Vacco v. Quill
A group of doctors filed a lawsuit in federal court.  They argued that this law was unconstitutional.  They said the law violated the Equal Protection Clause of the Fourteenth Amendment to the Constitution.  The Equal Protection Clause says that every state must give everyone "the equal protection of the laws."  The doctors argued that because of the law against physician-assisted suicide, terminally ill people did not have equal rights under the law.  They pointed out that terminally ill patients could refuse treatment, which would lead to their death.  However, these same patients did not have the right to give a doctor permission to end their lives.  Basically, they were arguing that refusing treatment in order to cause death, and asking a doctor to help cause death, were the same thing.