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.

BXQ-350 may alleviate symptoms of chemotherapy- induced peripheral neuropathy via modulation of S1P

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Background: Chemotherapy Induced Peripheral Neuropathy (CIPN) is a debilitating side effect associated with many chemotherapeutic agents. It significantly impacts quality of life during treatment, causes lasting neuropathy, and may also shorten the treatment regimen, potentially impacting clinical benefit. The pathology of CIPN is still not completely understood, however, increasing evidence suggests sphingosine-1-phosphate (S1P) may be an important signaling molecule. Altered neuronal sphingolipid metabolism has been linked to neuropathic pain, evidenced by elevated plasma levels of S1P in patients receiving chemotherapy. Methods: BXQ-350 is a nanovesicle of Saposin C, an allosteric activator of sphingolipid metabolism, that lowers systemic S1P. BXQ-350 was investigated in an adult Phase 1 dose-escalation safety study in heavily pretreated all-comer cancer patients with advanced solid malignancies ( NCT02859857 ). The primary objective was to determine the safety profile and potential clinical activity of BXQ-350 as monotherapy. Samples were collected to explore potential biomarkers. Results: BXQ-350 was safe and well tolerated. Clinical signs of activity were observed in 13 patients (~17.8% of evaluable patients) experiencing a clinical benefit (PR, SD) up to cycle 6 and beyond including: 4 CRC, 1 pancreatic, and 1 GIST patient. Two patients are still on study six years after enrollment, including 1 CRC. Interestingly, a pancreatic cancer patient with chronic CIPN at time of enrollment spontaneously reported a significant improvement of her neuropathic symptoms shortly after receiving BXQ-350. Investigation of potential improvements in patients with chronic CIPN at time of enrollment revealed that 4 out of 10 patients experienced an improvement of their symptoms that seemed to be associated with a decrease in S1P systemic levels following BXQ-350 administration. BXQ-350 was subsequently investigated in a murine oxaliplatin-CIPN preclinical model with results showing a dose-dependent prevention/resolution of CIPN correlating with decreasing systemic S1P levels. Conclusions: Results of this Phase 1 study in heavily pretreated patients shows that BXQ-350 was well tolerated and seems to generate a clinical benefit via modulation of S1P. There were preliminary signs that BXQ-350 may alleviate symptoms of CIPN in relation to decreasing S1P concentration. Additional studies are underway to better understand this novel mechanism of action. Clinical trial information: 02859857 .

BXQ-350: Modulating ceramide and sphingosine-1-phosphate for antitumor activity in patients with advanced CRC

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Background: Sphingolipids are a class of bioactive signaling molecules implicated in multiple cellular processes and molecular pathways. Many publications have demonstrated that ceramides are proapoptotic, synergize with cancer treatments, and mitigate chemoresistance. Findings also demonstrated that sphingosine-1-phosphate (S1P) is a key sphingolipid that promotes cancer cell proliferation, activates multiple oncogenic pathways, and stimulates immuno-suppressor cell populations promoting a pro-tumoral microenvironment. Several studies of colorectal cancer patients have shown high levels of ceramides being associated with improved survival, while high S1P levels are associated with a poor prognosis. Hence, modulation of sphingolipid metabolism continues to be a promising treatment approach. Methods: BXQ-350 is a nanovesicle of Saposin C, an allosteric activator of sphingolipid metabolism, that lowers systemic S1P and increases C18 ceramide. BXQ-350 was investigated in a Phase 1 dose-escalation safety study in an all-comer cancer patients with advanced solid malignancies ( NCT02859857 ) to determine its safety profile and potential clinical activity as monotherapy. Samples were collected to explore potential biomarkers. Results: 13 patients (~17.8% of evaluable patients) had a clinical benefit up to cycle 6 (PR, SD), with the majority experiencing a decrease in systemic S1P levels and an increase in C18 levels. 8 patients (~11% of evaluable patients) had PFS > 6 months, with 2 patients still on study six years after enrollment. Analysis of plasma samples also revealed an increase in anti-tumoral cytokines (IFNg, TNFa, IL-2) and a decrease in pro-tumoral ones (IL-6, 8, 10). Among patients with PFS > 6 months, there were 4 recurrent CRC patients (1PR, 3SD): 1 patient had a PFS of ~12 months, 2 of ~18 months, and 1 is still on study after 6 years. Conclusions: Results of this Phase 1 study in heavily pretreated patients show BXQ-350 was well tolerated and seem to generate a clinical benefit in CRC patients via modulation of S1P and ceramides. A phase 2 trial of BXQ-350 in combination with FOLFOX/Bevacizumab in newly diagnosed mCRC is on-going with plans to further investigate this novel mechanism of action. Clinical trial information: 02859857 .

Abstract CT035: Safety, preliminary efficacy and pharmacodynamic (PD) analysis of maveropepimut-S, intermittent low-dose cyclophosphamide and pembrolizumab in patients with advanced, metastatic bladder cancer

Background: Maveropepimut-S (MVP-S) is a novel immunotherapeutic that educates a specific CD8 T cell response to the cancer antigen, survivin, to orchestrate immune-mediated elimination of survivin-expressing cancer cells. Specifically, MVP-S is a lipid-in-oil formulation of the DPX delivery platform, incorporating five survivin-specific immunogenic peptides, the innate immune stimulant, polydIdC, and a CD4 T cell helper peptide. In prior clinical studies, MVP-S and intermittent low-dose cyclophosphamide (CPA) elicited confirmed clinical responses (both partial and complete by RECISTv1.1) and induced a robust, durable survivin-specific CD8 T cell response. Moreover, the combination with pembrolizumab appeared to be well tolerated in solid tumors and lymphomas. The purpose of this phase 2 study is to explore whether this combination may be safe and effective in advanced, metastatic bladder cancer patients, both naïve to, and previously treated with, immune checkpoint inhibitors.

Results: Seventeen (17) subjects were treated with the combination of MVP-S, CPA and pembrolizumab. Subjects received an average of 3 prior lines of therapy with 13/17 (76.4%) having previously received an anti-PD1/L1. Seven subjects progressed on or after anti-PD1/L1 as last line of therapy prior to entering the trial. The combination was well-tolerated, with majority of AEs being grade 1 or grade 2. Five (5) out of 17 subjects showed response: 3 subjects with PR (unconfirmed) and 2 with CR (confirmed). Three of these, including the 2 CRs, had progressed on anti-PD-1/L1. Long-term clinical benefit has been observed in several subjects (one patient is still on treatment after 17 months) and coincides with an increase in detectable survivin-specific T cells in peripheral blood.

Conclusion: Preliminary data suggest that MVP-S/CPA and pembrolizumab is a well-tolerated combination and shows encouraging preliminary clinical activity in the treatment of advanced or metastatic bladder cancer patients, including patients who have progressed on prior anti-PD-1/L1 therapy.

