Phase I Trial Characterizing the Pharmacokinetic Profile of N-803, a Chimeric IL-15 Superagonist, in Healthy Volunteers

The oncotherapeutic promise of IL-15, a potent immunostimulant, is limited by a short serum t _1/2 The fusion protein N-803 is a chimeric IL-15 superagonist that has a >20-fold longer in vivo t _1/2 versus IL-15. This phase 1 study characterized the pharmacokinetic (PK) profile and safety of N-803 after s.c. administration to healthy human volunteers. Volunteers received two doses of N-803, and after each dose, PK and safety were assessed for 9 d. The primary endpoint was the N-803 PK profile, the secondary endpoint was safety, and immune cell levels and immunogenicity were measures of interest. Serum N-803 concentrations peaked 4 h after administration and declined with a t _1/2 of ∼20 h. N-803 did not cause treatment-emergent serious adverse events (AEs) or grade ≥3 AEs. Injection site reactions, chills, and pyrexia were the most common AEs. Administration of N-803 was well tolerated and accompanied by proliferation of NK cells and CD8⁺ T cells and sustained increases in the number of NK cells. Our results suggest that N-803 administration can potentiate antitumor immunity.

Phase I Trial of N-803, an IL15 Receptor Agonist, with Rituximab in Patients with Indolent Non-Hodgkin Lymphoma

PURPOSE

N-803 is an IL15 receptor superagonist complex, designed to optimize in vivo persistence and trans-presentation, thereby activating and expanding natural killer (NK) cells and CD8⁺ T cells. Monoclonal antibodies (mAbs) direct Fc receptor-bearing immune cells, including NK cells, to recognize and eliminate cancer targets. The ability of IL15R agonists to enhance tumor-targeting mAbs in patients has not been reported previously.

PATIENTS AND METHODS

Relapsed/refractory patients with indolent non-Hodgkin lymphoma were treated with rituximab and intravenous or subcutaneous N-803 on an open-label, dose-escalation phase I study using a 3+3 design (NCT02384954). Primary endpoint was maximum tolerated dose. Immune correlates were performed using multidimensional analysis via mass cytometry and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) which simultaneously measures protein and single-cell RNA expression.

RESULTS

This immunotherapy combination was safe and well tolerated and resulted in durable clinical responses including in rituximab-refractory patients. Subcutaneous N-803 plus rituximab induced sustained proliferation, expansion, and activation of peripheral blood NK cells and CD8 T cells, with increased NK cell and T cells present 8 weeks following last N-803 treatment. CITE-seq revealed a therapy-altered NK cell molecular program, including enhancement of AP-1 transcription factor. Furthermore, the monocyte transcriptional program was remodeled with enhanced MHC expression and antigen-presentation genes.

CONCLUSIONS

N-803 combines with mAbs to enhance tumor targeting in patients, and warrants further investigation in combination with immunotherapies.

The IL-15 receptor agonist N-803 combined with the anti-CD20 monoclonal antibody rituximab expands NK and CD8 T cells and alters single cell immune transcriptomes in a phase 1 clinical trial in lymphoma

IL-15 is a cytokine that is crucial for the development, survival, and activation of NK cells, and pre-clinical studies demonstrated that IL-15 augments antibody-dependent cellular cytotoxicity. We hypothesized that IL-15 would augment anti-CD20 mAb (rituximab)-directed responses in patients with indolent non-Hodgkin’s lymphoma. To address this, we performed a first-in-human combination clinical trial of the IL-15 super agonist N-803 with rituximab, and investigated the impact of this novel immune combination on NK, CD8 T cells, and monocytes. The combination was safe and demonstrated clinical activity, including in patients refractory to rituximab. To understand the in vivo impact on the patients’ immune systems, we performed mass cytometry and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq), which measures single-cell RNA-seq and cell surface proteins simultaneously. N-803 induced expansion of NK (12.5-fold) and CD8 T cells (2-fold) in serial blood samples and upregulated CD38, chemokines, and MHC class II family member expression while maintaining CD16 expression on NK. On CD56dim NK, N-803 increased activating receptors, decreased CD57, and modulated transcription factor expression (AP-1, Eomes, CEBPB/D). CD56bright NK cells were primed, with increases in granzyme A, B, and K. Therapy also markedly altered the monocyte compartment, significantly upregulating type 1 interferon and interferon gamma pathways in CD14+ monocytes, and decreased the percent of CD16+ monocytes, suggestive of potential trafficking to the tumor. Collectively, our data demonstrates that N-803 plus rituximab induces complex immune activation, and supports N-803 combination with other mAbs and immunotherapies.

Phase I Trial of ALT-803, A Novel Recombinant IL15 Complex, in Patients with Advanced Solid Tumors

Purpose: IL15 induces the activation and proliferation of natural killer (NK) and memory CD8⁺ T cells and has preclinical antitumor activity. Given the superior activity and favorable kinetics of ALT-803 (IL15N72D:IL15RαSu/IgG1 Fc complex) over recombinant human IL15 (rhIL15) in animal models, we performed this first-in-human phase I trial of ALT-803 in patients with advanced solid tumors.Patients and Methods: Patients with incurable advanced melanoma, renal cell, non-small cell lung, and head and neck cancer were treated with ALT-803 0.3 to 6 μg/kg weekly intravenously or 6 to 20 μg/kg weekly subcutaneously for 4 consecutive weeks, every 6 weeks. Immune correlates included pharmacokinetics, immunogenicity, and lymphocyte expansion and function. Clinical endpoints were toxicity and antitumor activity.Results: Twenty-four patients were enrolled; 11 received intravenous and 13 received subcutaneous ALT-803. Of these patients, nine had melanoma, six renal, three head and neck, and six lung cancer. Although total lymphocyte and CD8⁺ T-cell expansion were modest, NK cell numbers rose significantly. Neither anti-ALT-803 antibodies nor clinical activity were observed. Overall, ALT-803 was well tolerated, with adverse effects including fatigue and nausea most commonly with intravenous administration, whereas painful injection site wheal was reported most commonly with subcutaneous ALT-803.Conclusions: Subcutaneous ALT-803 produced the expected NK cell expansion and was well tolerated with minimal cytokine toxicities and a strong local inflammatory reaction at injection sites in patients with advanced cancer. These data, together with compelling evidence of synergy in preclinical and clinical studies, provide the rationale for combining ALT-803 with other anticancer agents. Clin Cancer Res; 24(22); 5552-61. ©2018 AACR.

ALT-803, an IL-15 superagonist, in combination with nivolumab in patients with metastatic non-small cell lung cancer: a non-randomised, open-label, phase 1b trial

BACKGROUND

Immunotherapy with PD-1 or PD-L1 blockade fails to induce a response in about 80% of patients with unselected non-small cell lung cancer (NSCLC), and many of those who do initially respond then develop resistance to treatment. Agonists that target the shared interleukin-2 (IL-2) and IL-15Rβγ pathway have induced complete and durable responses in some cancers, but no studies have been done to assess the safety or efficacy of these agonists in combination with anti-PD-1 immunotherapy. We aimed to define the safety, tolerability, and activity of this drug combination in patients with NSCLC.

METHODS

In this non-randomised, open-label, phase 1b trial, we enrolled patients (aged ≥18 years) with previously treated histologically or cytologically confirmed stage IIIB or IV NSCLC from three academic hospitals in the USA. Key eligibility criteria included measurable disease, eligibility to receive anti-PD-1 immunotherapy, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received the anti-PD-1 monoclonal antibody nivolumab intravenously at 3 mg/kg (then 240 mg when US Food and Drug Administration [FDA]-approved dosing changed) every 14 days (either as new treatment or continued treatment at the time of disease progression) and the IL-15 superagonist ALT-803 subcutaneously once per week on weeks 1-5 of four 6-week cycles for 6 months. ALT-803 was administered at one of four escalating dose concentrations: 6, 10, 15, or 20 μg/kg. The primary endpoint was to define safety and tolerability and to establish a recommended phase 2 dose of ALT-803 in combination with nivolumab. Analyses were per-protocol and included any patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, number NCT02523469; phase 2 enrolment of patients is ongoing.

FINDINGS

Between Jan 18, 2016, and June 28, 2017, 23 patients were enrolled and 21 were treated at four dose levels of ALT-803 in combination with nivolumab. Two patients did not receive treatment because of the development of inter-current illness during enrolment, one patient due to leucopenia and one patient due to pulmonary dysfunction. No dose-limiting toxicities were recorded and the maximum tolerated dose was not reached. The most common adverse events were injection-site reactions (in 19 [90%] of 21 patients) and flu-like symptoms (15 [71%]). The most common grade 3 adverse events, occurring in two patients each, were lymphocytopenia and fatigue. A grade 3 myocardial infarction occurred in one patient. No grade 4 or 5 adverse events were recorded. The recommended phase 2 dose of ALT-803 is 20 μg/kg given once per week subcutaneously in combination with 240 mg intravenous nivolumab every 2 weeks.

INTERPRETATION

ALT-803 in combination with nivolumab can be safely administered in an outpatient setting. The promising clinical activity observed with the addition of ALT-803 to the regimen of patients with PD-1 monoclonal antibody relapsed and refractory disease shows evidence of anti-tumour activity for a new class of agents in NSCLC.

FUNDING

Altor BioScience (a NantWorks company), National Institutes of Health, and Medical University of South Carolina Hollings Cancer Center.

A multicenter, randomized, open-label, active-comparator trial to determine the efficacy, safety, and pharmacokinetics of intravenous ibuprofen for treatment of fever in hospitalized pediatric patients

BACKGROUND

Oral antipyretics are commonly used to treat pediatric patients who develop fevers. However, patients presenting to the emergency department or undergoing surgery are frequently unable to tolerate oral antipyretics. Rectal formulations are available; however, this route of administration is unpredictable. The main objectives of this randomized controlled study was to evaluate the efficacy and safety of single or multiple doses of intravenous ibuprofen to acetaminophen (oral or suppository) in pediatric patients with fever and to assess plasma ibuprofen concentrations.

METHODS

This multi-center study was conducted in hospitalized patients, ≤ 16 years, with a new onset of fever ≥ 38.3°C. Patients were randomly assigned to receive either 10 mg/kg intravenous ibuprofen or acetaminophen. Study drug was administered at hour 0, and thereafter every 4 h as needed, up to 5 days. The primary outcome was to evaluate the effect of a single dose of intravenous ibuprofen compared to acetaminophen in reducing temperature in the first 2 h after administration. Data were compared using an analysis of variance model for continuous measurements and Cochran-Mantel-Haenszel test of general association for categorical data. A two-sided testing was used and a p-value ≤ 0.05 was considered significant.

RESULTS

A total of 103 patients received study medication. Intravenous ibuprofen resulted in a greater reduction in temperature as measured by the area under the change from baseline at 2 h (p = 0.005) and 4 h (<0.001); in a greater reduction in change from baseline temperature compared to treatment with acetaminophen, and it reduced fever throughout a 24 h dosing period. There were no differences in safety parameters or serious adverse events.

CONCLUSIONS

A single 10 mg/kg dose of intravenous ibuprofen provided a significant reduction of temperature for febrile pediatric patients compared to those that received 10 mg/kg acetaminophen at 2 h and 4 h post-treatment. A reduction in temperature was also demonstrated over 24 h; however the reduction was not considered statically significant. Intravenous ibuprofen provides an effective option for reducing fever in hospitalized pediatric patients.

TRIAL REGISTRATION

The study was registered on ClinicalTrials.gov on 26 October 2009, Study Identifier: NCT01002573.

Dose comparison of conivaptan (Vaprisol®) in patients with euvolemic or hypervolemic hyponatremia--efficacy, safety, and pharmacokinetics

PURPOSE

This study aimed to evaluate the efficacy, safety, and pharmacokinetics of 20 and 40 mg/day conivaptan (Vaprisol®) in patients with hypervolemic or euvolemic hyponatremia.

METHODS

Hyponatremic patients - serum sodium (sNa) ≤130 mEq/L - received either 20 or 40 mg/day of conivaptan for 4 days, following an initial 20 mg loading dose. Efficacy was evaluated by the magnitude and extent of change in sNa. Safety was evaluated by the incidence of adverse events, changes in vital signs and laboratory parameters, rate of sNa correction, and frequency of infusion-site reactions. Pharmacokinetic parameters were also measured.

RESULTS

A total of 37 patients received 20 mg/day and 214 patients received 40 mg/day conivaptan. Baseline-adjusted sNa-area under the concentration-time curve increased by an average of 753.8±499.9 mEq·hr/L (20 mg/day) and 689.2±417.3 mEq·hr/L (40 mg/day) over the course of the 4-day treatment period. The majority of patients in both treatment groups achieved a 4 mEq/L increase in sNa over baseline in ~24 hours (82.5%). Average increase in sNa after 4 days was ~10 mEq/L, varying with dosage level and baseline volume status. Treatment success (normal sNa or increase of ≥6 mEq/L) was attained by 70.3% of patients in the 20 mg/day group and 72.0% in the 40 mg/day group.

CONCLUSION

Both 20 and 40 mg/day doses of conivaptan are efficacious in increasing sNa over 4 days of treatment with no observed increase in the frequency of adverse events or specific infusion-site reactions using the higher dose. The pharmacokinetic parameters of both doses were similar to what has been reported previously, exhibiting greater-than-dose-proportional plasma concentrations.

An integrated safety analysis of intravenous ibuprofen (Caldolor(®)) in adults

Intravenous (IV) nonsteroidal anti-inflammatory drugs such as IV ibuprofen are increasingly used as a component of multimodal pain management in the inpatient and outpatient settings. The safety of IV ibuprofen as assessed in ten sponsored clinical studies is presented in this analysis. Overall, 1,752 adult patients have been included in safety and efficacy trials over 11 years; 1,220 of these patients have received IV ibuprofen and 532 received either placebo or comparator medication. The incidence of adverse events (AEs), serious AEs, and changes in vital signs and clinically significant laboratory parameters have been summarized and compared to patients receiving placebo or active comparator drug. Overall, IV ibuprofen has been well tolerated by hospitalized and outpatient patients when administered both prior to surgery and postoperatively as well as for nonsurgical pain or fever. The overall incidence of AEs is lower in patients receiving IV ibuprofen as compared to those receiving placebo in this integrated analysis. Specific analysis of hematological and renal effects showed no increased risk for patients receiving IV ibuprofen. A subset analysis of elderly patients suggests that no dose adjustment is needed in this higher risk population. This integrated safety analysis demonstrates that IV ibuprofen can be safely administered prior to surgery and continued in the postoperative period as a component of multimodal pain management.