Abstract P1-19-03: A phase I trial of sorafenib with whole brain radiotherapy (WBRT) in breast cancer patients with brain metastases and a correlative study of FLT-PET brain imaging in patients receiving WBRT with or without sorafenib

Background: WBRT is a standard therapy for metastatic breast cancer (MBC) patients (pts) with brain metastases (BM), but disease progression in the brain is common. Sorafenib, a tyrosine kinase inhibitor with anti-VEGF activity, has demonstrated anti-tumor efficacy in MBC and radiosensitizing activity preclinically. [18F] 3'deoxy-3'-fluorothymidine (FLT) is a new PET tracer which correlates with cellular proliferation and may improve response assessment in the brain. Methods: A phase I trial of sorafenib with WBRT in MBC pts with BM was conducted using a 3+3 design. Sorafenib was given orally daily at the start of WBRT for a total of 21 days with 3 doses levels: 200mg, 400mg, and 600mg. The primary endpoints were to determine a maximum tolerated dose (MTD) and to evaluate safety and toxicity. The secondary endpoint was central nervous system progression-free survival (CNS-PFS). Macdonald Criteria were used for response assessment with serial MRI brain imaging. Key eligibility criteria include MBC with new or progressive ≥ 1cm BM, ECOG PS 0-2, non-escalating corticosteroid dose, and no other concurrent anti-tumor therapy except trastuzumab. In parallel, we conducted a correlative FLT-PET imaging study (baseline, 7-10 days (FU1), and 10-12 weeks (FU2) after the WBRT) to assess radiographic changes among pts receiving WBRT + sorafenib and in a separate WBRT only cohort. FLT standard uptake value (SUV) and kinetic parameter data were obtained. Results: 13 pts were treated in the dose escalation phase and evaluable for dose-limiting toxicity (DLT). The median age was 56 years (range: 43-77). There were 4 HER2 positive (31%) and 3 triple negative (23%) pts. 2 pts had prior stereotactic radiosurgery. DLTs were: Grade (G) 4 increased lipase at 200mg (1 pt) and G3 rash at 400mg (3 pts) level. MTD was determined to be 200mg. 10 pts were evaluable for response (at least 1 follow up brain imaging). The overall response rate was 70%: 4 complete responses (CR) + 3 partial responses. All 13 pts were evaluated for CNS PFS with a median follow up of 29.7 months (min 19.6, max 57.4mo). Median CNS-PFS was 8.2 months (95%CI: 3.4-31.8). Median OS was 15.4 months (95% CI: 3.4-NR). A total of 10 pts with WBRT and sorafenib and 5 pts with WBRT only were enrolled in the FLT-PET study: all 15 pts had baseline FLT PET, 14 with FU1, and 9 with FU2. 55 baseline lesions, 38 at FU1 and 15 at FU2 were observed and analyzed. All lesions with FLT uptake had MRI correlates. Decline in average SUVmax of ≥25% was seen in 9/10 (90%) of WBRT+sorafenib and 2/4(50%) of WBRT only pts at FU1. A complete disappearance of FLT uptake was noted in 1 pt at FU1 and 2 more pts at FU2. Conclusions: Concurrent WBRT with sorafenib appears safe at 200mg daily dose with a higher rate of CR compared to historical WBRT data. We are currently enrolling patients in the safety-expansion cohort. This combination should be considered for further efficacy evaluation. Additional analysis of FLT-PET as a complementary imaging modality to MRI is currently ongoing. Clinical trial registry: NCT01724606 and NCT01621906. Support: Bayer, Susan G Komen, ASCO Gianni Bonadonna Breast Cancer Award

Citation Format: Morikawa A, Jhaveri K, Grkovski M, Tang K, Humm JL, Holodny A, Beal K, Schoder H, Seidman AD. A phase I trial of sorafenib with whole brain radiotherapy (WBRT) in breast cancer patients with brain metastases and a correlative study of FLT-PET brain imaging in patients receiving WBRT with or without sorafenib [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 P1-19-03.

Abstract P6-10-05: A pilot study of radiation (RT) and CTLA4-mediated checkpoint blockade with tremelimumab for the treatment of breast cancer brain metastases (BCBM)

This abstract was withdrawn by the authors.

Diffusion and perfusion MRI to differentiate treatment-related changes including pseudoprogression from recurrent tumors in high-grade gliomas with histopathologic evidence

BACKGROUND AND PURPOSE

Treatment-related changes and recurrent tumors often have overlapping features on conventional MR imaging. The purpose of this study was to assess the utility of DWI and DSC perfusion imaging alone and in combination to differentiate treatment-related effects and recurrent high-grade gliomas.