Citation Format: Olivier Rixe, Vincent Castonguay, Henry Conter, Eva Chalas, Pratibha Desai, Christian Squillante, Lisa A. MacDonald, Rebekah Conlon, Yogesh Bramhecha, Heather Hirsch, Jeremy R. Graff, Stephan Fiset. Safety, preliminary efficacy and pharmacodynamic (PD) analysis of maveropepimut-S, intermittent low-dose cyclophosphamide and pembrolizumab in patients with advanced, metastatic bladder cancer [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 CT035.

Abstract 1975: Potential novel Immuno-oncology mechanism revealed during translational phase I Immuno-blood profiling of experimental ADC medicine OBT076 in a gastric cancer patient

CD205 is a type I transmembrane glycoprotein, with unique characteristics that make it an ideal target for Antibody Drug Conjugate (ADC) therapy. Here we report on a potential novel immuno-oncology mechanism revealed during the Translational Phase I (NCT04064359) immuno-blood profiling of a chemo-refractory patient treated with OBT076, an experimental CD205-directed ADC.

A chemo-refractory advanced gastric cancer patient with 60% CD205 expression in the primary tumor via IHC and having previously undergone 2 lines of chemotherapy treatment (Docetaxel/cisplatin/5FU and Ramucirumab/Paclitaxel), received five 21-day cycles of OBT076 (one at 2.5mg/kg and four cycles at 2.0 mg/kg) followed by 1 cycle of Pembrolizumab (PZ; 200mg) ~4 weeks later. Clinical response was evaluated and immunological markers (CD45, CD205, CD4, CD8, and PD1) in peripheral blood cells were quantified using flow cytometry.

After 2 OBT076 cycles at 2.0 mg/kg, there was an ~40% shrinkage in the primary gastric tumor size and resolution of ascites and lymph node metastases were observed. Following 2 further cycles and PZ, complete response was achieved for the primary tumor. Flow cytometry showed (1) an initial decrease in the absolute numbers of dendritic cells by day 8, followed by a 2-fold increase in numbers by day 21 after treatment; (2) a near total decrease in the population of CD8+ CD205+ cells by day 8, no recovery in levels were observed; (3) a 3-fold increase in CD4+ and CD8+ T-cell numbers between days 8 and 21 and (4) an initial decrease in CD4+ PD1+ and CD8+ PD1+ T-cell numbers followed by an ~4-fold increase between days 8 and 21.

In summary our results show that increases in PD1+ T-cells, T-cell induction, and decreases in immuno-suppressive CD4+ CD205+ and CD8+ CD205+ cells occur simultaneously; coinciding with rapid resolution of the primary tumor, lymph node metastases and ascites. These findings suggest that OBT076 activates the patient’s immune response against the tumor through a potentially novel mechanism: drug-induced depletion of CD8+ CD205+ immuno-suppressive cells and subsequent T-cell activation. Additionally, our data support the use of immune checkpoint inhibitors in conjunction with OBT076 to achieve favorable clinical outcomes.

Citation Format: Christian Rohlff, Solmaz Sahebjam, Alain Mita, Rosen Lee, Chander Sekhar Peddaboina, Arnima Bisht, Lindsey Hudson, Wolf Fridman, Abderrahim Fandi, Olivier Rixe. Potential novel Immuno-oncology mechanism revealed during translational phase I Immuno-blood profiling of experimental ADC medicine OBT076 in a gastric cancer patient [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 1975.

EPEN-14. A Phase 1, Safety and Dose Escalation Study of BXQ-350 in Patients with Advanced Solid Malignancies Demonstrates that BXQ-350 is Well Tolerated and Shows Signs of Potential Clinical Activity in Ependymoma Patients

The significance of a dysregulated sphingolipid metabolism in cancer, including brain tumors, has been demonstrated and several enzymes involved in sphingolipid metabolism are being investigated as novel therapeutic targets for adult and pediatric brain cancers. Saposin C (Sphingolipid Activator PrO[S]etIN) is a human protein encoded by the Psap gene and is an allosteric activator of several enzymes involved in sphingolipid/ceramide metabolism. BXQ-350 is a nanovesicle of Saposin C that has broad anticancer activity, selectively inducing apoptosis of cancer cells by lowering Sphingosine-1-Phosphate and increasing ceramides concentrations and inducing an anti-tumoral immune response. BXQ-350 was investigated in a Phase 1 dose-escalation safety study in cancer patients with advanced solid malignancies including brain tumors (NCT02859857). The primary objective of this single agent study was to describe the safety profile and to determine the maximum tolerated dose, or the biological effective dose, of BXQ-350 administered intravenously at escalating doses from 0.7 mg/kg up to 2.4 mg/kg. Multiple secondary parameters were included to characterize BXQ-350’s pharmacokinetic parameters, efficacy profile and potential biomarkers. This trial was performed at four US sites. Results indicate that BXQ-350 was safe and well-tolerated as no DLT was observed and an MTD was not reached. RANO or RECIST 1.1 criteria were used to evaluate tumor response. Analysis of plasma samples suggests that BXQ-350 modulates sphingolipid metabolism and impacts the immune system positively. Furthermore, potential signs of single agent activity were observed across tumor types, including in two ependymomas for which results will be presented.

A phase 1, safety and dose escalation study of BXQ-350, a nanovesicle formulation of saposin c, a modulator of sphingolipid metabolism, in patients with advanced solid malignancies

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Background: Bexion recently completed an all-comer Phase 1 clinical study of BXQ-350 in patients with advanced solid tumors including high grade gliomas to evaluate the safety profile and to determine the maximum tolerated- or biologically effective dose. BXQ-350 is a nanovesicle comprised of recombinantly expressed Saposin C (SapC) and dioleoylphosphatidylserine. SapC, a human protein encoded by the Psap gene, is an allosteric activator of several enzymes involved sphingolipid metabolism. Sphingolipids are bioactive signaling molecules implicated in multiple cellular processes including apoptosis and immune stimulation/inhibition. In nonclinical studies, BXQ-350 evidences broad anticancer activity, selectively inducing apoptosis of cancer cells by modulating sphingolipids (ceramides/S1P), and BXQ-350 acts synergistically with multiple classes of anticancer agents and treatments. Methods: In the trial (NTC02859857), performed at four US sites, BXQ-350 was administered intravenously for a minimum of 6 cycles over 28 weeks at escalating doses from 0.7 mg/kg up to 2.4 mg/kg. Multiple secondary parameters were included to characterize its pharmacokinetics, efficacy profile and identify potential biomarkers. Results: Results indicate that: i) BXQ-350 was safe and well-tolerated as no DLT was observed and an MTD was not reached; ii) treatment related adverse events leading to discontinuation were typical for this patient population and disease related; iii)* biomarker analyses suggest positive modulation of sphingolipid metabolism and stimulation of the immune system; iv)* surprisingly, some patients noted improvement of existing peripheral neuropathies. RANO or RECIST ver 1.1 criteria were used to evaluate tumor response: 13 patients reached Cycle 6 restaging (17% ORR); 8 patients (11.0% of evaluable patients) demonstrated progression free survival over more than 6 months; and 2 patients (a GBM and CRC patient) are still on study after 5 years. * subject of separate abstracts. Conclusions: In conclusion, BXQ-350 is a first-in-human and first-in-class novel biologic whose Phase 1 results suggest that it may have clinical utility either as a monotherapy or when combined with other targeted agents. Clinical trial information: 028559857.

