Systematic analysis of early phase clinical studies for patients with breast cancer: Inclusion of patients with brain metastasis

PURPOSE

This systematic review aims to better define the limitations and patterns with which patients with MBC and CNS metastasis are enrolled into early phase developmental therapeutics trials.

METHODS

In June 2016, PubMed search was conducted using the following keywords: "Breast cancer". Drug-development phase 1, phase 2 or phase 1/2 trials for patients with MBC were included. Multiple-histology trials and trials without an efficacy endpoint were excluded.

RESULTS

In total, 1474 studies were included; Inclusion criteria for 423 (29%) allowed for CNS metastasis, 770 (52%) either excluded or did not document eligibility of patients with CNS disease. Trials accruing patients with HER2-positive MBC and including targeted therapies had higher odds of allowing for patients with CNS disease (adjusted OR 1.56, 95% CI 1.08-2.2.6; p=0.019 and 1.49, 95% 1.08-2.06; p=0.014, respectively). There were also higher odds of accrual of patients with CNS involvement into clinical trials over time (odds ratio=1.10, 95% CI 1.07-1.12; p<0.0001).

CONCLUSION

Most published early phase clinical trials either did not clearly document or did not allow for accrual of patients with CNS disease. Early phase trials with targeted agents or enrolling HER2+ MBC had higher odds of permitting CNS metastases.

Developmental therapeutics for patients with breast cancer and central nervous system metastasis: current landscape and future perspectives

Breast cancer is the second-leading cause of metastatic disease in the central nervous system (CNS). Recent advances in the biological understanding of breast cancer have facilitated an unprecedented increase of survival in a subset of patients presenting with metastatic breast cancer. Patients with HER2 positive (HER2+) or triple negative breast cancer are at highest risk of developing CNS metastasis, and typically experience a poor prognosis despite treatment with local and systemic therapies. Among the obstacles ahead in the realm of developmental therapeutics for breast cancer CNS metastasis is the improvement of our knowledge on its biological nuances and on the interaction of the blood–brain barrier with new compounds. This article reviews recent discoveries related to the underlying biology of breast cancer brain metastases, clinical progress to date and suggests rational approaches for investigational therapies.

Abstract P6-17-04: A phase II, open-label, multi-center study of ANG1005, a novel brain-penetrant taxane derivative, in breast cancer patients with recurrent CNS metastases

Background: Treatment options for brain metastases are limited to local therapies due to the inability of most anti-cancer agents to cross the blood brain barrier (BBB). ANG1005 is a novel taxane derivative, being developed for targeted treatment of brain metastases. It consists of 3 paclitaxel molecules covalently linked to Angiopep-2 designed to cross the BBB and to penetrate malignant cells, regardless of location, via the low density lipoprotein (LDL) receptor related protein-1 (LRP-1) transport system.

Methods: Adult patients with measurable recurrent brain metastases from breast cancer with, or without, leptomeningeal disease are currently being enrolled in this multi-center, open-label study (planned n=56). ANG1005 is administered IV at 600 mg/m2 every three weeks (one cycle) until disease progression, unacceptable toxicity or consent withdrawal. HER2+ patients are allowed to continue HER2 targeted therapies. The primary endpoint is intracranial objective response rate, as assessed by MRI using CNS RECIST 1.1. Secondary endpoints include duration of intracranial response, median progression-free survival, 3/6/12-month progression-free survival rate, overall survival at 6 months, extracranial objective response rate, safety and tolerability. Extracranial response is also assessed by CT using RECIST 1.1. An imaging sub-study, evaluating the use of 18F-FLT-PET in comparison to MRI, is also ongoing in 10 patients with measurable brain metastases from breast cancer, receiving ANG1005 IV at 550 mg/m2.

Results: Accrual is ongoing and to date, 48 patients have been treated with a range of 1-18 cycles of ANG1005. Median age is 47 years (range: 26-65). Safety profile is similar to that of paclitaxel with myelosuppression as the predominating toxicity. Based on data from patients evaluated to date for intracranial response, 6/30 (20%) patients had a partial response (PR) and 17/30 (57%) had a stable disease (SD), as best response. A sub-analysis, based on breast cancer sub-type is presented below:

Intracranial Response by Breast Cancer SubsetOutcome by CNS RECISTHER2- (n=13)HER2+ (n=17)TNBC (n=6)LMD (n=11)PR, n (%)1 (8%)5 (29%)1 (17%)4 (36%)SD, n (%)6 (46%)10 (59%)2 (33%)5 (45%)PD, n (%)6 (46%)2 (12%)3 (50%)2 (18%)TNBC, triple-negative breast cancer, a sub-group of HER2-; LMD, leptomeningeal disease, including 3 HER2- and 8 HER2+ patients

The longest duration on treatment is for 18 cycles, seen in a patient with an intracranial PR that sustained for 10 cycles; the treatment is still ongoing.

Extracranial tumor evaluations were completed in 14 patients, all showing disease control including in those previously treated with paclitaxel. One (7%) patient had a PR and 13 (93%) patients had an SD.

Conclusions: CNS activity was observed in all subsets of breast cancer, suggesting that ANG1005 is a promising therapy for treatment of brain and leptomeningeal metastases from breast cancer. ANG1005 treatment also resulted in disease control in extracranial lesions, including patients previously treated with paclitaxel. The dose and treatment regimen were well tolerated with a safety profile similar to paclitaxel. Updated efficacy and safety data will be presented at the meeting.

Citation Format: Tang S-C, Bates S, Kesari S, Brenner AJ, Anders CK, Garcia A, Ibrahim NK, Tkaczuk KHR, Kumthekar P. A phase II, open-label, multi-center study of ANG1005, a novel brain-penetrant taxane derivative, in breast cancer patients with recurrent CNS metastases. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-17-04.

Molecular characterization of avian paramyxovirus 1 isolates collected from cormorants in Canada from 1995 to 2000

Sequences encompassing cleavage sites of fusion protein genes were obtained for avian paramyxovirus 1 isolates from cormorants in Canada. All isolates have the virulent cleavage site SRGRRQKR*FVG. They form a distinct cluster within isolates obtained around the world and may represent a novel genotype closely related to genotype V.