. The second was whether early surrogate endpoints, such as response rate or progression-free survival, correlate with long-term overall survival was considered. Thirdly, whether vaccines can transform cold into hot tumors was discussed and, finally, broad versus deep analytic profiling approaches to gain insights into immune-oncology development were compared. As with previous Bridge congresses, presenters were invited by the meeting Chairs and positions taken during the debates may not have reflected their respective personal view. In addition, the views summarised in this article are based on available evidence but may reflect personal interpretation of these data, clinical experience and subjective opinion of the speaker.

A Phase I, Open-Label, Dose-Escalation Study of the OX40 Agonist Ivuxolimab in Patients with Locally Advanced or Metastatic Cancers

PURPOSE

Stimulation of effector T cells is an appealing immunotherapeutic approach in oncology. OX40 (CD134) is a costimulatory receptor expressed on activated CD4⁺ and CD8⁺ T cells. Induction of OX40 following antigen recognition results in enhanced T-cell activation, proliferation, and survival, and OX40 targeting shows therapeutic efficacy in preclinical studies. We report the monotherapy dose-escalation portion of a multicenter, phase I trial (NCT02315066) of ivuxolimab (PF-04518600), a fully human immunoglobulin G2 agonistic monoclonal antibody specific for human OX40.

PATIENTS AND METHODS

Adult patients (N = 52) with selected locally advanced or metastatic cancers received ivuxolimab 0.01 to 10 mg/kg. Primary endpoints were safety and tolerability. Secondary/exploratory endpoints included preliminary assessment of antitumor activity and biomarker analyses.

RESULTS

The most common all-causality adverse events were fatigue (46.2%), nausea (28.8%), and decreased appetite (25.0%). Of 31 treatment-related adverse events, 30 (96.8%) were grade ≤2. No dose-limiting toxicities occurred. Ivuxolimab exposure increased in a dose-proportionate manner from 0.3 to 10 mg/kg. Full peripheral blood target engagement occurred at ≥0.3 mg/kg. Three (5.8%) patients achieved a partial response, and disease control was achieved in 56% of patients. Increased CD4⁺ central memory T-cell proliferation and activation, and clonal expansion of CD4⁺ and CD8⁺ T cells in peripheral blood were observed at 0.1 to 3.0 mg/kg. Increased immune cell infiltrate and OX40 expression were evident in on-treatment tumor biopsies.

CONCLUSIONS

Ivuxolimab was generally well tolerated with on-target immune activation at clinically relevant doses, showed preliminary antitumor activity, and may serve as a partner for combination studies.

Clinical and molecular response to tebentafusp in previously treated patients with metastatic uveal melanoma: a phase 2 trial

In patients with previously treated metastatic uveal melanoma, the historical 1 year overall survival rate is 37% with a median overall survival of 7.8 months. We conducted a multicenter, single-arm, open-label phase 2 study of tebentafusp, a soluble T cell receptor bispecific (gp100×CD3), in 127 patients with treatment-refractory metastatic uveal melanoma (NCT02570308). The primary endpoint was the estimation of objective response rate based on RECIST (Response Evaluation Criteria in Solid Tumours) v1.1. Secondary objectives included safety, overall survival, progression-free survival and disease control rate. All patients had at least one treatment-related adverse event, with rash (87%), pyrexia (80%) and pruritus (67%) being the most common. Toxicity was mostly mild to moderate in severity but was greatly reduced in incidence and intensity after the initial three doses. Despite a low overall response rate of 5% (95% CI: 2-10%), the 1 year overall survival rate was 62% (95% CI: 53-70%) with a median overall survival of 16.8 months (95% CI: 12.9-21.3), suggesting benefit beyond traditional radiographic-based response criteria. In an exploratory analysis, early on-treatment reduction in circulating tumour DNA was strongly associated with overall survival, even in patients with radiographic progression. Our findings indicate that tebentafusp has promising clinical activity with an acceptable safety profile in patients with previously treated metastatic uveal melanoma, and data suggesting ctDNA as an early indicator of clinical benefit from tebentafusp need confirmation in a randomized trial.