A system for treating a brain tumor, comprising a pump comprising an outer layer, which outer layer comprises a plurality of micro-pores and an inner layer, which inner layer encloses a space, which space is a medication reservoir for storing Avastin or a mixture of medicating agents with Avastin, which pump is implantable into the brain of a patient, which pump is expandable into an expanded state and contractable into a contracted state, a sampling cavity defined between the outer layer and the inner layer of the pump, at least one drug ampoule fluidically coupled to the pump; and an amount of the pharmaceutically active agent Avastin contained in the at least one drug ampoule, wherein the inner layer further contains a plurality of injector spines tips of which are tapered, and which injector spines are long enough to penetrate the outer layer when the pump is in an expanded state, wherein the pump is a magnetically controlled pump, wherein the outer layer is an outer membrane and the inner layer is an inner membrane, wherein the inner membrane and the outer membrane are seamed together at a base and a head of the pump by a pump solenoid assembly and a pump head assembly respectively, wherein the pump head assembly comprises a delivery/sampling head configured to allow the supply of Avastin from the drug ampoule to the reservoir and the removal of cerebrospinal fluid from the sampling cavity and wherein the inner and outer membranes (107, 106) are flexible, wherein the outer membrane is less flexible than the inner membrane, wherein the pump is configured such that during contraction of the pump the inner membrane is pushed outward thus extending the injector spines past the outer membrane so that increased pressure created by the contracting pump pushes the Avastin out of the medication reservoir through the injector spines, and wherein the pump is configured such that during expansion of the pump, the inner membrane collapses and retracts the injector spines so that the pressure differential of the pump draws in cerebral fluid through the micro-pores of the outer layer into the sampling cavity. which pump is implantable into the brain of a patient, which pump is expandable into an expanded state and contractable into a contracted state, a sampling cavity defined between the outer layer and the inner layer of the pump, at least one drug ampoule fluidically coupled to the pump; and an amount of the pharmaceutically active agent Avastin contained in the at least one drug ampoule, wherein the inner layer further contains a plurality of injector spines tips of which are tapered, and which injector spines are long enough to penetrate the outer layer when the pump is in an expanded state, wherein the pump is a magnetically controlled pump, wherein the outer layer is an outer membrane and the inner layer is an inner membrane, wherein the inner membrane and the outer membrane are seamed together at a base and a head of the pump by a pump solenoid assembly and a pump head assembly respectively, wherein the pump head assembly comprises a delivery/sampling head configured to allow the supply of Avastin from the drug ampoule to the reservoir and the removal of cerebrospinal fluid from the sampling cavity and wherein the inner and outer membranes (107, 106) are flexible, wherein the outer membrane is less flexible than the inner membrane, wherein the pump is configured such that during contraction of the pump the inner membrane is pushed outward thus extending the injector spines past the outer membrane so that increased pressure created by the contracting pump pushes the Avastin out of the medication reservoir through the injector spines, and wherein the pump is configured such that during expansion of the pump, the inner membrane collapses and retracts the injector spines so that the pressure differential of the pump draws in cerebral fluid through the micro-pores of the outer layer into the sampling cavity.