A phase 1 study of triple-targeted therapy with BRAF, MEK, and AKT inhibitors for patients with BRAF-mutated cancers.

BACKGROUND: Aberrant PI3K/AKT signaling in BRAF-mutant cancers contributes to resistance to BRAF inhibitors. The authors examined dual MAPK and PI3K pathway inhibition in patients who had BRAF-mutated solid tumors (ClinicalTrials.gov identifier NCT01902173). METHODS: Patients with BRAF V600E/V600K-mutant solid tumors received oral dabrafenib at 150 mg twice daily with dose escalation of oral uprosertib starting at 50 mg daily, or, in the triplet cohorts, with dose escalation of both oral trametinib starting at 1.5 mg daily and oral uprosertib starting at 25 mg daily. Dose-limiting toxicities (DLTs) were assessed within the first 56 days of treatment. Radiographic responses were assessed at 8-week intervals. RESULTS: Twenty-seven patients (22 evaluable) were enrolled in parallel doublet and triplet cohorts. No DLTs were observed in the doublet cohorts (N = 7). One patient had a DLT at the maximum administered dose of triplet therapy (dabrafenib 150 mg twice daily and trametinib 2 mg daily plus uprosertib 75 mg daily). Three patients in the doublet cohorts had partial responses (including one who had BRAF inhibitor-resistant melanoma). Two patients in the triplet cohorts had a partial response, and one patient had an unconfirmed partial response. Pharmacokinetic data suggested reduced dabrafenib and dabrafenib metabolite exposure in patients who were also exposed to both trametinib and uprosertib, but not in whose who were exposed to uprosertib without trametinib. CONCLUSIONS: Concomitant inhibition of both the MAPK and PI3K-AKT pathways for the treatment of BRAF-mutated cancers was well tolerated, leading to objective responses, but higher level drug-drug interactions affected exposure to dabrafenib and its metabolites.

Out-of-Sequence Signal 3 Paralyzes Primary CD4(+) T-Cell-Dependent Immunity.

Primary T cell activation involves the integration of three distinct signals delivered in sequence: (1) antigen recognition, (2) costimulation, and (3) cytokine-mediated differentiation and expansion. Strong immunostimulatory events such as immunotherapy or infection induce profound cytokine release causing "bystander" T cell activation, thereby increasing the potential for autoreactivity and need for control. We show that during strong stimulation, a profound suppression of primary CD4(+) T-cell-mediated immune responses ensued and was observed across preclinical models and patients undergoing high-dose interleukin-2 (IL-2) therapy. This suppression targeted naive CD4(+) but not CD8(+) T cells and was mediated through transient suppressor of cytokine signaling-3 (SOCS3) inhibition of the STAT5b transcription factor signaling pathway. These events resulted in complete paralysis of primary CD4(+) T cell activation, affecting memory generation and induction of autoimmunity as well as impaired viral clearance. These data highlight the critical regulation of naive CD4(+) T cells during inflammatory conditions.

Patient-reported tolerability of adjuvant ipilimumab (3 or 10 mg/kg) versus high-dose interferon alfa-2b for resected high-risk stage III-IV melanoma in phase III trial E1609.

PURPOSE: Trial E1609 demonstrated superior overall survival with ipilimumab 3 mg/kg (ipi3) compared to high-dose interferon (HDI) for patients with resected high-risk melanoma. To inform treatment tolerability, we compared health-related quality of life (HRQoL), gastrointestinal (GI), and treatment-specific physical and cognitive/emotional symptoms. We also compared treatment-specific concerns between all arms. METHODS: We assessed HRQoL using the Functional Assessment of Cancer Therapy-General, physical and cognitive/emotional concerns using the FACT-Biologic Response Modifier subscale, and GI symptoms with the Functional Assessment of Chronic Illness Therapy-Diarrhea subscale pre-treatment and every 3 months. The primary outcome was the difference in HRQoL at 3 months between ipi3/ipi10 vs. HDI. RESULTS: 549 patients (n = 158 ipi3; n = 191 ipi10; n = 200 HDI) were analyzed. 3-month completion was 58.7%. Compared to HDI, ipilimumab patients reported better HRQoL (ipi3 = 87.5 ± 14.6 vs. HDI = 74.7 ± 15.4, p < .001; ipi10 = 84.9 ± 16.5 vs. HDI, p < .001) and fewer physical (ipi3 = 22.3 ± 4.6 vs. HDI = 17.1 ± 5.4, p < .001; ipi10 = 21.8 ± 5.0 vs. HDI p < .001) and cognitive/emotional (ipi3 = 18.6 ± 4.4 vs. HDI = 15.0 ± 5.3, p < .001; ipi10 = 17.7 ± 4.8 vs. HDI p < .001) concerns, but worse GI symptoms (ipi3 = 40.8 ± 5.0 vs. HDI = 42.2 ± 2.9, p = .011; ipi10 = 39.5 ± 7.0 vs. HDI, p < .001). Fewer ipilimumab patients reported worsening treatment-specific concerns (e.g., 52% of ipi3 and 58% of ipi10 reported worsening fatigue vs. 82% HDI, p's < .001). CONCLUSION: PROs demonstrated less toxicity of ipi3 compared to HDI and ipi10. Priorities for symptom management among patients receiving ipilimumab include GI toxicities, fatigue, weakness, appetite loss, arthralgia, and depression. TRIAL REGISTRATION: NCT01274338, January 11, 2011 (first posted date) https://clinicaltrials.gov/ct2/show/NCT01274338?term=NCT01274338&draw=2&rank=1 .