Bedside to benchtop translational development: Targeting the S1P/ceramide axis may alleviate symptoms of chemical induced peripheral neuropathy

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Background: Chemical Induced Peripheral Neuropathy (CIPN) is a debilitating and serious side-effect associated with many chemotherapeutic treatments. Often, CIPN is a dose-limiting toxicity, and its effects can be long-lasting in some patients. The pathology of CIPN is thought to involve not only cytotoxicity of neuronal cells, but also inflammation and immune responses. Hence, it is not surprising that the sphingolipid sphingosine-1-phosphate (S1P) is thought to be a key contributor to CIPN. Methods: BXQ-350, a nanovesicle comprised of recombinantly expressed Saposin C and dioleoylphosphatidylserine, has broad anticancer activity. It modulates sphingolipid metabolism and signaling, lowers S1P and increases pro-apoptotic ceramides, and induces an anti-tumoral immune response. BXQ-350 was investigated in a Phase 1 dose-escalation safety study of all-comer cancer patients with advanced solid malignancies, including high grade gliomas ( NCT02859857 )*. Multiple secondary parameters were included to characterize BXQ-350’s pharmacokinetics, efficacy profile and to elucidate potential biomarkers. Results: Interestingly, several patients with established CIPN spontaneously reported improvement of their neuropathy-related symptoms following BXQ-350 administration. Plasma samples from those patients revealed changes in circulating levels of sphingolipids and cytokines, including reduction of circulating levels of S1P and of IL-6, IL-8, cytokines, following BXQ-350 dosing. These properties of BXQ-350 were subsequently investigated in a murine oxaliplatin-CIPN preclinical model; results showed a dose-dependent prevention/resolution of CIPN, which also correlated with decreasing systemic S1P levels. Additional plasma based CIPN specific biomarkers were investigated, and preclinical results suggest that BXQ-350 may also favorably inhibit specific immune cells that favor CPIN. Conclusions: These preclinical and clinical observations related to CIPN, coupled with the fact that BXQ-350 acts synergistically with many chemotherapies and radiation, warrant further its investigation into preventing or improving CIPN related symptoms in cancer patients. Clinical trial information: 02859857.

S1P/ceramides and cytokines as potential biomarkers of response following administration of bxq-350

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Background: BXQ-350 was investigated in a Phase 1 dose-escalation safety study of all-comer cancer patients with advanced solid malignancies, including high grade gliomas ( NCT02859857 ) (safety/efficacy results reported in a separate abstract). The primary objective of this single agent study was to describe the safety profile and to determine the maximum tolerated dose. Multiple secondary parameters were included to characterize BXQ-350’s pharmacokinetic parameters, efficacy profile and elucidation of potential biomarkers. BXQ-350 is a nanovesicle of recombinantly expressed Saposin C (SapC) and dioleoylphosphatidylserine. In nature, SapC is a protein encoded by the Psap gene, and serves as an allosteric activator of several enzymes involved in sphingolipid/ceramide metabolism, enzymes which are being investigated as novel therapeutic targets in cancers. Indeed, sphingolipids are a class of bioactive signaling molecules implicated in multiple cellular processes and molecular pathways. Amongst these sphingolipids, Sphingosine-1-Phosphate (S1P) induces cancer cell survival and proliferation, activates multiple oncogenic pathways, and promotes a pro-tumoral microenvironment. SapC has broad anticancer activity, lowering S1P and increasing ceramides, also inducing an anti-tumoral immune response. Methods: Lipodomic analysis (sphingolipids) and cytokines were analyzed in plasma samples of a subset of patients enrolled in this study. Results: Analysis of plasma biomarker samples, collected throughout the period patients were on study, reveals notable changes of circulating sphingolipids and cytokines. A subset of patients exhibited clinical benefits following BXQ-350 administration (see other presentation for details; ̃17% of the evaluable patients remained on study up to Cycle 6; and 8 patients (̃11%) with PFS> 6 months). Concomitant circulating changes in S1P and other ceramides may be indicative of treatment effect. Also, concurrent changes in circulating levels of pro/antitumoral cytokines were noted. Conclusions: While these results are exploratory and preliminary in nature, these initial results warrant further investigation. These observations will be further explored in specific cancer and non-cancer indications. Clinical trial information: 02859857.

Phase 1 study of OBT076, a first-in-class anti-DEC205 ADC, in patients with advanced/metastatic solid tumors: Safety, efficacy, and PK/PD results

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Background: OBT076, an Antibody Drug Conjugate (ADC) consisting of a fully human IgG1 antibody conjugated via a cleavable linker to the derivative microtubule inhibitor DM4. It has specificity for the CD205/Ly75 target antigen which is an endocytic receptor overexpressed on the cell surface and immunosuppressive dendritic cells. This phase 1 study evaluates safety, tolerability, PK/PD and preliminary efficacy of OBT076 in solid tumor patients with high expression of target protein CD205 (CAP-CLIA validated centralized IHC test). Methods: Open label, two parts trial in patients with metastatic CD205+ve solid tumors who progressed on standard therapy. Part 1 of the study consisted in dose escalation from 1.6 mg/kg to 3.5 mg/kg. An mTPI design is used to guide to determine the maximum tolerated dose (MTD) Treatment was given on day 1 every 3 weeks followed by GCSF on day 8. Blood samples and flow cytometry were used to assess PK/PD. Tumor response was assessed every three cycles. Part 2 of trial is an expansion basket trial enriched in indications where preliminary efficacy has been shown. Results: The study completed Part 1 dose escalation. Part 2 expansion phase is ongoing. Between Dec 2019 and January 2022, 20 patients were enrolled (18 patients in the dose escalation and 2 in the ongoing expansion). The median age 61, 9 patients were males and 9 had ECOG PS 0. All patients had at least one metastatic site and 90% received at least 2 lines of chemotherapy in the metastatic setting. Recommended dose for the expansion phase is 3.0 mg/kg. No other significant side effects have been observed. PK data showed that Cmax of 40.000-90.000 ng/ml was achieved between 2.5 and 3.5mg/kg dose and is comparable to the therapeutic dose in mouse models. In part 1 of the study, 7 patients derived clinical benefit despite being in disease progression at trial entry. One patient with gastric cancer with linitis plastica experienced major improvement with complete disappearance of ascites and metastatic adenopathy after cycle 3. The six other patients had lasting stable disease and received between 5-14+ cycles with median of 5 cycles. Two patients with low PD-L-1 expression received checkpoint inhibitor treatment with pembrolizumab after 2 and 5 cycles of OBT076, both patients experienced near complete response after only one to two cycles. Conclusions: OBT076 at 3.0mg/kg has shown favorable safety profile with manageable neutropenia. The preliminary efficacy has shown preliminary antitumoral single agent activity in gastric, ovarian and lung cancer. The two patients who received a sequential administration of pembrolizumab after OBT076 showed major tumor activity. Sequential administration of OBT076 followed by a PD-1 inhibitor was also supported by PD markers and warrants further evaluation. Clinical trial information: NCT04064359. [Table: see text]

