Most clinical trials exclude patients with poor performance or comorbidities. To study whether patients with these characteristics can be treated within a clinical trial, we conducted a study for patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) with poor performance, organ dysfunction or comorbidities. Primary endpoint was 60-day survival. Study included stopping rules for survival and response. Treatment consisted on a combination of azacitidine and vorinostat. Thirty patients (16 with MDS, 14 with AML) were enrolled. Median follow-up was 7.4 months (0.3-29). Sixty-day survival was 83%. No stopping rules were met. Main adverse events (AEs) were grades 1 and 2 gastrointestinal toxicities. In view of these results, we expanded the study and treated 79 additional patients: 27 with azacitidine (AZA) and 52 with azacitidine and vorinostat (AZA+V). Median follow-up was 22.7 months (12.6-47.5). Sixty-day survival rate was 79% (AZA = 67%, AZA+V = 85%, P = 0.07). Median overall survival was 7.6 months (4.5-10.7). Median event-free survival was 4.5 months (3.5-5.6). Main AEs included grades 1 and 2 gastrointestinal toxicities. Our results suggest this subset of patients can be safely treated within clinical trials and derive clinical benefit. Relaxation of standard exclusion criteria may increase the pool of patients likely to benefit from therapy.