What's the type for the brand herceptin with an approval date of before 2006?
CREATE TABLE "cancer_immunotherapy_monoclonal_antibodi" (
  "antibody" text,
  "brand_name" text,
  "approval_date" real,
  "type" text,
  "target" text
);
SELECT "type" FROM "cancer_immunotherapy_monoclonal_antibodi" WHERE "approval_date"<2006 AND "brand_name"='herceptin';