Table 1.
Baseline Characteristics of the Patients.*
| Characteristic | Interleukin-2 Alone (N = 94) |
Vaccine–Interleukin-2 (N = 91) |
P Value |
|---|---|---|---|
| Sex — no. (%) | 0.53 | ||
| Male | 63 (67) | 57 (63) | |
| Female | 31 (33) | 34 (37) | |
| Mean age — yr | 50.3 | 46.9 | 0.04 |
| Race or ethnic group — no. (%)† | 1.00 | ||
| White | 91 (97) | 90 (99) | |
| Hispanic | 2 (2) | 1 (1) | |
| Other | 1 (1) | 0 | |
| ECOG performance status — no. (%)‡ | 0.92 | ||
| 0 | 78 (83) | 76 (84) | |
| 1 | 16 (17) | 15 (16) | |
| Site of disease — no. (%) | |||
| Cutaneous or subcutaneous only | 8 (9) | 8 (9) | 0.95 |
| Any other site | 86 (91) | 83 (91) | |
| Disease stage — no. (%)§ | 0.33 | ||
| Locally advanced III | 3 (3) | 5 (5) | |
| IV | 91 (97) | 83 (91) | |
| M1a | 25 (27) | 22 (24) | |
| M1b | 29 (31) | 32 (35) | |
| M1c | 37 (39) | 29 (32) | |
| Data missing | 0 | 3 (3) | |
| Previous treatment — no. (%) | |||
| Surgery | 86 (91) | 86 (95) | 0.42 |
| Interferon-alfa | 39 (41) | 50 (55) | 0.07 |
| Chemotherapy | 11 (12) | 11 (12) | 0.94 |
| Radiation | 14 (15) | 14 (15) | 0.93 |
| Low-dose interleukin-2 | 7 (7) | 11 (12) | 0.29 |
Interleukin-2 was administered in patients in both groups at a dose of 720,000 IU per kilogram of body weight every 8 hr. The vaccine administered in the vaccine–interleukin-2 group was a gp100:209–217(210 M) peptide vaccine (1 mg) plus incomplete Freund’s adjuvant (Montanide ISA-51). P values were calculated with the use of a Wilcoxon rank-sum test for skewed continuous variables and a chi-square test or Fisher’s exact test for categorical variables.
Race or ethnic group was determined by the study coordinators.
The Eastern Cooperative Oncology Group (ECOG) performance status ranges from 0 to 5, with higher scores indicating greater impairment (5 indicates death). ECOG 0 indicates that the patient is fully active, and ECOG 1 that a patient is restricted in the performance of physically strenuous activity but is ambulatory and able to carry out work of a light or sedentary nature.
The stage was determined according to the criteria of the American Joint Committee on Cancer, 6th edition, which are based on the sites of disease. (No measurements of lactate dehydrogenase levels were performed.)