Science gone translational: the OX40 agonist story.

OX40 (CD134) is a tumor necrosis factor (TNF) receptor expressed primarily on activated CD4(+) and CD8(+) T cells and transmits a potent costimulatory signal when engaged. OX40 is transiently expressed after T-cell receptor engagement and is upregulated on the most recently antigen-activated T cells within inflammatory lesions (e.g. sites of autoimmune destruction and on tumor-infiltrating lymphocytes). Hence, it is an attractive target to modulate immune responses: OX40 blocking agents to inhibit undesirable inflammation or OX40 agonists to enhance immune responses. In regards to this review, OX40 agonists enhance anti-tumor immunity, which leads to therapeutic effects in mouse tumor models. A team of laboratory and clinical scientists at the Providence Cancer Center has collaborated to bring the preclinical observations in cancer models from the bench to the bedside. This review describes the journey from in vitro experiments through preclinical mouse models to the successful translation of the first OX40 agonist to the clinic for the treatment of patients with cancer.

Defining a functionally distinct subset of human memory CD4+ T cells that are CD25POS and FOXP3NEG.

Surface expression of the IL-2 receptor α-chain (CD25) has been used to discriminate between CD4(+) CD25(HI) FOXP3(+) regulatory T (Treg) cells and CD4(+) CD25(NEG) FOXP3(-) non-Treg cells. However, this study reports that the majority of resting human memory CD4(+) FOXP3(-) T cells expresses intermediate levels of CD25 and that CD25 expression can be used to delineate a functionally distinct memory subpopulation. The CD25(NEG) memory T-cell population contains the vast majority of late differentiated cells that respond to antigens associated with chronic immune responses and are increased in patients with systemic lupus erythematosus (SLE). In contrast, the CD25(INT) memory T cells respond to antigens associated with recall responses, produce a greater array of cytokines, and are less dependent on costimulation for effector responses due to their expression of CD25. Lastly, compared to the CD25(NEG) and Treg-cell populations, the CD25(INT) memory population is lost to a greater degree from the blood of cancer patients treated with IL-2. Collectively, these results show that in humans, a large proportion of CD4(+) memory T cells express intermediate levels of CD25, and this CD25(INT) FOXP3(-) subset is a functionally distinct memory population that is uniquely affected by IL-2.

Cancer's Dark Matter: Lighting the Abyss Unveils Universe of New Therapies.

The authors of a recent study identified noncanonical peptides (NCP) presented by cancer cells' HLA and observed lack of reactivity to these antigens by endogenous tumor-reactive T cells. In vitro sensitization generated NCP-reactive T cells that recognized epitopes shared by a majority of cancers tested, providing opportunities for novel therapies to shared antigens. See related article by Lozano-Rabella et al., p. 2250.

SALVO: Single-Arm Trial of Ipilimumab and Nivolumab as Adjuvant Therapy for Resected Mucosal Melanoma.