Phase IB Study of GITR Agonist Antibody TRX518 Singly and in Combination with Gemcitabine, Pembrolizumab or Nivolumab in Patients with Advanced Solid Tumors

Purpose: TRX518 is a monoclonal antibody engaging the glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR). This open-label, phase I study (TRX518-003) evaluated the safety and efficacy of repeated dose TRX518 monotherapy and combination with gemcitabine, pembrolizumab or nivolumab in advanced solid tumors. Experimental Design: TRX518 monotherapy was dose-escalated (Part A) and expanded (Part B) up to 4 mg/kg load, 1 mg/kg Q3W. Parts C-E included dose-escalation (2mg/kg and 4 mg/kg loading followed by 1mg/kg) and dose-expansion (4mg/kg load) phases with gemcitabine (Part C), pembrolizumab (Part D) or nivolumab (Part E). Primary endpoints included incidence of dose-limiting toxicities (DLTs), serious adverse events (SAEs), and pharmacokinetics. Secondary endpoints were efficacy and pharmacodynamics. Results:109 patients received TRX518: 43 (Parts A+B), 30 (Part C), 26 (Part D), and 10 (Part E) respectively. 67% of patients in Parts D+E had received prior anti-PD(L)1 or anti-CTLA-4. No DLTs, treatment-related SAEs and/or G4/5 AEs were observed with TRX518 monotherapy. In Parts C-E, no DLTs were observed, although TRX518-related SAEs were reported in 3.3% (Part C) and 10.0% (Part E) respectively. Objective response rate was 3.2%, 3.8%, 4% and 12.5% in Parts A+B, C, D and E respectively. TRX518 affected peripheral and intratumoral regulatory T cells (Tregs) with different kinetics depending on the combination regimen. Responses with TRX518 monotherapy+anti-PD1 combination were associated with intratumoral Treg reductions and CD8 increases and activation after treatment. Conclusions:TRX518 showed an acceptable safety profile with pharmacodynamic activity. Repeated dose TRX518 monotherapy and in combination resulted in limited clinical responses associated with immune activation.

Mogamulizumab in Combination with Nivolumab in a Phase I/II Study of Patients with Locally Advanced or Metastatic Solid Tumors

PURPOSE

The aim of the study was to determine safety, antitumor activity, and pharmacodynamic profile of mogamulizumab, an anti-CCR4 monoclonal antibody targeting effector regulatory T cells (Treg) in combination with the checkpoint inhibitor nivolumab in patients with locally advanced or metastatic solid tumors.

PATIENTS AND METHODS

This was a multicenter, dose-finding (phase I), and dose expansion (phase II) study (NCT02705105) in patients with locally advanced or metastatic solid tumors. There were no dose-limiting toxicities in phase I with mogamulizumab 1 mg/kg every week for cycle 1 followed by 1 mg/kg every 2 weeks plus nivolumab 240 mg every 2 weeks intravenously, and cohort expansion occurred at this dose level.

RESULTS

All 114 patients treated with mogamulizumab 1 mg/kg plus nivolumab 240 mg in phases I (n = 4) and II (n = 110) were assessed for safety and efficacy. Mogamulizumab plus nivolumab showed acceptable safety and tolerability. Objective response rate was 10.5% [95% confidence interval (CI), 5.6-17.7; 3 complete and 9 partial responses]. Disease control rate was 36.8%. Median duration of response was 14.4 months. Median progression-free survival was 2.6 (95% CI, 2.3-3.1) months, and median overall survival was 9.5 (95% CI, 5.9-13.5) months.

CONCLUSIONS

Combination of mogamulizumab with nivolumab for treatment of patients with locally advanced or metastatic solid tumors did not result in enhanced efficacy. Tolerability of mogamulizumab 1 mg/kg plus nivolumab 240 mg was acceptable.

CTIM-05. A PHASE 1/2 STUDY OF THE COMBINATION OF INDOXIMOD AND TEMOZOLOMIDE FOR ADULT PATIENTS WITH TEMOZOLOMIDE-REFRACTORY PRIMARY HIGH-GRADE GLIOMAS

BACKGROUND

Optimal management of progressive high-grade gliomas (HGG) is not fully defined and outcomes are poor. Indoleamine 2,3-dioxygenase 1 (IDO1) is an enzyme which converts tryptophan to kynurenines, which contribute to the immunosuppresive tumor microenvironment (TME). Targeting the TME by inhibiting IDO1 is a strategy for potential improvement in survival in HGG.

METHODS

A phase 1/2 trial using the IDO1 inhibitor indoximod was conducted in progressive grade 3 and 4 gliomas. The phase 1 cmponent used a 3 + 3 design escalating indoximod from 600mg po BID to 1200mg po BID in conjunction with temozolomide (150 mg/m2, 5/28 days). The phase 2 component consisted of 3 cohorts: A) indoximod+temozolomide B) indoximod+temozolomide+bevacizumab (patients already on bevacizumab) C) indoximod+temozolomide+stereotactic radiosurgery (SRS). Patients were treated until progression or toxicity.

RESULTS

33.3% of patients developed indoximod TEAEs. There were no dose limiting toxicities in the phase 1 component (n=12). 1200 mg BID was established as the phase 2 dose of indoximod. In the phase 2 component (n=148) PFS6 was 74% (A), 93% (B), 70% (C). Median OS was 289 days [10.3 months](A), 159 days [5.7 months](B), 285 days [10.2 months](C). Correlative study results will be available for meeting presentation.

CONCLUSIONS

The IDO1 inhibitor indoximod proved safe and tolerable in conjunction with temozolomide, bevacizumab, and SRS in patients with progressive HGG. There was a trend toward better survival outcomes when indoximod was combined with temozolomide alone or temozolomide+SRS.

Phase II trial of the IDO pathway inhibitor indoximod plus pembrolizumab for the treatment of patients with advanced melanoma

Background

The indoleamine 2,3-dioxygenase (IDO) pathway is a key counter-regulatory mechanism that, in cancer, is exploited by tumors to evade antitumor immunity. Indoximod is a small-molecule IDO pathway inhibitor that reverses the immunosuppressive effects of low tryptophan (Trp) and high kynurenine (Kyn) that result from IDO activity. In this study, indoximod was used in combination with a checkpoint inhibitor (CPI) pembrolizumab for the treatment for advanced melanoma.

