Dendritic Cell Vaccine Before Surgery Promising in HER2+ Breast Cancer

At the American Society of Clinical Oncology (ASCO) annual meeting, researchers reported on a phase I/II neoadjuvant study that explored the efficacy and immune stimulation effects of an initial 6 weeks of immunotherapy using conventional dendritic cell intratumoral therapy plus trastuzumab (Herceptin) and pertuzumab (Perjeta), followed by 12 weeks of paclitaxel, trastuzumab, and pertuzumab.

In this exclusive MedPage Today video, lead author Hyo S. Han, MD, of the Moffitt Cancer Center Department of Breast Oncology in Tampa, Florida, explained the NATASHA study and what will be the next step.

Following is a transcript of her remarks:

Optimizing neoadjuvant therapy with improved toxicity is very important for patients with early-stage breast cancer, as we’ve been working on escalating therapy that led to more toxicity.

So in this study, in the NATASHA study, we thought to evaluate the addition of immunotherapy using intratumoral HER2-positive dendritic cell vaccine in addition to deescalated chemotherapy to see if it can lead to improved tumor control measured by pathologic complete response rate. We accrued the patient with early-stage HER2-positive breast cancer and patients who were treated with weekly intratumoral dendritic cell vaccines.

So first 6 weeks, patient essentially was given only immunotherapy with the vaccine plus trastuzumab and pertuzumab, and once the immunotherapy portion is completed, patient did receive weekly paclitaxel times 12, along with trastuzumab and pertuzumab and went on their standard-of-care breast surgery.

So we have reported 12 patients safety lead-in in this phase II study. Six patients were treated with 50 million dendritic cell vaccine dose and an additional six patients were treated with 100 million dendritic cell vaccines. And we did not see any new safety signals in either dose. And we have seen a great tumor control measured by breast MRI in this patient population.

So we have done breast MRI at baseline and following 6 weeks therapy and at the end of 18 weeks therapy that included chemotherapy portion. And we have seen great tumor control even for 6 weeks of immunotherapy, with the three patients showing complete tumor response, with eight patients with radiological partial response, and one patient with stable disease. And 11 out of 12 patients so far underwent breast surgery, and seven out of 11 patients had complete pathologic response, which is remarkable.

And this clinical trial is continuing to enroll to phase II portion. We decided to expand 100 million dendritic cell level, because when we analyzed the blood biomarkers, we have seen increased tumor immune cell trafficking to tumor cells with a higher dose level. So that’s why we decide to expand 100 million dendritic cell dose level.

Based on great response, although a very small sample size of 12 patients, but intratumoral dendritic cell vaccine seems to be very effective in terms of tumor control along with HER2-targeted therapy. And again, increased tumor cell trafficking from the peripheral anti-HER-2 CD4 Th1 [T-helper 1] cells have been remarkable so far in this small study.

So we continue to analyze those blood and tissue biomarkers to see how this immunotherapy is working in our patients in this neoadjuvant study.

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