PURPOSE: Mucosal melanoma is a rare, aggressive form of melanoma with extremely high recurrence rates despite definitive surgical resection with curative intent. Currently there is no consensus on adjuvant therapy. Data on checkpoint inhibitors for adjuvant therapy are lacking. PATIENTS AND METHODS: We performed a single-arm, multicenter clinical trial using "flip dose" ipilimumab (1 mg/kg q3w × 4 cycles), and nivolumab (3 mg/kg q3w × 4 cycles), then nivolumab 480 mg q4w × 11 cycles to complete a year of adjuvant therapy. Participants must have had R0/R1 resection ≤90 days before registration, no prior systemic therapy (adjuvant radiotherapy allowed), ECOG 0/1, and no uncontrolled autoimmune disease or other invasive cancer. Patients were recruited through the Midwest Melanoma Partnership/Hoosier Oncology Network. RESULTS: From September 2017 to August 2021, 35 patients were enrolled. Of these, 29 (83%) had R0 resections, and 7 (20%) received adjuvant radiotherapy. Median age was 67 years, 21 (60.0%) female. Recurrence-free survival (RFS) rates at 1 and 2 years were 50% [95% confidence interval (CI), 31%-66%] and 37% (95% CI, 19%-55%), respectively. Overall survival rates at 1 and 2 years were 87% (95% CI, 68%-95%) and 68% (95% CI, 46%-83%), respectively. Median RFS was 10.3 months (95% CI, 5.7-25.8). Most common grade 3 toxicities were diarrhea (14%), hypertension (14%), and hyponatremia (11%), with no grade 4/5 toxicities. CONCLUSIONS: Flip-dose ipilimumab and nivolumab after resection of mucosal melanoma is associated with outcomes improved over that of surgical resection alone. Long-term follow-up, subgroup analyses and correlative studies are ongoing.

Bempegaldesleukin Plus Nivolumab in Untreated Advanced Melanoma: The Open-Label, Phase III PIVOT IO 001 Trial Results.

PURPOSE: Despite marked advances in the treatment of unresectable or metastatic melanoma, the need for novel therapies remains. Bempegaldesleukin (BEMPEG), a pegylated interleukin-2 (IL-2) cytokine prodrug, demonstrated efficacy in the phase II PIVOT-02 trial. PIVOT IO 001 (ClinicalTrials.gov identifier: NCT03635983) is a phase III, randomized, open-label study that builds on the PIVOT-02 results in first-line melanoma. METHODS: Patients with previously untreated, unresectable, or metastatic melanoma were randomly assigned 1:1 to receive BEMPEG plus nivolumab (NIVO) or NIVO monotherapy. Primary end points were objective response rate (ORR) and progression-free survival (PFS) by blinded independent central review and overall survival (OS). Secondary and exploratory end points included additional efficacy measures, safety, and pharmacokinetics (PKs) and pharmacodynamics analyses. RESULTS: In 783 patients (n = 391, BEMPEG plus NIVO; n = 392, NIVO monotherapy), the median follow-up was 11.6 months in the intent-to-treat population. The ORR with BEMPEG plus NIVO was 27.7% versus 36.0% with NIVO (two-sided P = .0311). The median PFS with BEMPEG plus NIVO was 4.17 months (95% CI, 3.52 to 5.55) versus 4.99 months (95% CI, 4.14 to 7.82) with NIVO (hazard ratio [HR], 1.09; 97% CI, 0.88 to 1.35; P = .3988). The median OS was 29.67 months (95% CI, 22.14 to not reached [NR]) with BEMPEG plus NIVO versus 28.88 months (95% CI, 21.32 to NR) with NIVO (HR, 0.94; 99.929% CI, 0.59 to 1.48; P = .6361). Grade 3-4 treatment-related adverse events (AEs) and serious AE rates were higher with the combination (21.7% and 10.1%, respectively) versus NIVO (11.5% and 5.5%, respectively). BEMPEG PK exposure and absolute lymphocyte count changes after BEMPEG plus NIVO were comparable between PIVOT IO 001 and PIVOT-02. CONCLUSION: The PIVOT IO 001 study did not meet its primary end points of ORR, PFS, and OS. Increased toxicity was observed with BEMPEG plus NIVO versus NIVO.

Phase 1 dose-escalation study of SEA-CD40: a non-fucosylated CD40 agonist, in advanced solid tumors and lymphomas.

BACKGROUND: SEA-CD40 is an investigational, non-fucosylated, humanized monoclonal IgG1 antibody that activates CD40, an immune-activating tumor necrosis factor receptor superfamily member. SEA-CD40 exhibits enhanced binding to activating FcγRIIIa, possibly enabling greater immune stimulation than other CD40 agonists. A first-in-human phase 1 trial was conducted to examine safety, pharmacokinetics, and pharmacodynamics of SEA-CD40 monotherapy in patients with advanced solid tumors and lymphoma. METHODS: SEA-CD40 was administered intravenously to patients with solid tumors or lymphoma in 21-day cycles with standard 3+3 dose escalation at 0.6, 3, 10, 30, 45, and 60 µg/kg. An intensified dosing regimen was also studied. The primary objectives of the study were to evaluate the safety and tolerability and identify the maximum tolerated dose of SEA-CD40. Secondary objectives included evaluation of the pharmacokinetic parameters, antitherapeutic antibodies, pharmacodynamic effects and biomarker response, and antitumor activity. RESULTS: A total of 67 patients received SEA-CD40 including 56 patients with solid tumors and 11 patients with lymphoma. A manageable safety profile was observed, with predominant adverse events of infusion/hypersensitivity reactions (IHRs) reported in 73% of patients. IHRs were primarily ≤grade 2 with an incidence associated with infusion rate. To mitigate IHRs, a standardized infusion approach was implemented with routine premedication and a slowed infusion rate. SEA-CD40 infusion resulted in potent immune activation, illustrated by dose dependent cytokine induction with associated activation and trafficking of innate and adaptive immune cells. Results suggested that doses of 10-30 µg/kg may result in optimal immune activation. SEA-CD40 monotherapy exhibited evidence of antitumor activity, with a partial response in a patient with basal cell carcinoma and a complete response in a patient with follicular lymphoma. CONCLUSIONS: SEA-CD40 was tolerable as monotherapy and induced potent dose dependent immune cell activation and trafficking consistent with immune activation. Evidence of monotherapy antitumor activity was observed in patients with solid tumors and lymphoma. Further evaluation of SEA-CD40 is warranted, potentially as a component of a combination regimen. TRIAL REGISTRATION NUMBER: NCT02376699.

Phase 1, open-label, dose-escalation study on the safety, pharmacokinetics, and preliminary efficacy of intravenous Coxsackievirus A21 (V937), with or without pembrolizumab, in patients with advanced solid tumors.

BACKGROUND: Oncolytic virus V937 showed activity and safety with intratumoral administration. This phase 1 study evaluated intravenous V937±pembrolizumab in patients with advanced solid tumors. METHODS: Patients had advanced non-small cell lung cancer (NSCLC), urothelial cancer, metastatic castration-resistant prostate cancer, or melanoma in part A (V937 monotherapy), and metastatic NSCLC or urothelial cancer in part B (V937+pembrolizumab). Prior immunotherapy was permitted >28 days before study treatment. Patients received intravenous V937 on days 1, 3, and 5 (also on day 8 in part B) of the first 21-day cycle and on day 1 of subsequent cycles for eight cycles. Three ascending dose-escalation cohorts were studied. Dose-escalation proceeded if no dose-limiting toxicities (DLTs) occurred in cycle 1 of the previous cohort. In part B, patients also received pembrolizumab 200 mg every 3 weeks from day 8 for 2 years; dose-expansion occurred at the highest-dose cohort. Serial biopsies were performed. RESULTS: No DLTs occurred in parts A (n=18) or B (n=85). Grade 3-5 treatment-related adverse events (AEs) were not observed in part A and were experienced by 10 (12%) patients in part B. The most frequent treatment-related AEs (any grade) in part B were fatigue (36%), pruritus (18%), myalgia (14%), diarrhea (13%), pyrexia (13%), influenza-like illness (12%), and nausea (12%). At the highest tested dose, median intratumoral V937 concentrations were 117,631 copies/mL on day 8, cycle 1 in part A (n=6) and below the detection limit for most patients (86% (19/22)) on day 15, cycle 1 in part B. Objective response rates were 6% (part A), 9% in the NSCLC dose-expansion cohort (n=43), and 20% in the urothelial cancer dose-expansion cohort (n=35). CONCLUSIONS: Intravenous V937+pembrolizumab had a manageable safety profile. Although V937 was detected in tumor tissue, in NSCLC and urothelial cancer, efficacy was not greater than that observed in previous studies with pembrolizumab monotherapy. TRIAL REGISTRATION NUMBER: NCT02043665.

Combination Dabrafenib and Trametinib Versus Combination Nivolumab and Ipilimumab for Patients With Advanced BRAF-Mutant Melanoma: The DREAMseq Trial-ECOG-ACRIN EA6134.

PURPOSE: Combination programmed cell death protein 1/cytotoxic T-cell lymphocyte-4-blockade and dual BRAF/MEK inhibition have each shown significant clinical benefit in patients with BRAFV600-mutant metastatic melanoma, leading to broad regulatory approval. Little prospective data exist to guide the choice of either initial therapy or treatment sequence in this population. This study was conducted to determine which initial treatment or treatment sequence produced the best efficacy. PATIENTS AND METHODS: In a phase III trial, patients with treatment-naive BRAFV600-mutant metastatic melanoma were randomly assigned to receive either combination nivolumab/ipilimumab (arm A) or dabrafenib/trametinib (arm B) in step 1, and at disease progression were enrolled in step 2 to receive the alternate therapy, dabrafenib/trametinib (arm C) or nivolumab/ipilimumab (arm D). The primary end point was 2-year overall survival (OS). Secondary end points were 3-year OS, objective response rate, response duration, progression-free survival, crossover feasibility, and safety. RESULTS: A total of 265 patients were enrolled, with 73 going onto step 2 (27 in arm C and 46 in arm D). The study was stopped early by the independent Data Safety Monitoring Committee because of a clinically significant end point being achieved. The 2-year OS for those starting on arm A was 71.8% (95% CI, 62.5 to 79.1) and arm B 51.5% (95% CI, 41.7 to 60.4; log-rank P = .010). Step 1 progression-free survival favored arm A (P = .054). Objective response rates were arm A: 46.0%; arm B: 43.0%; arm C: 47.8%; and arm D: 29.6%. Median duration of response was not reached for arm A and 12.7 months for arm B (P < .001). Crossover occurred in 52% of patients with documented disease progression. Grade ≥ 3 toxicities occurred with similar frequency between arms, and regimen toxicity profiles were as anticipated. CONCLUSION: Combination nivolumab/ipilimumab followed by BRAF and MEK inhibitor therapy, if necessary, should be the preferred treatment sequence for a large majority of patients.

Integrating new therapies in the treatment of advanced melanoma.

Treatments for advanced melanoma have evolved rapidly based on improved understanding of the pathways that determine T-cell responses and knowledge of growth-related mutations, which can be targeted with new classes of pharmacologic agents. The FDA approved ipilimumab and vemurafenib for advanced melanoma in 2011. Our practice is to evaluate all tumors from patients with metastatic disease for the presence of a BRAF mutation (Fig. 1). More than 20 years of follow-up show that responders to IL-2 can be cured of their melanoma. Therefore, we recommend high-dose IL-2 as first line therapy for patients with excellent functional status and normal cardiopulmonary reserve regardless of their BRAF mutation status. We use ipilimumab, which can induce durable tumor regressions and improved survival, as initial therapy for patients who refuse or are not candidates for IL-2, also regardless of their BRAF mutation status. Ipilimumab can be used as salvage therapy for patients with advanced disease after IL-2 or vemurafenib. Targeted therapies such as vemurafenib or imatinib can be offered to patients whose melanomas express the BRAF V600E or C-Kit mutations. Vemurafenib is particularly useful for patients whose disease is progressing rapidly, as clinical improvement can be obtained within days of starting therapy and response rates may be as high as 70 %. The major reason we do not recommend vemurafenib as first line treatment in all patients whose tumors have BRAF mutations is the short median duration of response of approximately 7 months. Enrollment in a clinical trial should always be considered for patients with metastatic melanoma. The clinical trial focus has changed from finding any agent with activity in melanoma, to overcoming mechanisms of resistance and enhancing the immunomodulatory activity of these new agents that confer therapeutic benefit. Selected patients can benefit from surgical resection or radiation to manage oligometastatic disease.

A Phase II, Single-arm Trial of Sunitinib and Erlotinib in Advanced Renal Cell Carcinoma.

