Probing Ferryl Reactivity in a Nonheme Iron Oxygenase Using an Expanded Genetic Code.

The ability to introduce noncanonical amino acids as axial ligands in heme enzymes has provided a powerful experimental tool for studying the structure and reactivity of their FeIV=O ("ferryl") intermediates. Here, we show that a similar approach can be used to perturb the conserved Fe coordination environment of 2-oxoglutarate (2OG) dependent oxygenases, a versatile class of enzymes that employ highly-reactive ferryl intermediates to mediate challenging C-H functionalizations. Replacement of one of the cis-disposed histidine ligands in the oxygenase VioC with a less electron donating N δ-methyl-histidine (MeHis) preserves both catalytic function and reaction selectivity. Significantly, the key ferryl intermediate responsible for C-H activation can be accumulated in both the wildtype and the modified protein. In contrast to heme enzymes, where metal-oxo reactivity is extremely sensitive to the nature of the proximal ligand, the rates of C-H activation and the observed large kinetic isotope effects are only minimally affected by axial ligand replacement in VioC. This study showcases a powerful tool for modulating the coordination sphere of nonheme iron enzymes that will enhance our understanding of the factors governing their divergent activities.

Safety of immune checkpoint inhibitor rechallenge after severe immune-related adverse events: a retrospective analysis.

Immune checkpoint inhibitors (ICIs) present clinicians with the challenge of managing immune-related adverse events (irAEs), which can range from mild to severe due to immune system activation 1. While guidelines recommend discontinuing ICIs for grade 3 partial and all grade 4 irAEs, there is growing interest in rechallenging patients based on oncological outcomes, particularly for cardiovascular and neurological irAEs where data remains scarce 1,2. We retrospectively evaluated the safety of ICI rechallenge following grade 3-4 irAEs, specifically focusing on cardiovascular and neurological events, in patients discussed at our multidisciplinary immunotoxicity assessment board between 2019 and 2021. Fifteen patients were included, with a median time to severe irAE onset of 49 days. Among them, five patients experienced neurological adverse events (NAEs): aseptic meningitis (3), inflammatory polyradiculoneuropathy (1), and ophthalmoplegia (1), while one patient presented with myocarditis. Of the 15 patients retreated with ICIs after initial severe irAEs, 11 (73%) remained free of subsequent irAEs, two (13%) experienced recurrence of the initial irAE, and two (13%) developed new irAEs distinct from the initial event. The median time to event recurrence was 69 days, occurring no earlier than the initial severe irAE. In the subset analysis focusing on severe cardiovascular and neurological irAEs, rechallenge with ICIs was generally well tolerated. However, one patient treated with anti-PD1 experienced a relapse of grade 2 aseptic meningitis. Overall, our findings suggest that rechallenging with ICIs after severe irAEs, including those affecting the cardiovascular and neurological systems, may be safe, particularly after irAE regression and corticosteroid withdrawal.

Real-world outcomes of combined lenvatinib and anti-PD-1 in advanced melanoma: the Lenvamel study, a multicenter retrospective study of the French Group of Skin Cancers (Groupe de Cancérologie Cutanée).

BACKGROUND: Currently, treatment options for patients with advanced melanoma who experience failed immunotherapy or targeted therapy are lacking. Recent studies suggest the antitumor activity of combined pembrolizumab and lenvatinib in patients with advanced melanoma progressing on immunotherapy. Herein, we report the clinical outcomes of combined lenvatinib and a programmed cell death protein-1 inhibitor (PD-1) in this population. MATERIALS AND METHODS: This French multicenter real-world study was conducted between September 2020 and July 2023. The primary endpoint was the objective response rate (ORR) according to the Response Evaluation Criteria in Solid Tumours (version 1.1). Secondary variables were treatment-related adverse events (TRAEs), progression-free survival (PFS), overall survival (OS), and duration of response (DOR). RESULTS: Of the 67 patients included (median age, 69 years; median follow-up, 5.0 months), 85% had stage IV-M1c or M1d disease. The overall ORR was 28.4% (95% CI, 18%-41%), including 3 complete (4.5%) and 16 partial (23.9%) responses. Median DOR was 3.1 (interquartile range, 1.3-4.3) months. Median PFS and OS were 3.1 (95% CI, 2.5-3.7) and 9.8 (95% CI, 5.6-13.9) months, respectively. Grades 3-5 TRAEs occurred in 16 (24%) patients; common TRAEs were fatigue (43.3%), nausea/vomiting (26.8%), diarrhea (20.9%), and hypertension (20.9%). No treatment-related deaths occurred. CONCLUSION: Our real-world study demonstrates an interesting response rate and acceptable safety profile in a population with poor prognostic factors. Our data support this treatment option for refractory melanoma, as it is not approved by the Food and Drug Administration or European Medicines Agency, and highlight the need for new strategies.

Molecularly matched targeted therapy: a promising approach for refractory metastatic melanoma.

BACKGROUND: Only a fraction of patients with metastatic melanoma derive durable benefit from approved treatments. The clinical impact of personalized medicine strategies for melanoma, apart from BRAF, NRAS, or CKIT targeting, has rarely been reported. MATERIALS AND METHODS: By means of the Group of Cutaneous Oncology of the French Society of Dermatology, we retrospectively included all patients with advanced melanoma aged 18 years and older for whom molecular testing identified one or more actionable molecular alterations and who accordingly received molecularly matched therapy. We excluded patients with only BRAF, NRAS, or CKIT alterations and patients who received molecularly matched therapy for less than 15 days. RESULTS: We included 26 patients with a median follow-up of 8 months (1-54), a median age of 63 years (24-89), and a sex ratio of 2.7. These patients had been heavily pretreated, and 64% had elevated LDH levels. The disease control rate was 38%, with 4 cases of partial response (overall response rate: 15%) and 6 of stable disease for at least 6 months. The median duration of treatment was 3.1 months (0.9-13.5). Among patients with disease control, the median duration of control was 6.6 months (2.6-13.5) and 3 cases were ongoing at the end of the study. Patients with controlled disease had GNA11, MAP2K1, FYCO1-RAF1, HRAS, ATM, CCND1, MDM2/CDK4, and CDKN2A/NRAS alterations. CONCLUSIONS: High-throughput sequencing followed by matched targeted therapy is a promising approach for patients with advanced melanoma refractory to approved treatments.

A non-canonical nucleophile unlocks a new mechanistic pathway in a designed enzyme.

Directed evolution of computationally designed enzymes has provided new insights into the emergence of sophisticated catalytic sites in proteins. In this regard, we have recently shown that a histidine nucleophile and a flexible arginine can work in synergy to accelerate the Morita-Baylis-Hillman (MBH) reaction with unrivalled efficiency. Here, we show that replacing the catalytic histidine with a non-canonical Nδ-methylhistidine (MeHis23) nucleophile leads to a substantially altered evolutionary outcome in which the catalytic Arg124 has been abandoned. Instead, Glu26 has emerged, which mediates a rate-limiting proton transfer step to deliver an enzyme (BHMeHis1.8) that is more than an order of magnitude more active than our earlier MBHase. Interestingly, although MeHis23 to His substitution in BHMeHis1.8 reduces activity by 4-fold, the resulting His containing variant is still a potent MBH biocatalyst. However, analysis of the BHMeHis1.8 evolutionary trajectory reveals that the MeHis nucleophile was crucial in the early stages of engineering to unlock the new mechanistic pathway. This study demonstrates how even subtle perturbations to key catalytic elements of designed enzymes can lead to vastly different evolutionary outcomes, resulting in new mechanistic solutions to complex chemical transformations.

Improved survival over time with immunotherapy in locally advanced and metastatic cutaneous squamous cell carcinomas.

PURPOSE: Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer in white-skinned populations. There is little information on the epidemiology of cSCC, and even less on advanced cases (acSCC). Therefore, we analyzed acSCC patients to describe their characteristics, management, and outcomes over time. METHODS: A single-center retrospective study was conducted over a period of 5 years, including all patients who started systemic therapy for acSCC. The patient characteristics, cSCC management, response to therapy, and survival were recorded. Patients were stratified into equal chronological periods (periods 1 and 2). A subgroup analysis was performed to compare patients who received immunotherapy (group 1) with those who did not (group 2). RESULTS: The study included 127 patients, and patient numbers increased by an average of 19.7% per year. Most patients were male (88/127), elderly (mean 81.6 years), with comorbidities, and 27.6% were immunocompromised. The median overall survival (OS) was higher in period 2 (20 months) than in period 1 (10 months) (hazard ratio [95% confidence interval] = 0.62 [0.39; 0.98], p = 0.04). The risk of progression increased with age and immunosuppression. Of the 64 patients who received second-line therapy, 38 had immunotherapy (group 1) and 26 received other therapies (group 2). Immunotherapy reduced mortality and progression by 71% (p = 0.004) and 67% (p = 0.002), respectively. CONCLUSIONS: Patients with acSCC are usually very frail and elderly. OS increased over time, with a twofold improvement between periods 1 and 2, whereas progression-free survival (PFS) did not increase. Access to immunotherapy reduced mortality in a majority of patients in period 2. Immunosuppression and advanced age were associated with lower PFS.

Clinical impact of proton pump inhibitors and other co-medications on advanced melanoma patients treated with BRAF/MEK inhibitors.