Methods

Patients with advanced melanoma were enrolled in a single-arm phase II clinical trial evaluating the addition of indoximod to standard of care CPI approved for melanoma. Investigators administered their choice of CPI including pembrolizumab (P), nivolumab (N), or ipilimumab (I). Indoximod was administered continuously (1200 mg orally two times per day), with concurrent CPI dosed per US Food and Drug Administration (FDA)-approved label.

Results

Between July 2014 and July 2017, 131 patients were enrolled. (P) was used more frequently (n=114, 87%) per investigator’s choice. The efficacy evaluable population consisted of 89 patients from the phase II cohort with non-ocular melanoma who received indoximod combined with (P).

The objective response rate (ORR) for the evaluable population was 51% with confirmed complete response of 20% and disease control rate of 70%. Median progression-free survival was 12.4 months (95% CI 6.4 to 24.9). The ORR for Programmed Death-Ligand 1 (PD-L1)-positive patients was 70% compared with 46% for PD-L1-negative patients. The combination was well tolerated, and side effects were similar to what was expected from single agent (P).

Conclusion

In this study, the combination of indoximod and (P) was well tolerated and showed antitumor efficacy that is worth further evaluation in selected patients with advanced melanoma.

Abstract 5535: SEA-CD40 is a non-fucosylated anti-CD40 antibody with potent pharmacodynamic activity in preclinical models and patients with advanced solid tumors

CD40 is a co-stimulatory receptor of the TNF receptor superfamily expressed on antigen presenting cells (APCs). Antibodies targeting CD40 may have therapeutic benefit via multiple mechanisms including innate immune activation that can support generation of antigen-specific, antitumor T cell responses, and binding to CD40-expressing cancer cells leading to antibody-mediated target cell killing. Multiple CD40-directed antibodies are in clinical development and differ by immunoglobulin isotype, affinity to CD40, and selectivity for FcγR-binding. These alterations could lead to differences in pharmacodynamic and antitumor activity.

SEA-CD40 is an agonistic non-fucosylated, humanized IgG1 monoclonal antibody directed against CD40. SEA-CD40 has enhanced FcγRIIIa binding (~10x greater than parent IgG1 antibody) that drives increased effector function, resulting in more potent immune stimulatory activity than antibodies with muted or selective FcγR binding. The enhanced effector function of SEA-CD40 may confer greater immune stimulation and antitumor activity relative to other CD40-directed therapeutics.

Preclinically, SEA-CD40 exposure results in a distinct signature of responses including activation of APCs, CD8+ and CD4+ T cells and NK cells, and targeted depletion of CD40+ B cells. SEA-CD40 demonstrates superior activity compared to other CD40-targeted antibodies in vitro and in vivo, suggesting that the enhanced effector function is critical for optimal immune cell agonism. For example, SEA-CD40 drove in vitro ADCC activity 100-fold above the parent antibody and exhibited robust ADCC with the low and high affinity FcγRIIIA genotype. At matched dose levels in cynomolgus monkeys, SEA-CD40 induced circulating cytokines and sustained B cell depletion that were up to 50-fold above that induced with the parent antibody. The SEA-CD40 signature of activation translates to increased antitumor activity as a single agent and in combination with standard of care treatments in preclinical models, suggesting the potential for beneficial combination therapy in the clinic.

The SEA-CD40 immune signature was confirmed by pharmacodynamic changes in an ongoing phase 1 clinical trial in patients with relapsed/refractory metastatic solid tumors (NCT02376699). SEA-CD40 treatment induced dose-dependent increases in circulating cytokines and chemokines associated with myeloid and lymphoid immune activation and trafficking. SEA-CD40 treatment also resulted in activation of CD4+ and CD8+ T cells and CD40-targeted B cell depletion in the periphery. These findings support continued clinical evaluation of SEA-CD40. The ongoing phase 1 clinical trial is actively enrolling and includes a cohort in pancreatic cancer assessing the combination of SEA-CD40, gemcitabine, nab-paclitaxel, and pembrolizumab.

Citation Format: Haley Neff-LaFord, Juneko E. Grilley-Olson, David C. Smith, Brendan Curti, Sanjay Goel, Timothy M. Kuzel, Svetomir N. Markovic, Olivier Rixe, David L. Bajor, Thomas F. Gajewski, Martin Gutierrez, Elisabeth I. Heath, John Thompson, Sahar Ansari, Shyra Gardai, Celine Jacquemont, Michael Schmitt, Andrew L. Coveler. SEA-CD40 is a non-fucosylated anti-CD40 antibody with potent pharmacodynamic activity in preclinical models and patients with advanced solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5535.

Abstract CT146: RGX-104, a first-in-class immunotherapy targeting the liver-X receptor (LXR): Initial results from the phase 1b RGX-104 plus docetaxel combination dose escalation cohorts

Background: RGX-104 is a small-molecule LXR agonist that modulates innate immunity via transcriptional activation of the ApoE gene. Binding of ApoE to its receptor LRP8 robustly inhibits angiogenesis and depletes myeloid derived suppressor cells (MDSC), thereby activating cytotoxic T-lymphocytes. MDSCs are associated with resistance to both checkpoint inhibitors (CPI) and chemotherapy, providing a rationale for combination therapy with RGX-104. We previously reported results of the RGX-104 monotherapy dose escalation for which 26 patients with refractory solid tumors were treated in 5 dose cohorts. On-target AEs included hyperlipidemia and neutropenia. Flow-cytometry demonstrated MDSC depletion with associated T cell activation, which correlated with clinical benefit. A 40% disease control rate (DCR; SD+PR) was observed with a confirmed partial response (PR) by irRC (>79% reduction in index lesions) in a patient with platinum-refractory small cell lung cancer (SCLC). Methods: Here, we present the safety, biomarker and efficacy results of the docetaxel combination arm of the RGX-104 trial. Cohort 1- RGX-104 80 mg BID, and docetaxel at 35 mg/m2 days 1, 8, and 15 of a 28-day cycle; Cohort 2- RGX-104 80 mg BID, 5 days-on/2 days-off (5/2), and docetaxel at 28 mg/m2 on above schedule. Cohort 3- RGX-104 100 mg BID (5/2), and docetaxel as per cohort 2. Results: As of February 7, 2020, 11 patients with refractory solid tumors have been treated in 3 dose escalation cohorts with RGX-104 plus docetaxel. AEs were consistent with the individual toxicity profiles of docetaxel and RGX-104, with neutropenia being the most common AE and dose-limiting in cohort 1. The 5/2 dosing regimen in cohorts 2 and 3 resulted in significantly fewer episodes of neutropenia and no DLTs, while maintaining pharmacodynamic effects including >50% sustained MDSC depletion. A 66% DCR was observed in 9 evaluable patients including 2 patients in cohort 2 with PRs, a CPI-refractory SCCHN patient and a CPI-refractory melanoma patient, who remains on treatment at 36 weeks. A patient with melanoma in Cohort 3 had an initial assessment of SD and continues on study at 14 weeks. Clinical responses were associated with increases in T cell activation markers exceeding that generally observed with RGX-104 alone (up to a 5-fold increase in total CD8 T cells, a 7-fold increase in LAG-3+ CD8 T cells, and a 75-fold induction of serum IFNγ). Conclusion: The safety profile and marked pharmacodynamic and clinical activity of the RGX-104/docetaxel combination in CPI-refractory patients supports further development of this regimen. Consequently, the RGX-104/docetaxel regimen will be evaluated in a Phase 1b/2 expansion cohort in patients with relapsed/refractory ES-SCLC/high grade-neuroendocrine tumors.