BACKGROUND: Overexpression of the epidermal growth factor receptor (EGFR) and its ligands occur frequently in renal cell carcinoma (RCC). Combined vascular endothelial growth factor receptor (VEGF-R) and EGFR inhibition may overcome resistance to VEGF-R inhibitor monotherapy. We performed a dose-escalation phase II study of sunitinib plus erlotinib in advanced renal cell carcinoma. PATIENTS AND METHODS: Patients with metastatic clear cell or papillary RCC were eligible. Prior therapy was allowed except sunitinib or erlotinib. Three dose levels of erlotinib (50, 100, 150 mg daily) were evaluated in combination with sunitinib 50 mg. Thirty-seven patients were treated at maximum tolerated dose to determine efficacy. The primary endpoint was 8-month progression-free survival (PFS) rate. The trial was powered to assess for a difference between a median PFS of less than 50% with a targeted 70% PFS for the combination. RESULTS: The 8-month PFS rate was 40% (95% CI: 23-56). Median PFS was 5.8 months (95% CI: 4.1-9.7) and median overall survival (OS) was 26.3 months (95% CI: 16.1-34.0). The objective response rate was 22% and an additional 59% of patients had stable disease for at least 6 weeks. The most common adverse events for all grades were diarrhea, rash, fatigue, and dysgeusia. Dose reduction in 1 or both of the drugs was undertaken in 17 (46%) patients, while 5 (14%) discontinued study therapy due to toxicity. CONCLUSION: While sunitinib and erlotinib are combinable,the 8-month PFS rate did not suggest efficacy improvement over sunitinib monotherapy (NCT00425386).

Intratumoral oncolytic virus V937 plus ipilimumab in patients with advanced melanoma: the phase 1b MITCI study.

BACKGROUND: Intratumoral administration of V937, a bioselected, genetically unmodified coxsackievirus A21, has previously demonstrated antitumor activity in patients with advanced melanoma as monotherapy and in combination with the programmed cell death 1 (PD-1) antibody pembrolizumab. We report results from an open-label, single-arm, phase 1b study (NCT02307149) evaluating V937 plus the cytotoxic T-lymphocyte antigen 4 inhibitor ipilimumab in patients with advanced melanoma. METHODS: Adult patients (aged ≥18 years) with histologically confirmed metastatic or unresectable stage IIIB/C or IV melanoma received intratumoral V937 on days 1, 3, 5, 8, and 22 and every 3 weeks (Q3W) thereafter for up to 19 sets of injections plus intravenous ipilimumab 3 mg/kg Q3W administered for four doses starting on day 22. Imaging was performed at screening, on days 43 and 106 and every 6 weeks thereafter; response was assessed by immune-related response criteria per investigator assessment. Primary endpoints were safety in all treated patients and objective response rate (ORR) in all treated patients and in patients with disease that progressed on prior anti-PD-1 therapy. RESULTS: Fifty patients were enrolled and treated. ORR was 30% (95% CI 18% to 45%) among all treated patients, 47% (95% CI 23% to 72%) among patients who had not received prior anti-PD-1 therapy, and 21% (95% CI 9% to 39%) among patients who had experienced disease progression on prior anti-PD-1 therapy. Tumor regression occurred in injected and non-injected lesions. Median immune-related progression-free survival was 6.2 months (95% CI 3.5 to 9.0 months), and median overall survival was 45.1 months (95% CI 28.3 months to not reached). The most common treatment-related adverse events (AEs) were pruritus (n=25, 50%), fatigue (n=22, 44%), and diarrhea (n=16, 32%). There were no V937-related dose-limiting toxicities and no treatment-related grade 5 AEs. Treatment-related grade 3 or 4 AEs, all of which were considered related to ipilimumab, occurred in 14% of patients (most commonly dehydration, diarrhea, and hepatotoxicity in 4% each). CONCLUSIONS: Responses associated with intratumoral V937 plus ipilimumab were robust, including in the subgroup of patients who had experienced disease progression on prior anti-PD-1 therapy. Toxicities were manageable and consistent with those of the individual monotherapies.

Trough levels of ipilimumab in serum as a potential biomarker of clinical outcomes for patients with advanced melanoma after treatment with ipilimumab.

