Cohorts of 3-6 patients receive escalating doses of motexafin gadolinium until the MTD is determined. The first cohort receives motexafin gadolinium 5 days a week for 3 weeks; the second cohort receives motexafin gadolinium 3 days a week for 6 weeks; and subsequent cohorts receive motexafin gadolinium 5 days a week for 6 weeks. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity.