- Phase I trial of piritrexim capsules using prolonged, low-dose oral administration for the treatment of advanced malignancies. Feun, L.G., Savaraj, N., Benedetto, P., Hanlon, J., Sridhar, K.S., Collier, M., Richman, S., Liao, S.H., Clendeninn, N.J. J. Natl. Cancer Inst. (1991)