BACKGROUND: Immune checkpoint blockade (ICB) using anti-CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of advanced cancer. However, ICB is effective for only a small fraction of patients, and biomarkers such as expression of PD-L1 in tumor or serum levels of CXCL11 have suboptimal sensitivity and specificity. Exposure-response (E-R) relationships have been observed with other therapeutic monoclonal antibodies. There are many factors influencing E-R relationships, yet several studies have shown that trough levels of anti-PD-1/PD-L1 correlated with clinical outcomes. However, the potential utility of anti-CTLA-4 levels as a biomarker remains unknown. METHODS: Serum was obtained at trough levels at weeks 7 and 12 (after doses 2 and 4) from patients with advanced melanoma who received ipilimumab alone (3 mg/kg every 3 weeks for four treatments) via an expanded access program (NCT00495066). We have successfully established a proteomics assay to measure the concentration of ipilimumab in serum using an liquid chromatography with tandem mass spectrometry-based nanosurface and molecular-orientation limited proteolysis (nSMOL) approach. Serum samples from 38 patients were assessed for trough levels of ipilimumab by the nSMOL assay. RESULTS: We found that trough levels of ipilimumab were higher in patients who developed immune-related adverse events but did not differ based on the presence or absence of disease progression. We found that patients with higher trough levels of ipilimumab had better overall survival when grouped based on ipilimumab trough levels. Trough levels of ipilimumab were inversely associated with pretreatment serum levels of CXCL11, a predictive biomarker we previously identified, and soluble CD25 (sCD25), a prognostic biomarker for advanced melanoma, as well as C reactive protein (CRP) and interleukin (IL)-6 levels at week 7. CONCLUSIONS: Our results suggest that trough levels of ipilimumab may be a useful biomarker for the long-term survival of patients with advanced melanoma treated with ipilimumab. The association of ipilimumab trough levels with pretreatment serum levels of CXCL11 and sCD25 is suggestive of a baseline-driven E-R relationship, and the association of ipilimumab trough levels with on-treatment levels of CRP and IL-6 is suggestive of response-driven E-R relationship. Our findings highlight the potential utility of trough levels of ipilimumab as a biomarker. TRIAL REGISTRATION NUMBER: NCT00495066.

Neoadjuvant anti-OX40 (MEDI6469) therapy in patients with head and neck squamous cell carcinoma activates and expands antigen-specific tumor-infiltrating T cells.

Despite the success of checkpoint blockade in some cancer patients, there is an unmet need to improve outcomes. Targeting alternative pathways, such as costimulatory molecules (e.g. OX40, GITR, and 4-1BB), can enhance T cell immunity in tumor-bearing hosts. Here we describe the results from a phase Ib clinical trial (NCT02274155) in which 17 patients with locally advanced head and neck squamous cell carcinoma (HNSCC) received a murine anti-human OX40 agonist antibody (MEDI6469) prior to definitive surgical resection. The primary endpoint was to determine safety and feasibility of the anti-OX40 neoadjuvant treatment. The secondary objective was to assess the effect of anti-OX40 on lymphocyte subsets in the tumor and blood. Neoadjuvant anti-OX40 was well tolerated and did not delay surgery, thus meeting the primary endpoint. Peripheral blood phenotyping data show increases in CD4+ and CD8+ T cell proliferation two weeks after anti-OX40 administration. Comparison of tumor biopsies before and after treatment reveals an increase of activated, conventional CD4+ tumor-infiltrating lymphocytes (TIL) in most patients and higher clonality by TCRß sequencing. Analyses of CD8+ TIL show increases in tumor-antigen reactive, proliferating CD103+ CD39+ cells in 25% of patients with evaluable tumor tissue (N = 4/16), all of whom remain disease-free. These data provide evidence that anti-OX40 prior to surgery is safe and can increase activation and proliferation of CD4+ and CD8+ T cells in blood and tumor. Our work suggests that increases in the tumor-reactive CD103+ CD39+ CD8+ TIL could serve as a potential biomarker of anti-OX40 clinical activity.

HDAC inhibition prevents transgene expression downregulation and loss-of-function in T-cell-receptor-transduced T cells.

T cells that are gene-modified with tumor-specific T cell receptors are a promising treatment for metastatic melanoma patients. In a clinical trial, we treated seven metastatic melanoma patients with autologous T cells transduced to express a tyrosinase-reactive T cell receptor (TCR) (TIL 1383I) and a truncated CD34 molecule as a selection marker. We followed transgene expression in the TCR-transduced T cells after infusion and observed that both lentiviral- and retroviral-transduced T cells lost transgene expression over time, so that by 4 weeks post-transfer, few T cells expressed either lentiviral or retroviral transgenes. Transgene expression was reactivated by stimulation with anti-CD3/anti-CD28 beads and cytokines. TCR-transduced T cell lentiviral and retroviral transgene expression was also downregulated in vitro when T cells were cultured without cytokines. Transduced T cells cultured with interleukin (IL)-15 maintained transgene expression. Culturing gene-modified T cells in the presence of histone deacetylase (HDAC) inhibitors maintained transgene expression and functional TCR-transduced T cell responses to tumor. These results implicate epigenetic processes in the loss of transgene expression in lentiviral- and retroviral-transduced T cells.