Julie G. Beitz

Combined modality therapy for stage IIIA non-small cell carcinoma of the lung

53 patients with stage IIIA non-small cell carcinoma of the lung (NSCCL) were treated with multimodality therapy consisting of induction radiotherapy (55.8 Gy) and two cycles of concurrent chemotherapy with cisplatin, 25 mg/m2 for 4 days by continuous infusion and bolus etoposide, 100 mg/m2 on days 2 and 4 of each cycle followed by surgery and adjuvant chemotherapy. Of 53 evaluable patients, 47 achieved clinical responses (9 complete response, 38 partial response) after induction therapy for a response rate of 89%. 47 patients were resectable after induction therapy, but 8 patients refused surgery and 6 patients were not eligible for surgery based on poor pulmonary function (medical contraindications). 33 patients underwent thoracotomy and in 6 patients, resection was technically unfeasible. Thus complete surgical resection was accomplished in 27 patients. After all therapy, 28 patients achieved a complete response (53%) and 19 patients a partial response (36%). Toxicities were mild. At a maximum of 75 months (median, 28 months) of follow-up, the median survival of the entire group is 24 months. The median survival of resected patients has not been reached; their 6-year survival rate is 55%. Unresected patients survived for a median of 11 months. This multimodality regimen is well-tolerated, induces a high response and resectability rate and prolongs survival in resected patients.

Anti-B16-F10 melanoma activity of a basic fibroblast growth factor-saporin mitotoxin.

Background. The authors attached basic fibroblast growth factor (FGF‐2), a growth factor for numerous tumors and normal cell types, to saporin (SAP), a ribosomeinactivating protein isolated from the plant Saponaria officinalis. The conjugate (FGF‐SAP) then was tested for antitumor activity using B16‐F10 melanoma cells. This rapidly growing murine melanoma cell line has been used classically as a model to screen antitumor agents.

Saporin toxins directed to basic fibroblast growth factor receptors effectively target human ovarian teratocarcinoma in an animal model

Background. The antitumor activity of the chemical conjugate and recombinant forms of the mitotoxin basic fibroblast growth factor (bFGF) saporin (SAP) and the bFGF receptor‐directed immunotoxin 11A8‐SAP against human ovarian teratocarcinoma PA‐1 was examined in athymic nude mice. Alternative administration schedules to prolong therapeutic efficacy were explored.

Receptors for platelet-derived growth factor on microvascular endothelial cells

Endothelial cells are widely thought to be unresponsive to platelet-derived growth factor (PDGF) and devoid of PDGF receptors. However, in examining the growth factor responses of microvascular endothelial cells isolated from human omental adipose tissue, we detected PDGF-induced tyrosine phosphorylation of an 180-kD glycoprotein, subsequently identified as the cellular receptor for PDGF by specific immunoprecipitation. Scatchard analysis of 125I-PDGF binding to human microvascular endothelial cells revealed 30,000 PDGF receptors/cell with a kD of 0.14 nM. PDGF stimulated tyrosine phosphorylation of PDGF and other cellular proteins in a dose- and time-dependent manner, with half-maximal receptor phosphorylation occurring at 0.3 nM recombinant human PDGF-BB within 1 min of PDGF exposure. Normal cellular consequences of receptor activation were also observed, including tyrosine phosphorylation of a 42-kD protein and serine phosphorylation of ribosomal protein S6. Furthermore, PDGF was mitogenic for these cells. The finding of functional PDGF receptors on human microvascular endothelial cells suggests an important direct role for PDGF in neovascularization.

Phase I Trial of High-Dose Infused Zidovudine Combined with Leucovorin plus Fluorouracil

This phase I trial evaluated a high-dose, short-term infusion of zidovudine (AZT) following oral leucovorin (LV) and bolus 5-fluorouracil (FUra). Thirteen patients with metastatic cancer received 30 cycles of therapy. Plasma monitoring demonstrated a dose-dependent increase in peak plasma levels of AZT through the range of dose levels, from 104.3 +/- 8.7 microM at the 1.5 g/m2 dose of AZT to 1312.6 +/- 165.9 microM at the 11.0 g/m2 dose. While AZT did not potentiate the usual clinical toxicities of LV plus FUra, an unexpected finding of symptomatic hypotension during the AZT infusion was the dose-limiting toxicity in this trial. One partial response was observed in a previously untreated patient with metastatic colorectal cancer. The maximal tolerated dose of AZT, 7.0 g/m2 over 2 hr, is recommended for future phase II evaluation of this novel combination.

Phase II study of 5-fluoruracil leucovorin and azidothymidine in patients with metastatic colorectal cancer

The primary objective of this study was to determine the response rate of patients with metastatic colorectal cancer to combined therapy with 5-fluorouracil (5-FU), leucovorin, and intravenous azidothymidine (AZT), a thymidine nucleoside analog. By itself, AZT has limited antineoplastic efficacy. However, experimental studies indicate that 5-FU enhances the antitumor activity of AZT by inhibiting synthesis of normal thymidine nucleotides with which AZT competes for incorporation into nucleic acids. A phase I study defined the maximum tolerated dose of AZT as 7 g/m2 with hypotension during the infusion being the dose-limiting toxicity. A phase II study was performed with oral leucovorin (100 mg p.o. hourly for 4 h prior to 5-FU and 4 h and 8 h after 5-FU), bolus 5-FU (400 mg/m2) followed 1 h later by a 2-h infusion of AZT (7 g/m2). Treatment was given weekly for 4 weeks followed by a 1-week break, which constituted a cycle of therapy. Responses were evaluated after every two cycles. Patients continued on therapy as long as they tolerated treatment and did not have progressive disease. Of 15 evaluable patients who had received no chemotherapy there was 1 complete response and 4 partial responses (a 33% response rate), whereas only 1 of 6 patients who had received prior adjuvant chemotherapy had a partial response (17%). An additional 10 patients had stable disease lasting 2–14 months. Therapy was well tolerated with the only one instance each of grade 3 nausea and vomiting, diarrhea, anemia, and hypotension. Approximately 50% of treatments were accompanied by mild hypotension, which was easily corrected by increasing the rate of normal saline infusion. There was no difficulty administering this regimen in the outpatient setting. While the overall response rate (29%) is comparable to that seen with combinations of 5-FU and leucovorin alone, in most reported series a considerably higher dose of 5-FU was utilized than in this study. Since patients in the present study experienced relatively little 5-FU toxicity, increasing the dose of 5-FU in this regimen would appear to be feasible and might result in a higher response rate.

A phase I/II trial of 5-fluorouracil and etoposide in metastatic colorectal carcinoma.

Twenty-two patients with metastatic colorectal carcinoma were treated in a Phase I-II study of combination therapy with 5-fluorouracil (5-FU) and etoposide (VP-16). Treatment consisted of weekly intravenous VP-16, 100–120 mg/M2, followed by 5-FU, 400–480 mg/M2, in 28-day cycles. Myelosuppression was the dose-limiting toxicity with a mean nadir leukocyte count of 3,600/mm3 and a mean nadir thrombocyte count of 101,000/mm3. There were no episodes of sepsis or bleeding. The tolerable dose for this regimen is VP-16, 110 mg/M2, and 5-FU, 440 mg/M2, weekly. A total of 63 cycles of chemotherapy were given. Although 10 patients had stabilization of disease, no partial or complete responses were documented. We conclude that there is no clinical support for the in vitro synergy observed with this combination. Further trials of this combination using this schedule in colorectal carcinoma are not indicated.