Pathophysiology
The brain itself is not sensitive to pain, because it lacks pain receptors. However, several areas of the head and neck do have pain receptors and can thus sense pain. These include the extracranial arteries, middle meningeal artery, large veins, venous sinuses, cranial and spinal nerves, head and neck muscles, the meninges, falx cerebri, parts of the brainstem, eyes, ears, teeth, and lining of the mouth. Pial arteries, rather than pial veins are responsible for pain production.Headaches often result from traction to or irritation of the meninges and blood vessels. The pain receptors may be stimulated by head trauma or tumors and cause headaches. Blood vessel spasms, dilated blood vessels, inflammation or infection of meninges and muscular tension can also stimulate pain receptors. Once stimulated, a nociceptor sends a message up the length of the nerve fiber to the nerve cells in the brain, signalling that a part of the body hurts.Primary headaches are more difficult to understand than secondary headaches. The exact mechanisms which cause migraines, tension headaches and cluster headaches are not known. There have been different hypotheses over time that attempt to explain what happens in the brain to cause these headaches.Migraines are currently thought to be caused by dysfunction of the nerves in the brain. Previously, migraines were thought to be caused by a primary problem with the blood vessels in the brain.
The median time to response in participants was 2.0 months (range, 1.6 to 13.5), the median duration of response was 7.7 months (95% confidence interval [CI], 4.9 to 10.8), the median progression free survival was 5.5 months, and the median overall survival was 13.0 months. Of the participants that achieved an objective response to sacituzumab govitecan-hziy, 55.6% maintained their response for six or more months and 16.7% maintained their response for twelve or more months.Sacituzumab govitecan-hziy was granted accelerated approval along with priority review, breakthrough therapy, and fast track designations. The U.S. Food and Drug Administration (FDA) granted approval of Trodelvy to Immunomedics, Inc.In April 2021, the FDA granted regular approval to sacituzumab govitecan for people with unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC) who have received two or more prior systemic therapies, at least one of them for metastatic disease. Efficacy and safety were evaluated in a multicenter, open-label, randomized trial (ASCENT; NCT02574455) conducted in 529 participants with unresectable locally advanced or mTNBC who had relapsed after at least two prior chemotherapies, one of which could be in the neoadjuvant or adjuvant setting, if progression occurred within twelve months.