Abstract P2-09-12: Perilymphatic IRX-2 cytokine therapy to enhance tumor infiltrating lymphocytes (TILs) and PD-L1 expression preceding curative-intent therapy in early stage breast cancer (ESBC)

Background: Cytokines are being explored as a therapeutic strategy to modulate the tumor microenvironment and facilitate immunotherapy benefit in breast cancer. Here, we investigate a locoregional therapeutic approach whereby cytokines (IRX-2) are administered into the subcutaneous peri-areolar tissue (in an anatomic distribution similar to sentinel lymph node mapping) to facilitate immune cell recruitment/activation within the draining lymph nodes and tumor in ESBC. IRX-2 is derived from ex vivo phytohemagglutinin-stimulated lymphocytes and contains multiple cytokines including IL-1β, IL-2, TNF-α, IFN-γ, IL-6, IL-8, and GM-CSF, with stable concentrations from lot to lot. Preclinically, IRX-2 activates T-cells and natural killer (NK) cells, facilitates antigen presentation, and enhances activity of anti-PD-1/L1 in a SCC7 model. In a preceding head/neck squamous cell carcinoma phase I trial, perilymphatic IRX-2 was safe and increased TILs. Here, we report the final clinical results of a phase Ib trial evaluating the feasibility and immunologic activity of IRX-2 in ESBC.

Methods: Beginning 21 days prior to surgical resection, enrolled operable patients with stage I-III ESBC (all subtypes) received the pre-operative IRX-2 regimen consisting of a single low-dose cyclophosphamide (300 mg/m2 to facilitate T-regulatory cell depletion), followed by 10 days of subcutaneous peri-areolar IRX-2 injections into the affected breast (1 mL × 2 at tumor axis and at 90°). Endpoints were feasibility (primary endpoint), stromal TIL (sTIL) count (pre-treatment versus post-treatment, blinded average of two pathologist reads using San Antonio H&E sTIL guidelines), PD-L1 expression (Nanostring) and enumeration of peripheral immune cells by flow cytometry.

Results: All patients (n=16/16) completed and tolerated the regimen with no surgical delays or treatment-attributed grade III/IV toxicities. Common adverse events (occurring in >15% subjects) attributed to IRX-2 injections were: injection site reaction (grade 1, n=8/16), bruising (grade 1, n=7/16), and pain (grade 1, n=3/16). Common adverse events attributed to low-dose cyclophosphamide were: fatigue (grade 1, n=5/16) and nausea (grade 1/2, n=3/16). Treatment was associated with an increase in sTIL score (Wilcoxon signed-rank p=.04), with 4/10 sTIL-low tumors (0-10% score) re-categorized to sTIL-moderate (11-50% score). Increases in PD-L1 RNA expression were observed (Wilcoxon signed-rank p=.04) in 12/16 tumors (median 57% increase, range: -53% to 185% increase), as well as increases in Nanostring NK and Th1 cell signatures. In blood, increases in CD4 and CD8 effector T-cell activation (ICOS, HLA-DR, and CD38) and T-reg depletion were observed.

Conclusions: IRX-2 was well tolerated with preliminary evidence of sTIL increase, PD-L1 upregulation, and peripheral lymphocyte activation. Based upon these data and preclinical evaluations demonstrating synergy with checkpoint inhibition, the IRX-2 regimen is being evaluated for clinical efficacy in conjunction with pembrolizumab and neoadjuvant chemotherapy (doxorubicin, cyclophosphamide, paclitaxel) in patients with stage II-III triple negative breast cancer.

Citation Format: Pucilowska J, Egan JE, Berinstein NL, Moxon N, Aliabadi-Wahle S, Imatani JH, Conlin A, Acheson A, Massimino K, Martel M, Campbell M, Wu Y, Sun Z, Redmond W, Shah M, Urba WJ, Page DB. Perilymphatic IRX-2 cytokine therapy to enhance tumor infiltrating lymphocytes (TILs) and PD-L1 expression preceding curative-intent therapy in early stage breast cancer (ESBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-12.

Use of Blue Citrus, a Chinese herbal remedy, to reduce side effects of aromatase inhibitors

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Background: Aromatase inhibitors are widely used in treatment of estrogen receptor positive breast cancer. Many patients experience significant arthralgias, which may lead to early cessation of therapy. Blue Citrus, a mix of Chinese herbs formulated in our community, had anecdotal reports of success in alleviating these symptoms. We objectively evaluated its activity in symptomatic patients.

Methods: Breast cancer patients with significant arthralgia on aromatase inhibitors were enrolled in a prospective fashion to a double blind crossover placebo controlled trial. Each patient received either Blue Citrus (BC+P) or a placebo (P+BC) for three months and then crossed over to the opposite treatment for an additional three months. Symptoms were measured over the course of treatment.

Results: A total of 37 patients enrolled on the study. There were 6 early withdrawals, which left 31 evaluable patients. Visual Analogue Score (VAS) for both groups was similar at baseline at 4.9 and 5.1 for the BC+P and P+BC groups, respectively. At 30 days the BC+P score was 3.4 vs. the P+BC of 4.7 showing clearly improved symptom control in the BC+P group. The P+BC group did however approach the BC+P group by 90 days. At crossover the BC+P group experienced a spike in symptomology when changed to placebo that didn’t appear for the P+BC group. When compared to baseline, mean VAS score on Blue Citrus was 2.98 (p=0.001) versus mean VAS score on placebo 3.92 (p=0.0203). By study end (180 days) the VAS scores for both groups were closer at 2.6 BC+P vs. 3.0 for P+BC but BC+P still maintained lower VAS scores.

Conclusions: Blue Citrus improved symptoms associated with aromatase inhibitor use. Patients who received Blue Citrus in the first arm had rapid improvement in symptoms and experienced return of symptoms when converted to placebo. All patients averaged lower VAS scores on Blue Citrus however at 6 months the difference between the arms became less pronounced.