TBCRC 039: a phase II study of preoperative ruxolitinib with or without paclitaxel for triple-negative inflammatory breast cancer

BACKGROUND

Patients with inflammatory breast cancer (IBC) have overall poor clinical outcomes, with triple-negative IBC (TN-IBC) being associated with the worst survival, warranting the investigation of novel therapies. Preclinical studies implied that ruxolitinib (RUX), a JAK1/2 inhibitor, may be an effective therapy for TN-IBC.

METHODS

We conducted a randomized phase II study with nested window-of-opportunity in TN-IBC. Treatment-naïve patients received a 7-day run-in of RUX alone or RUX plus paclitaxel (PAC). After the run-in, those who received RUX alone proceeded to neoadjuvant therapy with either RUX + PAC or PAC alone for 12 weeks; those who had received RUX + PAC continued treatment for 12 weeks. All patients subsequently received 4 cycles of doxorubicin plus cyclophosphamide prior to surgery. Research tumor biopsies were performed at baseline (pre-run-in) and after run-in therapy. Tumors were evaluated for phosphorylated STAT3 (pSTAT3) by immunostaining, and a subset was also analyzed by RNA-seq. The primary endpoint was the percent of pSTAT3-positive pre-run-in tumors that became pSTAT3-negative. Secondary endpoints included pathologic complete response (pCR).

RESULTS

Overall, 23 patients were enrolled, of whom 21 completed preoperative therapy. Two patients achieved pCR (8.7%). pSTAT3 and IL-6/JAK/STAT3 signaling decreased in post-run-in biopsies of RUX-treated samples, while sustained treatment with RUX + PAC upregulated IL-6/JAK/STAT3 signaling compared to RUX alone. Both treatments decreased GZMB+ T cells implying immune suppression. RUX alone effectively inhibited JAK/STAT3 signaling but its combination with PAC led to incomplete inhibition. The immune suppressive effects of RUX alone and in combination may negate its growth inhibitory effects on cancer cells.

CONCLUSION

In summary, the use of RUX in TN-IBC was associated with a decrease in pSTAT3 levels despite lack of clinical benefit. Cancer cell-specific-targeting of JAK2/STAT3 or combinations with immunotherapy may be required for further evaluation of JAK2/STAT3 signaling as a cancer therapeutic target.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov , NCT02876302. Registered 23 August 2016.

Neoadjuvant Chemotherapy and Endocrine Therapy for Older Patients with Estrogen Receptor Positive Breast Cancer: Comparison of Approaches

BACKGROUND

Benefits of a pathologic complete response (pCR) following neoadjuvant therapy are well established, yet outcomes for older women are understudied. We sought to examine the pCR and overall survival (OS) rates of women with estrogen receptor (ER) positive breast cancer across age groups.

METHODS

Women diagnosed with cT1-4, N0-3, M0, ER+/HER2- breast cancer (2010-2018) who underwent neoadjuvant chemotherapy (NACT) or neoadjuvant endocrine therapy (NET) followed by surgery were selected from the National Cancer Database and categorized by age. Differences were tested, and Cox proportional hazards models were used to estimate the association of response with OS after adjustment for covariates.

RESULTS

In the 43,009-patient cohort, 84.8% received NACT and 15.2% received NET. Of those aged ≥ 70 (N = 5623), 51.0% received NACT, and 49.0% received NET. Compared with younger women receiving NACT, older women were less likely to have a breast or nodal pCR [no pCR by age: 85.1% (≥ 70 years) vs 82.2% (50-69 years) vs 77.7% (< 50 years), p < 0.001]. Rates of pCR were similarly low for all women receiving NET [no pCR by age: 95.6% (≥ 70 years) vs 95% (50-69 years) vs 96% (< 50 years), p = 0.06]. After adjustment, pCR after NACT was not associated with OS for older patients, but better survival outcomes were noted for older patients achieving pCR after NET.

CONCLUSION

For women with ER+/HER2- breast cancer, pCR rates after NACT are lower in older women compared with younger women, and are equally low after NET for all women. However, pCR after NET is associated with improved OS among older women, unlike pCR after NACT.

Abstract 192: A novel and rapid patient-derived organoid breast cancer platform for precision medicine

An increasing number of studies performing correlative drug screens on patient-derived organoids (PDO) are revealing enormous potential for these models in predicting patient response to therapy. Despite this, their future use in a clinical setting is hindered by intrinsic limitations of PDO models, namely low success rates in establishing growing cell cultures from tumor tissue samples and long return times for drug response data that fall outside timescales of clinical actionability. To address these limitations, we leveraged technological advances in emulsion-based microfluidics and droplet generators to develop MicroOrganoSpheres (MOS) - microscale environments containing tumorspheres that retain structural, cellular, and genetic properties of an individual patient’s diseased tissue. Here, we focused on generating MOS from breast cancer tissue biopsies and resections across different subtypes of breast cancer. We established over 30 unique patients’ breast MOS samples at an average of 80% success, with the majority of these samples being hormone receptor positive (ER+/PR+) - the most clinically lethal and challenging subtype to establish. We evaluated MOS dose-responses across several first line standard of care chemotherapies for breast cancer. For this, we created a semi-automated workflow paired with high-content imaging for quantifying dose responses and tracking longitudinal cell dynamics during dosing. We generated dose response data for MOS samples, being able to move from primary tissue samples to MOS to drug dosing data within a clinically relevant timescale of 2-3 weeks. We conclude that our platform demonstrates the feasibility of 1) efficiently establishing MOS from breast cancer patient tumor samples from different subtypes and 2) performing drug dosing studies on these samples with improved turnaround times that enable clinical actionability for the patient. Together, these findings provide a foundation for evaluating this technology as a diagnostic tool in future clinical settings.

Citation Format: David M. Graham, Gabrielle Rupprecht, Eric D. Bankaitis, Jeremy M. Force, Wylie Watlington, Steven W. Metzger, Xiling Shen, David Hsu. A novel and rapid patient-derived organoid breast cancer platform for precision medicine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 192.