Citation Format: Emerson Lim, Erika P. Hamilton, Rebecca Redman, Michael A. Postow, Russell J. Schilder, Monica M. Mita, Alain C. Mita, Bartosz Chmielowski, James Strauss, Angela Jain, Shubham Pant, Olivier Rixe, Tomislav Dragovich, R. Donald Harvey, Igor Puzanov, Kevin B. Kim, Eric K. Rowinsky, Michael Szarek, Foster Gonsalves, Isabel Kurth, Celia Andreu, Robert W. Busby, David Darst, Masoud Tavazoie, Syed Raza, Narayan Lebaka16, Robert Wasserman, Gerald Falchook. RGX-104, a first-in-class immunotherapy targeting the liver-X receptor (LXR): Initial results from the phase 1b RGX-104 plus docetaxel combination dose escalation cohorts [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT146.

Assessment of effects of repeated oral doses of fedratinib on inhibition of cytochrome P450 activities in patients with solid tumors using a cocktail approach

PURPOSE

Fedratinib, an oral selective kinase inhibitor with activity against both wild type and mutationally activated Janus kinase 2, has been approved for the treatment of adult patients with intermediate-2 or high-risk myelofibrosis by the US Food and Drug Administration. In vitro studies indicated that fedratinib was an inhibitor of several cytochrome P450 (CYP) enzymes. The primary objective of this study was to evaluate the effects of repeated doses of fedratinib on the activity of CYP2D6, CYP2C19, and CYP3A4 in patients with solid tumors using a CYP probe cocktail.

METHODS

An open-label, one-sequence, two-period, two-treatment crossover study was conducted. Patients were administered a single oral dose cocktail of metoprolol (100 mg), omeprazole (20 mg), and midazolam (2 mg) used as probe substrates for CYP2D6, CYP2C19, and CYP3A4 enzyme activities, respectively, without fedratinib on Day -1 or with fedratinib on Day 15.

RESULTS

Coadministration of 500 mg once-daily doses of fedratinib for 15 days increased the mean area under the plasma concentration-time curve from time zero to infinity following a single-dose cocktail containing metoprolol (CYP2D6 substrate), omeprazole (CYP2C19 substrate), and midazolam (CYP3A4 substrate) by 1.77-fold (90% confidence interval [CI] 1.27-2.47) for metoprolol, 2.82-fold (90% CI 2.26-3.53) for omeprazole, and 3.84-fold (90% CI 2.62-5.63) for midazolam, respectively. The mean plasma Day 14/Day 1 ratio of 4β-hydroxycholesterol, an endogenous biomarker of CYP3A4 activity, was 0.59 (90% CI 0.54-0.66), suggesting a net inhibition of CYP3A4 by fedratinib.

CONCLUSION

Fedratinib is a weak inhibitor of CYP2D6, and a moderate inhibitor of CYP2C19 and CYP3A4. These results serve as the basis for dose modifications of these CYP substrate drugs when co-administered with fedratinib.

Tolerability and preliminary efficacy of BXQ-350 for refractory solid tumors and high-grade gliomas: First-in-human, first-in-class phase I trial

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Background: BXQ-350 is a first-in-class agent comprised of Saposin C (SapC) and dioleoyl phosphatidylserine (DOPS). SapC, a multifunctional lysosomal-activator glycoprotein that preferentially interacts with tumor cell phospholipids, has demonstrated anti-tumor effects in both in vitro and in vivo preclinical models. The tolerability and preliminary efficacy of BXQ-350 in the first-in-human study are summarized here. Methods: Eighty-six refractory solid tumor (ST) or high-grade glioma (HGG) patients age ≥18 (36F:50M, age 24-81) were enrolled in a 3-part first-in-human trial (NCT02859857) from 2016-2019 and received at least one dose of BXQ-350. Doses were administered via intravenous infusion during 28-day cycles until disease progression occurred. The previously reported part 1 dose escalation portion of the study (9 HGG, 9 ST patients) established the highest planned dose of 2.4mg/kg as safe but did not identify a maximum tolerated dose. The part 2 expansion cohort treated 37 patients (18 HGG and 19 ST) and an additional part 3 cohort treated 31 ST gastrointestinal (GI) patients, both at the 2.4 mg/kg dose level. Preliminary antitumor activity was evaluated (RECISTv1.1 or RANO). Results: There were no BXQ-350-related serious adverse events, dose limiting toxicities or withdrawals with the exception of 1 allergic type reaction. Three patients (Glioblastoma, Ependymoma, Appendiceal) demonstrated a partial response per RECIST/RANO. Two HGG patients with progressive radiologic enhancement were seen to have treatment effect at surgery, and hence considered to have stable disease. Seven patients (2 HGG, 3 GI, 2 other ST) remain on study and have received treatment for 9+ to 41+ months, with 5 patients treated for > 1 year. A continuing treatment protocol is planned in order to allow these patients to remain on BXQ-350 treatment. Conclusions: BXQ-350 was well tolerated with no significant dose-limiting toxicities at the highest planed dose level. Preliminary results indicate this novel agent demonstrated possible anti-tumor activity in refractory solid tumors and HGG. Clinical trial information: NCT03967093) .

Safety and pharmacokinetics of BXQ-350 in a phase 1a and 1b trial of solid tumors and high-grade glioma

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Background: BXQ-350 is composed of the multifunctional, lysosomal-activator protein Saposin C and phosphatidylserine lipid with demonstrated antitumor effects in vitro and in vivo. In this abstract we update the safety and pharmacokinetic (PK) profile based on an ongoing Phase 1 trial. Methods: BXQ-350 was administered in a Phase 1a dose-escalation trial (NCT02859857), and an ongoing Phase 1b trial (data cut off at max of 6 cycles, 01DEC2018) to refractory solid tumor/high-grade glioma patients (pts). In Phase 1a, pts received escalating IV BXQ-350 doses of 0.7, 1.1, 1.4, 1.8, or 2.4 mg/kg on days 1, 2, 3, 4, 5, 8, 10, 12, 15, 22 (cycle 1), 29 (cycle 2), and thereafter 28-day cycles. PK was assessed over a 24-hr period following the first dose. The Saposin C level was analyzed by ELISA and PK parameters were calculated using noncompartmental methods. Results: The 1a cohort of 18 pts (age 24-69) had a median of 3 cycles and 1b cohort of 20 pts (age 31-80) had median of 2 cycles with no treatment-related serious adverse events to date. Moderately severe related adverse events (AEs, n case, n events) are reported with serious non-related events. The most common treatment-related AE was fatigue (2 at dose 1.1, 2 at 1.8, 1 at 2.4mg/kg and 3 in 1b), at 2.4 mg/kg, 1 pt had moderate blood pressure elevation. Exposures in the 1.4 and 1.8 mg/kg cohorts were less than dose-proportional, likely due to higher clearance in those groups. The overall mean clearance and half-live values were 66.8 (mL/kg/h) and 4.03 h, respectively. Conclusions: BXQ-350 has had no serious related AEs during dose-escalation or in the on-going trial supporting a tolerable safety profile at 2.4 mg/kg. Clinical trial information: NCT02859857. [Table: see text]

