Chemotherapy is a brutal but often life-saving treatment for an even worse disease. It can also reduce a patient's white blood cell count which hinders the body's ability to fight off infections, so injections of Neulasta (pegfilgrastim) are given the day after to help boost production. And to ensure those injections are given a full 27 hours after chemotherapy, this sticker, applied after treatment, automatically injects the necessary dosage exactly when needed.
The side effects of chemotherapy are notoriously unpleasant, and having to immediately return to a doctor's office for a shot while a patient is trying to recover isn't easy. So Amgen, the company who manufactures Neulasta, created this stick-on injector that allows chemotherapy patients to automatically receive the necessary injection while they're comfortably recovering at home. It also means there are less patients filling a clinic's waiting room who are just there for a simple shot.
The Neulasta injector does need to be applied to a patient by a medical professional. It uses a small needle inserted under the skin for the medication to be properly delivered -- it's not just a sticker. But it can be applied and prepped while a patient is still at the clinic receiving their chemotherapy. After the injection it can presumably be easily removed by the patient, or their caregiver, without the need for further medical intervention. So it saves them from having to make the trip to a doctor while they're feeling awful, which helps make the treatment slightly more bearable.