Patients will be treated four (4) cycles of combination cabozantinib with Lu-177 DOTATATE followed by maintenance cabozantinib. Cycles 1-4 combination cabozantinib with Lu-177 DOTATATE is given in 8-week cycles, with cabozantinib initiated on day 1 and Lu-177 DOTATATE given on day 14. Cabozantinib dosing is escalated during cycles 1-4 in the following manner: dose cohort 1 patients receive cabozantinib 20 mg daily, cohort 2 receive 40mg qod alternating with 20 mg qod, cohort 3 receive 40 mg qd, dose cohort 4 receive 60 mg qod alternating with 40 mg qod, and dose cohort 5 receive 60 mg qd. In all cohorts, during cycle 5 and beyond, single-agent maintenance cabozantinib is given in 4-week cycles in a qd dosing scheduling as follows: 20 mg qd cohort 1; 40 mg qd cohort 2; 40 mg qd cohort 3; 60 mg qd cohort 4; 60 mg qd cohort 5, until disease progression.
The phase I objective of this study is to establish the maximal tolerated dose (MTD) of cabozantinib in 20 mg, 40 mg and 60 mg dose escalation cohorts in combination with Lu-177 dotatate at a standard dose of 7.4 GBq in four (4) 8-week cycles followed by continuation cabozantinib.