Hi Lee MAc and gile , I did it work so, thanks both.
(defun C:CAUCE (/
;;; pt1 pt2 distancia
)
(setvar "cmdecho" 1)
(setvar 'OSMODE 1)
(setq DISTANCIA 0)
(setq PT1 (getpoint "\nInicio: "))
(command "_.pline")
(command PT1)
(while (> (getvar "CMDACTIVE") 0)
(setq PT2 (getvar 'LASTPOINT))
(setq DIST (distance PT1 PT2))
(setq PT1 PT2)
(setq DISTANCIA (+ DISTANCIA DIST))
(princ DISTANCIA)
(command PAUSE))
(command)
(setq TEXTO (strcat (rtos DISTANCIA 2 3) " Km"))
(setq PT2 (getvar 'LASTPOINT))
(command "_text" "_c" PT2 12 0 TEXTO)
)