PURPOSE: While several studies reported the influence of co-medications on immune checkpoint therapy and chemotherapy, it remains poorly studied with targeted therapy. Targeted therapies inhibiting BRAF and MEK had significantly improved management of advanced melanoma with BRAFV600 mutation over the last decade, we aimed to investigate the possible influence of co-mediations on the efficacy and toxicity of these targeted therapies (TT). METHODS: We conducted an observational study identifying patients with advanced melanoma treated with BRAF/MEK inhibitors between 2013 and 2020 in the Bordeaux University Hospital. Co-medications given within 1 month before until 3 months after the initiation of targeted therapy were recorded and classified by their mechanism or by their metabolism. Survival data were analyzed with univariable and multivariable cox regression and the combined effect of multiple factors was evaluated using a factor analysis of mixed data (FAMD). The impact of co-medications on toxicity related to TT was also assessed. RESULTS: A total of 192 patients were included. Although several co-medications were associated with significantly shorter overall survival (OS) and/or progression-free survival (PFS), PPIs was the only co-medication with a significant impact in multivariable analysis considering all co-medications and specific prognostic factors. Co-medications did not influence the risk, type, or timing of TT-related toxicity. Additional FAMD revealed the impact of each factor on the oncological outcomes. In a subgroup of patients, residual plasma TT concentration was available and did not differ between PPIs users and non-users. CONCLUSION: Co-medications, especially PPIs, must be carefully assessed at the time of TT initiation.

Immune checkpoint inhibitor rechallenge in patients who previously experienced immune-related inflammatory arthritis: a multicentre observational study.

OBJECTIVE: Another course of immune checkpoint inhibitors (ICIs) is often considered in patients with cancer progression and previous immune-related adverse events, including inflammatory arthritis (ICI-IA), but there are limited data regarding safety of ICI rechallenge in this setting. We aimed to assess the rate and clinical features associated with ICI-IA flare/recurrence on ICI rechallenge. METHODS: We conducted a multicentre observational study including cancer patients with ICI-IA who started a second course of ICI more than 3 months after ICI discontinuation in four French university hospitals. Primary outcome was the frequency of ICI flare/recurrence after ICI rechallenge. RESULTS: Twenty-three patients were included. At the time of ICI rechallenge, 18 patients reported no symptoms of ICI-IA (78%) and 5 had grade 1 (22%), 11 patients (48%) were not receiving any ICI-IA treatment, 11 (48%) were still on prednisone, 2 (9%) were on conventional synthetic disease-modifying antirheumatic drugs and 1 (4%) on anti-IL-6. ICI-IA flare/recurrence occurred in 12 patients (52%) with a median time of 1 month after ICI rechallenge. ICI-IA phenotype, disease activity and ICI-IA treatment at the time of ICI rechallenge did not differ according to ICI-IA flare/recurrence status. CONCLUSION: In this first observational study of ICI-IA patients rechallenged with ICI, about half of the patients experienced ICI-IA flare/recurrence with a similar phenotype but occurring earlier than the initial ICI-IA, warranting close monitoring during the first month of retreatment. Risk of flare did not differ according to baseline immunosuppressive treatment at the time of rechallenge.

Efficacy of Immune Checkpoint Inhibitor (ICI) Rechallenge in Advanced Melanoma Patients' Responders to a First Course of ICI: A Multicenter National Retrospective Study of the French Group of Skin Cancers (Groupe de Cancérologie Cutanée, GCC).

BACKGROUND: The long-term effectiveness of immune checkpoint inhibitor (ICI) rechallenge for progressive or recurrent advanced melanoma following previous disease control induced by ICI has not been thoroughly described in the literature. PATIENTS AND METHODS: In this retrospective multicenter national real-life study, we enrolled patients who had been rechallenged with an ICI after achieving disease control with a first course of ICI, which was subsequently interrupted. The primary objective was to evaluate tumor response, while the secondary objectives included assessing the safety profile, identifying factors associated with tumor response, and evaluating survival outcomes. RESULTS: A total of 85 patients from 12 centers were included in the study. These patients had advanced (unresectable stage III or stage IV) melanoma that had been previously treated and controlled with a first course of ICI before undergoing rechallenge with ICI. The rechallenge treatments consisted of pembrolizumab (n = 44, 52%), nivolumab (n = 35, 41%), ipilimumab (n = 2, 2%), or ipilimumab plus nivolumab (n = 4, 5%). The best overall response rate was 54%. The best response was a complete response in 30 patients (35%), a partial response in 16 patients (19%), stable disease in 18 patients (21%) and progressive disease in 21 patients (25%). Twenty-eight adverse events (AEs) were reported in 23 patients (27%), including 18 grade 1-2 AEs in 14 patients (16%) and 10 grade 3-4 AEs in nine patients (11%). The median progression-free survival (PFS) was 21 months, and the median overall survival (OS) was not reached at the time of analysis. Patients who received another systemic treatment (chemotherapy, targeted therapy or clinical trial) between the two courses of ICI had a lower response to rechallenge (p = 0.035) and shorter PFS (p = 0.016). CONCLUSION: Rechallenging advanced melanoma patients with ICI after previous disease control induced by these inhibitors resulted in high response rates (54%) and disease control (75%). Therefore, ICI rechallenge should be considered as a relevant therapeutic option.