Toxicity of PD-1/CTLA-4 inhibitor immunotherapy among elderly patients

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Background: The use of Immune check point inhibitors in advanced metastatic melanoma is becoming increasingly common especially in the elderly population. With metastatic melanoma being mostly a disease of the elderly, the safety and toxicity profile of immune check point inhibitors in this population group continues to remain controversial. Prior studies have hypothesized that due to reduced immune responses in the elderly, toxicity to immune check point inhibitors is expected to be low. In this study we aim to analyze the association of check point inhibitor induced immuno-toxicity with age. Methods: We analyzed 108 patients with stage 4 metastatic melanoma who were treated with anti-PD1 and/or anti-CTLA-4 immunotherapy. Out of these patients, 58 (53.7%) were 65 or more years old and 50 (46.3%) were < 65 years old. Overall, 64 (59.3%) patients had autoimmune side effects; 35 (60.3%) were 65 years or older and 29 (48%) were < 65 years old. The most common side effects were dermatitis (n = 22, 20.4%) and colitis (n = 21, 19.4%). Incidences of various autoimmune side effects were calculated in both groups (65 years or older and < 65 years old). Fisher exact test was used to calculate p values Results: There was a significant difference between the incidence of dermatitis between the two groups. (51.4% in 65 years or older and 24.1% in < 65 years old group, p = 0.04). The incidence of colitis was more in the 65 years or older group (37.1%) as compared to < 65 years group (31.1%) however results were not statistically significant (p = 0.79). Similarly, there was no significant difference in other autoimmune side effects including hepatitis, arthritis, pneumonitis, thyroiditis, hypophysitis, adrenalitis, anemia and thrombocytopenia between the two groups. Also, there was no significant difference in the incidence of different grades of side effects (1 to 4) between the two groups. Conclusions: Patients who are 65 years or older can safely tolerate immunotherapy as compared to patients < 65 years old but with an increased risk of dermatitis. These data should be validated by a larger study population.

Effect of antibiotic exposure in patients with metastatic melanoma treated with PD-1 inhibitor or CTLA-4 inhibitor or a combination of both

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Background: Pre clinical studies have demonstrated the effect of gut microbiome in the efficacy of immune check point inhibitors. The effect of antibiotic exposure to patients receiving PD-1/CTLA-4 inhibitor therapy has not been extensively studied, especially in metastatic melanoma. In this study, we demonstrate the effect of antibiotic exposure to metastatic melanoma patients receiving PD-1/CTLA-4 inhibitor therapy. Methods: We performed a retrospective analysis of 108 patients with stage 4 metastatic melanoma who received immunotherapy with PD-1 inhibitors or CTLA-4 inhibitors or combination of both between Nov 2010 and Oct 2017. Patients were divided into Abx(+) and Abx(-) groups that were defined as patients exposed or not exposed to antibiotics respectively. The time frame for antibiotic exposure was taken from 6 months prior to 1 month after initiation of immunotherapy. We compared progression free survival (PFS), overall survival (OS) and response rate (RR) between the two groups. RR was calculated based on the entire length of follow-up. PFS and OS were assessed using Kaplan-Meier estimates. Cox proportional hazards were used to calculate hazard ratios. Results: Out of 108 patients, 66 (61.1%) were men, with a mean age 64.6 ± 15.1 years. 46 (42.6%) patients were exposed to antibiotics of varied classes. Median PFS in abx(+) group [88 days (95%CI: 70, 104)] was shorter as compared to abx(-) group [322 days (95%CI: 191, 410), p < 0.0001)]. Patients in abx(-) group had a 68% (95%CI: 45, 82) reduced risk of progression within 200 days of immunotherapy initiation adjusting for sex, age and number of immunotherapy cycles (p < 0.0001) . Median OS in ab(+) group [294 days (95%CI: 198, 345)] was shorter as compared to abx(-) group [573 days (95%CI: 453, 677)], p < 0.0001. Response rate defined as percentage of patients whose cancer was stable or entered remission was 12.9% (95%CI: 5.7, 23.9) in abx(-) group as compared to 8.7% (95%CI: 2.4, 20.8) ab(+) group. Patients in abx(-) group had a 52% (95% CI: 24, 69) reduced risk of death adjusting for sex, age and number of immunotherapy cycles (p = 0.002). Conclusions: Antibiotic exposure is associated with poorer outcomes in patients with advanced metastatic melanoma being treated with PD-1/CTLA-4 inhibitors which is likely related to alteration of gut microbiome. Antibiotics should be prescribed with caution in patients undergoing treatment with immune check point inhibitors. These data should be validated in a larger patient population.

Phase I study combining olaparib and tremelimumab for the treatment of women with BRCA-deficient recurrent ovarian cancer

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Background: With evidence that BRCA dysfunction is associated with increased T cell recruitment to tumor sites, and that PARP-inhibition may increase the immunogenicity of tumor cells, we evaluated the combination of a PARP-inhibitor and CTLA4 immune checkpoint antibody in BRCA1- ovarian cancer models. Our results demonstrated significant therapeutic synergy and durable treatment responses in preclinical studies. Based on this, a Phase I study was conducted to assess the tolerability of this regimen in women with BRCA mutation-associated recurrent ovarian cancer. Methods: Eligibility criteria included a documented BRCA1 or BRCA2 germline mutations and a diagnosis of recurrent ovarian, tubal, or primary peritoneal cancer with measurable disease. Both platinum-sensitive and platinum resistant patients were eligible. Patients with prior exposure to PARP-inhibitors or to immune therapy with the exception of CTLA4 antibodies were also eligible. Exclusion criteria included current use of anti-inflammatory agents or a prior history of autoimmune disease. Treatment consisted of Olaparib at 300mg twice daily, as well as monthly infusions of Tremelimumab at a dose of 10mg/kg, with plans for a dose reduction if toxicity was encountered. Patients completing two full treatment cycles were evaluated for evidence of toxicity, particularly immune-related adverse events, to define a dose for Phase II testing. Results: Three women were treated at the starting dose of 300mg BID of Olaparib and 10mg/kg monthly of Tremelimumab for two cycles without evidence of any dose-limiting toxicities or grade 3 adverse events. All patients experienced grade 1 and 2 toxicities, including immune related toxicities consistent with prior studies of immune checkpoint inhibitors. All three patients showed evidence of treatment response by cycle 3 based on CA125 levels and a decrease in tumor size on CT scans. Conclusions: The combination of PARP-inhibition and CTLA-4 blockade is tolerable in heavily pre-treated women with recurrent BRCA-associated ovarian cancer. Preliminary results also demonstrate evidence of therapeutic effect, supporting ongoing evaluation of this regimen in Phase II trials. Clinical trial information: NCT02571725.