MATERIALS AND METHODS

We retrospectively identified 68 consecutive patients with high-grade gliomas treated by surgical resection followed by radiation therapy and temozolomide, who then developed increasing enhancing mass lesions indeterminate for treatment-related changes versus recurrent tumor. All lesions were diagnosed by histopathology at repeat surgical resection. ROI analysis was performed of the enhancing lesion on the ADC and DSC maps. Measurements made by a 2D ROI of the enhancing lesion on a single slice were recorded as ADCLesion and rCBVLesion, and measurements made by the most abnormal small fixed diameter ROI as ADCROI and rCBVROI. Statistical analysis was performed with Wilcoxon rank sum tests with P = .05.

RESULTS

Ten of the 68 patients (14.7%) had treatment-related changes, while 58 patients (85.3%) had recurrent tumor only (n = 19) or recurrent tumor mixed with treatment effect (n = 39). DWI analysis showed higher ADCLesion in treatment-related changes than in recurrent tumor (P = .003). DSC analysis revealed lower relative cerebral blood volume (rCBV)Lesion and rCBVROI in treatment-related changes (P = .003 and P = .011, respectively). Subanalysis of patients with suspected pseudoprogression also revealed higher ADCLesion (P = .001) and lower rCBVLesion (P = .028) and rCBVROI (P = .032) in treatment-related changes. Applying a combined ADCLesion and rCBVLesion model did not outperform either the ADC or rCBV metric alone.

CONCLUSIONS

Treatment-related changes showed higher diffusion and lower perfusion than recurrent tumor. Similar correlations were found for patients with suspected pseudoprogression.

Abstract P6-11-02: Patient characteristics and outcomes for patients with HER2-overexpressing breast cancer with brain metastases undergoing radiation therapy in the pre- and post adjuvant trastuzumab era

Background: Trastuzumab (H) has improved outcomes for patients with HER2 overexpressing (HER2+) breast cancer (BC) and thus increased the at-risk period for development of brain metastases (BM). In this study we describe the characteristics and outcomes of patients with HER2+BCBM who underwent stereotactic radiosurgery (SRS) or whole brain radiation (WBRT) as initial BM treatment (tx) in the pre- and the post adjuvant (adj) H era at MSKCC.

Methods: 100 consecutive pts with HER2+ BCBM who received SRS or WBRT from January 2001 to December 2011 were identified. Clinical, pathologic and tx information were obtained by retrospective review. Pt characteristics at the time of BM diagnosis (dx) and their associations with time from BM to death were evaluated by Kaplan-Meier (KM) curves, log-rank tests, and Cox proportional hazard models.

Results: The median age at BM dx was 54 yrs (range 26-79). 31% and 69% of pts received SRS and WBRT respectively. After the BM dx, 97% continued to receive systemic tx consisting of chemotherapy and/or anti-HER2 tx. 97% of pts received H for MBC and 17% received H in the adj setting (all after 2005). Patient characteristics were compared between pre-adj H (2001-2005) and post-adj H (2006-2011) cohorts. The only significant differences noted between the cohorts in univariate analysis were extra-CNS disease control and use of anti-HER2 therapy after BM dx: pre-adj H era pts had a higher likelihood of extra-CNS disease control (79.5% vs. 52%, p = 0.004) at BM dx and less use of anti-HER2 tx after BM dx (70% vs. 87.5%. p = 0.05). For all pts, the median follow-up for survivors was 33.5 mos (range 18-103). There were 79 deaths. The median survival from BM dx was 19.4 mos (95%CI: 15.5, 26.6). KM curves and log-rank tests showed significantly better survival from BM for pts with higher KPS, single BM, extra-CNS disease control, lack of neurologic sx at BM dx, initial presentation without LMD, use of lapatinib (ever), SRS as initial RT, and use of any anti-HER2 tx after BM dx. Multivariate analysis showed that higher KPS [HR 0.21 (0.09,0.53)], extra-CNS disease control [HR 2.89 (1.67, 5.00)], single BM [HR 4.73 (2.11,10.60)], use of anti-HER2 tx after BM dx [HR 0.30 (0.17,0.53)], asymptomatic status at BM dx [HR 3.69 (1.69,8.07)] were associated with improved survival from BM. Lack of neurologic sx at BM dx was significantly associated with longer survival from BM even after adjustment for other potentially confounding prognostic factors.

Conclusion: These data are mostly consistent with prior reports regarding prognostic factors and inform contemporary clinical trial design. In pts with HER2+BCBM where the majority were subsequently exposed to anti-HER2 and other systemic tx, presence of neurologic sx at BM dx was significantly associated with worse survival after BM dx. Prospective evaluation of screening brain MRI allowing for earlier detection, leading to more careful monitoring or pre-emptive tx of asymptomatic BM may be warranted. The observation of better extra-CNS disease control at BM dx among pts in the pre- adj H era was unexpected, is hypothesis generating, and requires independent confirmation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-02.