Randomized phase III study of docetaxel plus bavituximab in previously treated advanced non-squamous non-small-cell lung cancer

Background

Bavituximab is a monoclonal antibody that targets phosphatidylserine in the presence of β2 glycoprotein 1 (β2GP1) to exert an antitumor immune response. This phase III trial determined the efficacy of bavituximab combined with docetaxel in patients with previously treated advanced non-small-cell lung cancer (NSCLC).

Patients and methods

Key eligibility criteria included advanced non-squamous NSCLC with disease progression after treatment with platinum-based doublet chemotherapy, evidence of disease control after at least two cycles of first-line therapy, presence of measurable disease, ECOG performance status 0 or 1, adequate bone marrow and organ function, and no recent history of clinically significant bleeding. Eligible patients were randomized 1 : 1 to receive up to six 21-day cycles of docetaxel plus either weekly bavituximab 3 mg/kg or placebo until progression or toxicity. The primary end point was overall survival (OS).

Results

A total of 597 patients were enrolled. Median OS was 10.5 months in the docetaxel + bavituximab arm and was 10.9 months in the docetaxel + placebo arm (HR 1.06; 95% CI 0.88-1.29; P = 0.533). There was no difference in progression-free survival (HR 1.00; 95% CI 0.82-1.22; P = 0.990). Toxicities were manageable and similar between arms. In subset analysis, among patients with high baseline serum β2GP1 levels ≥200 µg/ml, a nonsignificant OS trend favored the bavituximab arm (HR 0.82; 95% CI 0.63-1.06; P = 0.134). Among patients who received post-study immune checkpoint inhibitor therapy, OS favored the bavituximab arm (HR 0.46; 95% CI 0.26-0.81; P = 0.006).

Conclusions

The combination of bavituximab plus docetaxel is not superior to docetaxel in patients with previously treated advanced NSCLC. The addition of bavituximab to docetaxel does not meaningfully increase toxicity. The potential benefit of bavituximab observed in patients with high β2GP1 levels and in patients subsequently treated with immune checkpoint inhibitors requires further investigation.

Clinical trial number

NCT01999673.

Recognition of Ii-Key/MHC class II epitope hybrids derived from proinsulin and GAD peptides by T cells in type 1 diabetes

In order to determine whether the Ii-Key technology can enhance the presentation of specific epitopes associated with type 1 diabetes, we have designed and synthesized a series of Ii-Key/proinsulin and GAD epitope hybrid peptides. Peptides of proinsulin and GAD shown to be recognized by CD4+ T cells of type 1 diabetes patients have been selected from the literature and modified with Ii-Key. A total of 23 Caucasian type 1 diabetes subjects and 17 normal subjects as controls were included in the study. Reactive T cells were identified using an IFN-γ ELISPOT assay. We selected 5 proinsulin and 5 GAD epitopes. Regarding the activity of the proinsulin Ii-Key hybrids, 3 out of 15 patients (20%) demonstrated a positive response to one or more Ii-Key hybrid peptides compared to no responders in the control subjects. Two out of 8 patients demonstrated a positive response to one or more Ii-Key/GAD65 hybrids. Proinsulin Ii-Key hybrids and peptides were recognized only by DR3/DR4 0302+ve diabetic patients. Control subjects showed no detectable response to stimulation with Ii-Key hybrids or peptides, neither for proinsulin nor GAD65. We have now shown that the use of Ii-Key-modified MHC class II epitopes, derived from proteins associated with insulin-secreting cells, can detect the presence of specifically activated CD4+ T helper cells with greater sensitivity than unmodified epitopes in the standard ELISPOT assay. The use of these technologies may be of use in identifying patients at the earliest stages of type 1 diabetes.

Results from the first phase I clinical study of the novel Ii-Key/HER2/neu(776–790) hybrid peptide vaccine in patients with prostate cancer

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Background: HER-2/neu(776–790) represents an immunogenic epitope from the HER-2/neu oncoprotein whose immunogenicity is highly potentiated upon linkage with the Ii-Key moiety (LRMK) from the MHC class II invariant chain. Herein, we present the results of the first phase I clinical trial of the Ii-Key/HER-2/neu(776–790) (AE37) vaccine in patients (pts) with prostate cancer. Methods: Androgen-dependent (AD) and androgen-independent (AI) pts with HER-2/neu+ (IHC: 1–3) prostate adenocarcinomas were eligible. Concomitant medication with bicatulamide and LHRH or docitaxel was allowed. All pts received 6 monthly vaccinations with the AE37 vaccine (500 μg of AE37 plus 125 μg of GM-CSF) administered in two doses intradermally 5cm apart in the same extremity for each vaccination cycle. Immunologic responses were measured monthly in vitro by the IFNγ-based ELISPOT assay using pts’ PBMC and in vivo at the beginning and end of immunizations using DTH. Local dermal reactions were also measured after each vaccination. Results: Eligible pts [AD (n=18), AI (n=10)] were at stages T1–3N0M0, GS: 3–7 (n=18); T1–3N+M0, GS: 6–7 (n=2); T1–3N0M+, GS: 6–9 (n=4) and T1–3N+M+, GS: 6–9 (n=4). All pts had standard treatment prior to vaccinations, including surgery (S) (n=9); hormonal treatment (HT) (n=4); S+HT (n=6); S+HT+radiotherapy (RT); (n=2); S+chemotherapy (CH) (n=2); HT+RT (n=2); CH (n=3) and S+HT+CH (n=2). During vaccinations, 11 pts were free of any treatment, while 5 pts who had progressive disease received additional chemotherapy; the remainder received HT alone or combined with RT. 25 pts completed all vaccinations. Toxicity and side effects beyond grade-2 were not observed. GM-CSF was reduced by 50% for subsequent vaccinations when a local reaction of 100mm or greater was observed. DTH reactions to the parent HER-2/neu(776–790) peptide were increased (compared to pre-vaccination) for all pts, while approximately half the pts responded with significantly increased IFNγ responses to AE37 and/or parent HER-2/neu(776–790) peptide in at least 2 sequential vaccination cycles. Conclusions: The AE37 vaccine is safe and well tolerated. AE37 is also capable of eliciting potent and specific immunologic responses in prostate cancer pts.

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Generating MHC Class II+/Ii- phenotype after adenoviral delivery of both an expressible gene for MHC Class II inducer and an antisense Ii-RNA construct in tumor cells

Tumor cells engineered by gene transduction to be MHC Class II+/Ii- are novel APCs capable of presenting endogenous tumor antigen epitopes to activate T helper cells. The MHC Class II+/Ii- tumor cell phenotype is created by transfecting genes for either CIITA or IFN-gamma, and inhibiting induced Ii mRNA by an Ii reverse gene construct (Ii-RGC). Adenoviral vectors are preferred for the delivery of such genes because of high infection efficiency and ubiquity of the adenoviral receptor on many cell types and tumors. Here we show that at 5 MOI (multiplicity of infection), recombinant adenoviruses with CIITA or IFN-gamma genes converted virtually all MC-38 colon adenocarcinoma cells and Renca renal carcinoma cells in culture to MHC Class II+/Ii+ cells. A single recombinant adenovirus with both genes for IFN-gamma and Ii-RGC (rAV/IFN-gamma/Ii-RGC) efficiently induced the MHC Class II+/Ii- phenotype. Injection of tumor nodules with rAV/Ii-RGC and rAV/CIITA/IFN-gamma combined with a suboptimal dose of rAV/IL-2 induced a potent antitumor immune response. The methods are adaptable for producing enhanced genetic vaccines, attenuated virus vaccines (eg, vaccinia), and ex vivo cell-based vaccines (dendritic and tumor cells).