N- [4- (2,4-Difluorophenoxy) -3- (6-methyl-7-oxo-6,7-dihydro-1 H -pyrrole [2,3-c] pyridin-4-yl) phenyl] ethanesulfonamide and crystalline forms thereof as a pharmaceutical ingredient suitable for pharmaceutical compositions useful in the treatment of diseases, for example, cancer. Claim 2: An isolated crystalline form of N- [4- (2,4-difluorophenoxy) -3- (6-methyl-7-oxo-6,7-dihydro-1H-pyrrole [2,3-c] pyridine- 4-yl) phenyl] ethanesulfonamide, characterized in that the crystalline form has a powder X-ray diffraction pattern comprising the following peak values 2q ± 0.2: 6.2 °,9,11,12.3%12.6%$13.114.1%15.6%16.4%16.5 degrees16.9 degrees17.8 degrees18.1%18.3%18.9 degrees20.4 degrees21.1%21.6%21.8 degrees22.1%22.9 degrees23.2%24.4 degrees24.7 degrees25.6%26.3%27 and 27.3N-[4-(2,4-difluorofenoxi)-3-(6-metil-7-oxo-6,7-dihidro-1H-pirrol[2,3-c]piridin-4-il)fenil]etansulfonamida y formas cristalinas de la misma como ingrediente farmacéutico adecuado para composiciones farmacéuticas de utilidad en el tratamiento de enfermedades, por ejemplo, cáncer. Reivindicación 2: Una forma cristalina aislada de N-[4-(2,4-difluorofenoxi)-3-(6-metil-7-oxo-6,7-dihidro-1H-pirrol[2,3-c]piridin-4-il)fenil]etansulfonamida, caracterizada porque la forma cristalina tiene un patrón de difracción de rayos X en polvo que comprende los siguientes valores pico 2q ± 0,2: 6,2º, 9,0º, 11,0º, 12,3º, 12,6º, 13,1º, 14,1º, 15,6º, 16,4º, 16,5º, 16,9º, 17,8º, 18,1º, 18,3º, 18,9º, 20,4º, 21,1º, 21,6º, 21,8º, 22,1º, 22,9º, 23,2º, 24,4º, 24,7º, 25,6º, 26,3º, 27,0º y 27,3º.
