Phase 1/2 dose-escalation study of a GM-CSF-secreting, allogeneic, cellular immunotherapy for metastatic hormone-refractory prostate cancer

BACKGROUND

This open-label, multicenter, dose-escalation study evaluated multiple dose levels of immunotherapy in patients with metastatic hormone-refractory prostate cancer (HRPC). The immunotherapy, based on the GVAX platform, consisted of 2 allogeneic prostate-carcinoma cell lines modified to secrete granulocyte-macrophage-colony-stimulating factor (GM-CSF).

METHODS

Dose levels ranged from 100 x 10(6) cells q28d x 6 to 500 x 10(6) cells prime/300 x 10(6) cells boost q14d x 11. Endpoints included safety, immunogenicity, overall survival, radiologic response, prostate-specific antigen (PSA) kinetics, and serum GM-CSF pharmacokinetics.

RESULTS

Eighty men, median age 69 years (range, 49-90 years), were treated. The most common adverse effect was injection-site erythema. Overall, the immunotherapy was well tolerated. A maximal tolerated dose was not established. The median survival time was 35.0 months in the high-dose group, 20.0 months in the mid-dose, group, and 23.1 months in the low-dose group. PSA stabilization occurred in 15 (19%) patients, and a >50% decline in PSA was seen in 1 patient. The proportion of patients who generated an antibody response to 1 or both cell lines increased with dose and included 10 of 23 (43%) in the low-dose group, 13 of 18 (72%) in the mid-dose group, and 16 of 18 (89%) in the high-dose group (P = .002; Cochran-Armitage trend test).

CONCLUSIONS

This immunotherapy was well tolerated. Immunogenicity and overall survival varied by dose. Two phase 3 trials in patients with metastatic HRPC are underway.

Granulocyte macrophage colony-stimulating factor--secreting allogeneic cellular immunotherapy for hormone-refractory prostate cancer

PURPOSE

This trial evaluated the safety, clinical activity, and immunogenicity of an allogeneic cellular immunotherapy in 55 chemotherapy-naïve patients with hormone-refractory prostate cancer (HRPC). The immunotherapy, based on the GVAX platform, is a combination of two prostate carcinoma cell lines modified with the granulocyte macrophage colony-stimulating factor (GM-CSF) gene.

EXPERIMENTAL DESIGN

HRPC patients with radiologic metastases (n = 34) or rising prostate-specific antigen (PSA) only (n = 21) received a prime dose of 500 million cells and 12 boost doses of either 100 million cells (low dose) or 300 million cells (high dose) biweekly for 6 months. End points were changes in PSA, time to progression, and survival.

RESULTS

Median survival was 26.2 months (95% confidence interval, 17, 36) in the radiologic group: 34.9 months (8, 57) after treatment with the high dose (n = 10) of immunotherapy and 24.0 months (11, 35) with the low dose (n = 24). The median time to bone scan progression in the radiologic group was 5.0 months (2.6, 11.6) with the high dose and 2.8 months (2.8, 5.7) with the low dose. In the rising-PSA group (n = 21) receiving the low dose, the median time to bone scan progression was 5.9 months (5.6, not reached), and median survival was 37.5 months (29, 56). No dose-limiting or autoimmune toxicities were seen; the most common adverse events were injection site reaction and fatigue.

CONCLUSIONS

These results suggest that this GM-CSF-secreting, allogeneic cellular immunotherapy is well tolerated and may have clinical activity in patients with metastatic HRPC. Phase 3 trials to confirm these results are under way.

Renal cell carcinoma metastatic to the gallbladder or prostate: two case reports

Although metastatic renal cell carcinoma (RCC) is not uncommon, dissemination to the gallbladder or prostate is very rare. We present 1 case of RCC with synchronous metastasis to the gallbladder and 1 case of RCC with metachronous metastasis to the prostate. These cases illustrate the propensity of RCC for unpredictable presentation and unusual sites of metastases. The first case also illustrates the benefit of adjuvant nephrectomy with excision of a solitary metastasis. Patterns of RCC metastases and flow cytometric analysis of RCC are discussed.

Evaluation of pediatric cadaver kidneys transplanted into adult recipients receiving cyclosporine

The major problem in clinical transplantation is the imbalance between the need for cadaveric organs and the available numbers of donors. If pediatric kidneys were transplanted into adult recipients when no pediatric recipient was available, the potential number of renal donors would be increased by 15 to 20%. Some centers are reluctant to use pediatric kidneys for adult recipients because of recent reports indicating poorer patient and allograft survival, increased delayed graft function, increased post-transplant hypertension and increased technical complication. (There also has been concern that the nephrotoxic effect of cyclosporine A would retard the organ growth that is necessary to provide normal renal function in adults.) A retrospective analysis was performed on 18 adult recipients who received kidneys from cadaver donors 14 months to 12 years old (group 1). These patients were compared to 106 adult recipients who received kidneys from donors greater than 12 years old (group 2). Actuarial patient survival at 1 year was 85% for group 1 and 95.8% for group 2 (p equals 0.13), while 1-year actuarial allograft survival was 83.1% for group 1 and 81.1% for group 2 (p equals 0.87). There was no significant difference between groups 1 and 2 in the frequency of delayed graft function, serum creatinine at 1, 3 and 6 months after transplantation, incidence of post-transplant hypertension or frequency of surgical complications. It is of interest that the pediatric kidneys had significant growth during the initial post-transplant month. Sonographic examination at postoperative days 1 and 30 demonstrated a mean increase in size from 80.7 to 143.5 cm. (p less than 0.001). In this series pediatric kidneys were safe and effective donor organs in adult recipients, and increased the available number of organs by 15%.