Arm 1 patients will receive MPDL3280A (Atezolizumab) for 24 cycles. After completion of treatment, patients will be followed up 3 monthly until progression or for 2 years post the end of treatment.
Arm 2/Arm 3 patients will receive Vemurafenib (Arm 2) or Alectinib (Arm 3) twice a day until disease progression. For administrative purposes treatment is divided into 28 day cycles. Patients will be seen monthly.
Arm 4 patients will receive Trastuzumab Entamsine on day 1 of a 21 day cycle, and should be treated until disease progression.
For TRACERx patients, follow up will then continue under the TRACERx protocol for as long as TRACERx remains open. For non-TRACERx patients or where TRACERx is closed, patients will revert to routine follow up.