Sequential studies of melanoma leukocyte-dependent antibody activity in melanoma patients

Adjuvant immunotherapy of patients with high-risk melanoma using vaccinia viral lysates of melanoma: results of a randomized trial

PURPOSE

Patients with high-risk melanoma treated by immunotherapy with vaccinia viral lysates were found in phase II studies to have improved survival compared with historical controls. We therefore elected to test this therapy in a phase III study.

PATIENTS AND METHODS

A prospective, randomized, multicenter trial to determine whether immunotherapy with a vaccine prepared from vaccinia melanoma cell lysates (VMCL) over a 2-year period after definitive surgery would improve relapse-free survival (RFS) and overall survival (OS) in patients with American Joint Committee on Cancer stage IIB and III melanoma compared with a control group treated only with surgery.

RESULTS

A total of 700 patients were randomized: 353 to VMCL and 347 to no immunotherapy. Seventy-seven percent had lymph node (LN) metastases and 66% had clinically detected LN metastases. Analysis on the basis of all eligible, randomized patients (n = 675) found, after a median follow-up period of 8 years, a median OS of 88 months in the control versus 151 months in the treated group (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.64 to 1.02; P =.068 by stratified univariate Cox analysis). At 5 and 10 years, survival rates for control and treated patients were 54.8% v 60.6% and 41% v 53.4%, respectively. Median RFS was 43 months in the control group compared with 83 months in the treated group (HR, 0.86; 95% CI, 0.7 to 1.07; P =.17). RFS at 5 years was 50.9% for the treated group and 46.8% for the control group. There were no selective benefits from the vaccine for particular subsets of patients.

CONCLUSION

Immunotherapy with VMCL was not associated with a statistically significant improvement in OS or RFS, with CIs not ruling out important gains from such treatment.

Current status and future prospects for adjuvant therapy of melanoma

Advances in the treatment of melanoma have resulted mainly from improved surgical management of the primary tumour assisted by a greater appreciation of major prognostic factors in the natural history of the disease. Further improvement in the treatment of melanoma will depend largely on introduction of methods to prevent recurrence of the disease. The present review discusses criteria for selection of patients with a high risk of recurrent disease and the adjuvant treatment that has been used in past studies to prevent recurrences. With few exceptions various regimens of chemotherapy, non-specific immunotherapy with bacterial products or combinations of these treatments have not increased disease free or survival periods. Immunotherapy with various sources of melanoma antigens or with viral lysates of melanoma cells have produced encouraging results in uncontrolled studies and require further evaluation. Several advances appear to provide scope for new initiatives in immunotherapy. These include an appreciation of the role of suppressor cells in regulation of immune responses against tumour cells and possible methods to inhibit their activity. A second is the definition of various lymphokines involved in generation of immune responses (particularly interleukin 2) and development of in vitro methods for large scale production of these factors. Thirdly, methods are becoming available to define the heterogeneity of tumour cells in terms of cell surface antigens or their release of soluble factors which may help select treatments appropriate to each patient.

Immunity to melanoma associated antigens detected by both leukocyte adherence inhibition and antibody dependent cellular cytotoxicity assays

Two different assays, leukocyte adherence inhibition (LAI) and antibody dependent cellular cytotoxicity (ADCC) have been used to measure the immune responses of 69 melanoma patients, 116 patients with other tumours and 64 normal controls to a number of melanoma and control antigens. Using the LAI test, melanoma patients were significantly more reactive (43-69% positive) than normal controls (7-32% positive) to membrane extracts from 3 to 6 melanoma cell lines, and 4 to 6 extracts of melanoma biopsy specimens. However, the proportion of patients with other tumours reacting with 3 of these extracts was similar to melanoma patients. Melanoma patients were more reactive to the melanoma extract than to extracts of normal skin, normal muscle and 2 breast cancer cell lines. ADCC tests were used to detect anti-melanoma antibodies in patient sera. Preferential reactivity by melanoma patients was detected towards only 2 of the 6 melanoma cell lines tested--53% of 55 melanoma sera reactive to LiBr compared with 28% of 79 sera from patients with other tumours and 17% of 29 normal sera (P less than 0.05); 42% of 31 melanoma sera reactive to MM127 compared with 18% of 22 sera from other tumour patients (n.s.) and 5% of 20 normal sera (P less than 0.005). Melanoma patients tested against a number of melanoma cell lines by ADCC or antigen extracts by LAI generally reacted with one or more, but not all of them. Thus, incomplete cross-reactivity between different melanomas was observed. There was no correlation between results of the same patient in the 2 tests.

Suppressor cell activity in melanoma patients. I. Relation to tumor growth an immunoglobulin levels in vivo

The effect of tumor growth on the suppressor cell activity of melanoma patients was examined by measurement of immunoglobulin produced in vitro in pokeweed mitogen (PWM)-stimulated cultures of B and T lymphocytes. B and T cells were separated by sheep red blood cell rosetting and suppressor cell activity was assessed by comparison of immunoglobulins produced in cultures with irradiated T cells (2,000 rads) to that with unirradiated T cells. In the majority of patients with localized melanoma, radiosensitive suppressor T cells were detected and appeared to be an augmentation of a normal physiological state. In patients with Stage I and II melanoma, removal of the tumor resulted in a significant decrease in suppressor activity against IgA and IgM but not against IgG production. Similar sequential changes in suppressor cell activity against IgA and IgM but not against IgG production. Similar sequential changes in suppressor cell activity were not generally detected in patients who had surgery for skin graft after previous removal of the primary melanoma or in patients undergoing surgery for non-malignant conditions. Sequential studies on the levels of serum immunoglobulins showed an apparent trend for immunoglobulins to increase after surgery. Of particular importance, the decrease in in vitro suppressor cell activity against IgM and IgG production after tumor removal in individual patients was significantly associated with an increase in immunoglobulin levels in the serum of these patients. It is suggested that these findings may account in part for the absence of detectable antibody responses to melanoma antigens in many patients and for the generalized immunodeficiency in patients with disseminated melanoma.

Tumour-related changes in natural killer cell activity in melanoma patients. Influence of stage of disease, tumour thickness and age of patients

The influence of tumour growth on the natural killer (NK) activity of melanoma patients was examined by analysis of NK activity in 51Cr release assays before and at intervals after surgical removal of localized melanoma. In patients with Stage I and II melanoma, removal of the tumour was associated with changes in the level of NK activity which were not detected in patients who had surgery for skin graft after previous removal of the primary melanoma. The changes in NK activity after removal of melanoma were however different in patients with Stage I compared to Stage II melanoma. In the former, NK activity which appeared specifically directed toward melanoma cells was maximal 2-4 weeks after removal of the tumour and then decreased to normal levels. The NK activity after surgery was directly related to the thickness of the tumour. In patients with Stage II melanoma, NK activity did not increase but fell to low levels after removal of the tumour. The level of NK activity in these patients was not related to the thickness of their primary melanoma. In patients with Stage I and II melanoma the NK activity against melanoma cells showed a significant increase with age. The reason for the different sequence of changes in NK activity after removal of melanoma in the two patient groups is unknown. It is suggested however that the differences observed in patients with Stage II melanoma may reflect differences in the tumour or host response which contributed to the spread of the tumour to regional lymph nodes in these patients.