Phase I trial of interferon-gamma (IFN-gamma) retroviral vector administered intratumorally to patients with metastatic melanoma

BACKGROUND

Interferon-gamma (IFN-gamma) gene/retroviral vector cell vaccinations have generated protective responses from unmodified tumor cell challenges as well as a regression of established tumors in animal models. The purpose of this trial was to determine the feasibility and safety of a direct intratumoral injection of IFN-gamma retroviral vector in advanced melanoma patients.

METHODS

This was a phase I study, in which 13 patients received a single daily injection of a retroviral vector with the IFN-gamma gene for 5 consecutive days (1.5 x 10(8) colony-forming units total dose); patients subsequently underwent resection of the injected lesion to confirm DNA transduction in situ.

RESULTS

No toxicity related to the injected vector was observed. Replication competent retrovirus was not observed in any prepared samples (n = 65). IFN-gamma expression was confirmed in 3 of 10 harvested tumor samples; one was equivocal, and DNA transduction was unable to be confirmed by enzyme-linked immunospot assay in six samples.

CONCLUSIONS

An injection of IFN-gamma gene/retroviral vector is well tolerated. DNA transduction was demonstrated in human subjects, confirming the feasibility of the direct injection approach for the gene therapy of solid tumors. Further trials to determine optimal schedule and potential efficacy are indicated.

Phase I trial of retroviral vector-mediated interferon (IFN)-gamma gene transfer into autologous tumor cells in patients with metastatic melanoma

The purpose of this study was to determine the safety of treating melanoma patients with retroviral vector-mediated interferon (IFN)-gamma gene-transduced autologous tumor cells. We designed a phase I study, in which irradiated, autologous, transduced melanoma cells expressing the IFN-gamma gene were injected subcutaneously every 2 weeks with escalating cell doses for six injections. Tumor tissue was harvested from 58 patients with metastatic melanoma. Twelve patients had sufficient expansion of autologous tumor (0.56-160 x 10(7) cells) and adequate IFN-gamma expression after gene transduction (2-79,000 U/10(6) cells/24 hours) for injections. Five patients received injections. No toxicity was attributed to the IFN-gamma retroviral vector in the patients injected. One of the injected patients remains disease-free after 13 injections, following the surgical removal of brain, adrenal, and lung metastases. We found that injections of autologous tumor cells transduced by IFN-gamma gene were well tolerated. However, the ability to develop primary autologous melanoma cell lines was limited, and only a minority of patients were injected.

Phase II study of mitoxantrone, leucovorin, and infusional fluorouracil for treatment of metastatic breast cancer

A new combination of mitoxantrone, folinic acid (leucovorin), and infusional fluorouracil (5-FU) was administered to 57 previously treated patients with metastatic breast cancer to evaluate the response rate, response duration, and toxicity of this regimen. Fifty-three patients who received 313 courses of therapy were assessable for response and toxicity. Median age was 48 years (range, 33 to 80 years), and the patients had received an average of 1.5 chemotherapy regimens before this study. Of 53 assessable patients, 24 (45%, or 42% of all entered patients) experienced partial responses (PRs) with a median duration of 6 months (range, 2 to 13 months). Nine (69%) of 13 assessable patients without prior doxorubicin treatment responded, compared with 15 (38%) of 40 with prior doxorubicin (P less than .05). Toxicity was generally mild with dose reductions necessitated more often by mucositis and/or diarrhea than by myelosuppression. One patient with prior high-dose doxorubicin treatment developed congestive heart failure. The combination of mitoxantrone, leucovorin, and infusional 5-FU is an active and well-tolerated regimen for metastatic breast cancer and deserves further evaluation in patients without prior doxorubicin therapy.