Effect of Renal Impairment on the Pharmacokinetics and Safety of Axitinib

BACKGROUND

Axitinib, an inhibitor of vascular endothelial growth factor (VEGF) receptors, is approved as second-line treatment for advanced renal cell carcinoma (RCC). Agents targeting the VEGF pathway may induce renal toxicities, which may be influenced by pre-existing renal dysfunction.

OBJECTIVE

The objective was to characterize axitinib pharmacokinetics and safety in patients with renal impairment.

PATIENTS AND METHODS

Effect of renal function (baseline creatinine clearance [CrCL]) on axitinib clearance was evaluated in a population pharmacokinetic model in 207 patients with advanced solid tumors who received a standard axitinib starting dose, and in 383 healthy volunteers. Axitinib safety according to baseline CrCL was assessed in previously treated patients with RCC (n = 350) who received axitinib in the phase 3 AXIS study.

RESULTS

Median axitinib clearance was 14.0, 10.7, 12.3, 7.81, and 12.6 L/h, respectively, in individuals with normal renal function (≥90 ml/min; n = 381), mild renal impairment (60-89 ml/min; n = 139), moderate renal impairment (30-59 ml/min; n = 64), severe renal impairment (15-29 ml/min; n = 5), and end-stage renal disease (<15 ml/min; n = 1). The population pharmacokinetic model adequately predicted axitinib clearance in individuals with severe renal impairment or end-stage renal disease. Grade ≥3 adverse events (AEs) were reported in 63 % of patients with normal renal function or mild impairment, 77 % with moderate impairment, and 50 % with severe impairment; study discontinuations due to AEs were 10 %, 11 %, and 0 %, respectively.

CONCLUSIONS

Axitinib pharmacokinetics and safety were similar regardless of baseline renal function; no starting-dose adjustment is needed for patients with pre-existing mild to severe renal impairment.

Safety and pharmacokinetics of cabazitaxel in patients with hepatic impairment: a phase I dose-escalation study

Purpose

Cabazitaxel has not been studied in patients with hepatic impairment (HI). This phase I study assessed cabazitaxel safety and pharmacokinetics in patients with HI.

Methods

Patients with advanced, non-hematologic cancer, and normal hepatic function (Cohort 1: C-1), or mild (C-2), moderate (C-3), severe (C-4) HI received cabazitaxel starting doses of 25, 20, 10, and 10 mg/m², respectively. Doses were escalated in patients with HI based on Cycle 1 dose-limiting toxicities (DLTs). Adverse events and the cabazitaxel pharmacokinetic profile were assessed.

Results

In C-2, three patients receiving cabazitaxel 25 mg/m² experienced DLTs; maximum tolerated dose (MTD) was 20 mg/m². In C-3, two patients receiving 20 mg/m² experienced DLTs; MTD was 15 mg/m². C-4 was discontinued early due to DLTs. The most frequent cabazitaxel-related, grade 3–4 toxicity was neutropenia (42%). Cabazitaxel clearance normalized to body surface area (CL/BSA) was lower in C-1 (geometric mean [GM] 13.4 L/h/m²) than expected (26.4 L/h/m²), but similar in C-2 (23.5 L/h/m²) and C-3 (27.9 L/h/m²). CL/BSA in C-4 was 18.1 L/h/m². Compared with C-2, CL/BSA increased 19% in C-3 (GM ratio 1.19; 90% CI 0.74–1.91), but decreased 23% in C-4 (0.77; 0.39–1.53). Cabazitaxel free fraction was unaltered. No significant correlation was found between grade 3–4 toxicities and pharmacokinetic parameters.

Conclusions

Mild–moderate HI did not cause substantial decline in cabazitaxel clearance. Cabazitaxel dose reductions in patients with mild–moderate HI, and a contraindication in patients with severe HI, are justified based on safety data.

High-Dose Sirolimus and Immune-Selective Pentostatin plus Cyclophosphamide Conditioning Yields Stable Mixed Chimerism and Insufficient Graft-versus-Tumor Responses

PURPOSE

We hypothesized that lymphoid-selective host conditioning and subsequent adoptive transfer of sirolimus-resistant allogeneic T cells (T-Rapa), when combined with high-dose sirolimus drug therapy in vivo, would safely achieve antitumor effects while avoiding GVHD.

EXPERIMENTAL DESIGN

Patients (n = 10) with metastatic renal cell carcinoma (RCC) were accrued because this disease is relatively refractory to high-dose conditioning yet may respond to high-dose sirolimus. A 21-day outpatient regimen of weekly pentostatin (P; 4 mg/m(2)/dose) combined with daily, dose-adjusted cyclophosphamide (C; ≤200 mg/d) was designed to deplete and suppress host T cells. After PC conditioning, patients received matched sibling, T-cell-replete peripheral blood stem cell allografts, and high-dose sirolimus (serum trough target, 20-30 ng/mL). To augment graft-versus-tumor (GVT) effects, multiple T-Rapa donor lymphocyte infusions (DLI) were administered (days 0, 14, and 45 posttransplant), and sirolimus was discontinued early (day 60 posttransplant).

RESULTS

PC conditioning depleted host T cells without neutropenia or infection and facilitated donor engraftment (10 of 10 cases). High-dose sirolimus therapy inhibited multiple T-Rapa DLI, as evidenced by stable mixed donor/host chimerism. No antitumor responses were detected by RECIST criteria and no significant classical acute GVHD was observed.

CONCLUSIONS

Immune-selective PC conditioning represents a new approach to safely achieve alloengraftment without neutropenia. However, allogeneic T cells generated ex vivo in sirolimus are not resistant to the tolerance-inducing effects of in vivo sirolimus drug therapy, thereby cautioning against use of this intervention in patients with refractory cancer.

Phosphatidylserine-selective targeting and anticancer effects of SapC-DOPS nanovesicles on brain tumors

Brain tumors, either primary (e.g., glioblastoma multiforme) or secondary (metastatic), remain among the most intractable and fatal of all cancers. We have shown that nanovesicles consisting of Saposin C (SapC) and dioleylphosphatidylserine (DOPS) are able to effectively target and kill cancer cells both in vitro and in vivo. These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature. In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity. Second, we demonstrate that SapC-DOPS selectively targets brain metastases-forming cancer cells both in vitro, in co-cultures with human astrocytes, and in vivo, in mouse models of brain metastases derived from human breast or lung cancer cells. Third, we demonstrate that SapC-DOPS nanovesicles have cytotoxic activity against metastatic breast cancer cells in vitro, and prolong the survival of mice harboring brain metastases. Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors.