News

Imiquimod/Abraxane Combo Effective for Skin Mets


 

FROM THE SAN ANTONIO BREAST CANCER SYMPOSIUM

SAN ANTONIO – The combination of topical 5% imiquimod plus systemic nanoparticle albumin-bound paclitaxel showed excellent clinical efficacy and was well tolerated for the treatment of cutaneous metastases of breast cancer in a phase II study.

Among the 11 patients who were able to complete the novel combined chemoimmunotherapy regimen, 5 had a complete response, meaning 100% clearance of treated skin lesions at week 24.

In addition, one patient had a partial response, defined as a greater than 50% reduction in the size of the largest treated lesion. Four patients had stable disease, with less than 50% reductions in lesion size. One patient experienced progressive disease, with a 25% increase in target lesion size, Dr. Lupe G. Salazar reported at the San Antonio Breast Cancer Symposium.

Fifteen heavily pretreated breast cancer patients were enrolled in the single-arm, nonrandomized study. All had skin metastases no longer amenable to standard therapies.

The chemoimmunotherapy regimen consisted of three treatment cycles. Each 4-week cycle consisted of application of topical 5% imiquimod to target cutaneous lesions on 4 days per week plus systemic albumin-bound paclitaxel (Abraxane) at 100 mg/m2 on days 1, 8, 15, and 28, explained Dr. Salazar of the University of Washington, Seattle.

Treatment-related toxicities included neutropenia, lymphopenia, anemia, nausea, and fatigue; 34% of toxicities were grade 1, 56% were grade 2, and the remaining 10% were grade 3.

Four of 15 subjects were unable to complete the treatment regimen, having withdrawn due to progression of visceral disease.

The rationale for the imiquimod plus nanoparticle albumin-bound (nab) paclitaxel (Abraxane) therapy derives from previous evidence that imiquimod, a toll-like receptor-7 agonist, has shown clinical efficacy against cutaneous metastases. Imiquimod stimulates secretion of Th1 cytokines and upregulates immune costimulatory molecules at the tumor site. Tumor-specific T cell immunity and tumor growth inhibition are enhanced. Moreover, paclitaxel has been shown to increase serum interferon-gamma levels and boost natural killer cell activity. Thus, the working hypothesis was that nab-paclitaxel would augment imiquimod’s antitumor effects, according to Dr. Salazar.

She and her coinvestigators examined the combination therapy’s impact upon endogenous tumor-specific immunity. They obtained pre- and posttreatment 2-mm skin biopsies from target lesions and were able to demonstrate that the treatment marginally enhanced endogenous immunity to the well-known breast cancer antigens HER2, p53, melanoma-associated antigen 3 (MAGE-3), insulin growth factor binding protein-2 (IGFBP-2), and topoisomerase IIa (TOPO-IIa).

The study was funded by a grant from the National Cancer Institute. Dr. Salazar declared having no relevant financial interests.

Recommended Reading

Breast Cancer Linked to Benign Thyroid Disease
Breast Cancer ICYMI
Meta-Analysis: Pregnancy-Associated Breast Cancer Fares Poorly
Breast Cancer ICYMI
Recent Diabetes Increases Breast Cancer Risk
Breast Cancer ICYMI
Acupuncture Flops as Relief for Muscle Pain From Aromatase Inhibitors
Breast Cancer ICYMI
Oncotype DX Cost Effective, Challenges Breast Cancer Practice
Breast Cancer ICYMI
Vitamin D Deficiency/Breast Cancer Link Questioned
Breast Cancer ICYMI
Metastatic Work-Up Not Needed for All N2/N3 Breast Cancers
Breast Cancer ICYMI
T-DM1 Supports QOL in HER2+ Metastatic Breast Cancer
Breast Cancer ICYMI
Doctors, Patients Disconnected on Aromatase Inhibitor Compliance
Breast Cancer ICYMI
Fulvestrant Adds Punch to Anastrozole for HR+ Breast Cancer
Breast Cancer ICYMI