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SummaryWe report the preclinical evaluation of PF-06463922, a potent and brain-penetrant ALK/ROS1 inhibitor. Compared with other clinically available ALK inhibitors, PF-06463922 displayed superior potency against all known clinically acquired ALK mutations, including the highly resistant G1202R mutant. Furthermore, PF-06463922 treatment led to regression of EML4-ALK-driven brain metastases, leading to prolonged mouse survival, in a superior manner. Finally, PF-06463922 demonstrated high selectivity and safety margins in a variety of preclinical studies. These results suggest that PF-06463922 will be highly effective for the treatment of patients with ALK-driven lung cancers, including those who relapsed on clinically available ALK inhibitors because of secondary ALK kinase domain mutations and/or brain metastases.

Although targeted therapies are often effective systemically, they fail to adequately control brain metastases. In preclinical models of breast cancer that faithfully recapitulate the disparate clinical responses in these micro-environments, we observed that brain metastases evade phosphatidylinositide 3-kinase (PI3K) inhibition despite drug accumulation in the brain lesions. In comparison to extracranial disease, we observed increased HER3 expression and phosphorylation in brain lesions. HER3 blockade overcame the resistance of HER2-amplified and/or PIK3CA-mutant breast cancer brain metastases to PI3K inhibitors, resulting in marked tumor growth delay and improvement in mouse survival. These data provide a mechanistic basis for therapeutic resistance in the brain microenvironment and identify translatable treatment strategies for HER2-amplified and/or PIK3CA-mutant breast cancer brain metastases.

Brain metastases represent a devastating progression of luminal breast cancer. While targeted therapies are often effective systemically, they fail to adequately control brain metastases. In preclinical models that faithfully recapitulate the disparate clinical responses in these microenvironments, we observed that brain metastases evade PI3K inhibition despite efficient drug delivery. In comparison to extracranial disease, there is increased HER3 expression and phosphorylation in the brain lesions. HER3 blockade overcomes the resistance of both HER2-amplified and/or PIK3CA-mutant breast cancer brain metastases to PI3K inhibitors, leading to striking tumor growth delay and significant improvement of mouse survival. Collectively, these data provide a mechanistic basis underlying therapeutic resistance in the brain microenvironment and identify rapidly translatable treatment strategiesfor HER2-amplified and/or PIK3CA-mutant breast cancer brain metastases. Citation Format: Gino B. Ferraro, David P. Kodack, Vasileios Askoxylakis, Qing Sheng, Mark Badeaux, Shom Goel, Xiaolong Qi, Ram Shankaraiah, Alexander Z. Cao, Rakesh R. Ramjiawan, Divya Bezwada, Bhushankumar Patel, Youngchul Song, Carlotta Costa, Kamila Naxerova, Christina Wong, Jonas Kloepper, Rita Das, Angela Tam, Jantima Tanboon, Dan G. Duda, Ryan C. Miller, Marni B. Siegel, Carey K. Anders, Melinda Sanders, Valeria M. Estrada, Robert Schlegel, Carlos L. Arteaga, Elena Brachtel, Alan Huang, Dai Fukumura, Jeffrey A. Engelman, Rakesh K. Jain. The brain microenvironment mediates resistance in luminal breast cancer to PI3K inhibition through HER3 activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5008. doi:10.1158/1538-7445.AM2017-5008

Carvacrol, a monoterpene phenol, is known to be present in the volatile oils of Thymus vulgaris, Carum copticum and Origanum vulgare, and has been shown to have anti-proliferative effects on variou...

Overcoming resistance to targeted kinase inhibitors is a major clinical challenge in oncology. For 1st and 2nd generation ALK inhibitors acquired resistance due to ALK kinase domain mutations and/or pharmacological drug resistance are major causes for disease relapse. Here, we report the preclinical evaluation of PF-06463922, a potent and brain penetrant ALK/ROS1 inhibitor with sub to low nanomolar cell potency against ALK fusions and all known clinically-acquired resistant mutations. PF-06463922 exhibited marked cytoreductive activity in tumor xenografts driven by various ALK mutants. Furthermore, PF-06463922 led to significant regression of EML4-ALK driven lung cancer brain metastasis and prolonged mouse survival. Compared to other clinically available ALK inhibitors, PF-06463922 is unique in its superior potency against a broad spectrum of acquired ALK mutations, including the highly resistant G1202R mutant and its robust antitumor activity in the brain. Furthermore, PF-06463922 demonstrated remarkable selectivity and safety margins in a variety of preclinical studies. These results suggest that PF-06463922 may be highly effective for the treatment of patients with ALK-driven lung cancers, including those who relapsed on clinically available ALK inhibitors due to ALK secondary mutations and/or brain metastases. Citation Format: Luc Friboulet, Helen Zou, David P. Kodack, Lars D. Engstrom, Qiuhua Li, Melissa West, Ruth W. Tang, Hui Wang, Konstantinos Tsaparikos, Jinwei Wang, Sergei Timofeevski, Dac M. Dinh, Hieu Lam, Justine L. Lam, Shinji Yamazaki, Wenyue Hu, Bhushankumar Patel, Divya Bezwada, Sidra Mahmood, Eugene Lifshits, Timothy Affolter, Patrick B. Lappin, Hovhannes Gukasyan, Nathan Lee, Shibing Deng, Rakesh K. Jain, Ted W. Johnson, Alice T. Shaw, Valeria R. Fantin, Tod Smeal. PF-06463922, a novel next generation ALK/ROS1 inhibitor, overcomes resistance to 1st and 2nd generation ALK inhibitors in pre-clinical models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 130. doi:10.1158/1538-7445.AM2015-130