This clinical study is looking at whether a drug called crizotinib, which is used in some patients with lung cancer, is effective in a sub-type of breast cancer, called lobular breast cancer. As the majority of lobular breast cancers are oestrogen receptor positive (ER+ve), crizotinib will be combined with a second drug, fulvestrant, to try to block tumour growth that is driven by oestrogen.~Crizotinib targets cancers with genetic changes in two genes called ALK and ROS1. Lung cancers with changes in these genes usually get smaller when treated with crizotinib. Laboratory work at the Institute of Cancer Research has shown that lobular breast cancer cells, due to a mutation in a different gene called CDH1, appear to be similarly affected by crizotinib.~Fulvestrant is an oestrogen receptor down regulator and blocks the effects of oestrogen on oestrogen receptor positive (ER+ve) breast cancer cells. Fulvestrant is an established and approved anti-hormone therapy which patients with breast cancers are receiving in the clinic. It is possible that the combination of crizotinib and an anti-oestrogen agent will shrink the tumour(s) more effectively and prevent further growth. Because fulvestrant is only effective in post-menopausal women, if participants have not yet gone through the menopause, participants will need to start (or continue to receive) a monthly injection under the skin to temporarily stop the function of the participants ovaries to be eligible to take part in the trial.~This injection is called goserelin and has to be started at least 4 weeks before the first day of treatment on the trial.~The overall aims of this clinical study are to find out:~The proportion of patients whose tumour(s) shrink when they are treated with crizotinib and fulvestrant~The safety and tolerability of fulvestrant in combination with crizotinib, to determine that they can be given together without unacceptable side effects~What the drugs do to the tumours, which will help us decide which patients may benefit from this combination in the future
The purpose of this study is to find out how effective the combination of crizotinib and fulvestrant is in shrinking lobular breast cancer tumours. The investigators will also be assessing the side effects of the combination of crizotinib tablets and fulvestrant injections. The side effects and the doses of crizotinib and fulvestrant have already been evaluated in large clinical trials, but this is the first time these two drugs will be combined together.