Phase II trial of gallium nitrate, amonafide and teniposide in metastatic non-small cell lung cancer. An Eastern Cooperative Oncology Group study (E2588)

Clinical pharmacology and clinical trials of ribonucleotide reductase inhibitors: is it a viable cancer therapy?

PURPOSE

Ribonucleotide reductase (RR) enzymes (RR1 and RR2) play an important role in the reduction of ribonucleotides to deoxyribonucleotides which is involved in DNA replication and repair. Augmented RR activity has been ascribed to uncontrolled cell growth and tumorigenic transformation.

METHODS

This review mainly focuses on several biological and chemical RR inhibitors (e.g., siRNA, GTI-2040, GTI-2501, triapine, gemcitabine, and clofarabine) that have been evaluated in clinical trials with promising anticancer activity from 1960's till 2016. A summary on whether their monotherapy or combination is still effective for further use is discussed.

RESULTS

Among the RR2 inhibitors evaluated, GTI-2040, siRNA, gallium nitrate and didox were more efficacious as a monotherapy, whereas triapine was found to be more efficacious as combination agent. Hydroxyurea is currently used more in combination therapy, even though it is efficacious as a monotherapy. Gallium nitrate showed mixed results in combination therapy, while the combination activity of didox is yet to be evaluated. RR1 inhibitors that have long been used in chemotherapy such as gemcitabine, cladribine, fludarabine and clofarabine are currently used mostly as a combination therapy, but are equally efficacious as a monotherapy, except tezacitabine which did not progress beyond phase I trials.

CONCLUSIONS

Based on the results of clinical trials, we conclude that RR inhibitors are viable treatment options, either as a monotherapy or as a combination in cancer chemotherapy. With the recent advances made in cancer biology, further development of RR inhibitors with improved efficacy and reduced toxicity is possible for treatment of variety of cancers.

Biological study of the effect of water soluble [N-(2-hydroxybenzyl)-L-aspartato] gallium complexes on breast carcinoma and fibrosarcoma cells

Two water soluble gallium complexes described as [Ga(III)LCl], where L is the deprotonated form of N-2-hydroxybenzyl aspartic acid derivatives, were synthesized and characterized by (1)H NMR, (13)C NMR, FT-IR, mass spectrometry, and elemental analysis. The 2-(5-chloro-2-hydroxybenzylamino)succinic acid derivative (GS2) has been found to be a promising anticancer drug candidate. This compound was found to be more cytotoxic against human breast carcinoma MDA-MB231 and fibrosarcoma HT-1080 cell lines than the unsubstituted derivative and GaCl3. GS2 was able to induce apoptosis through downregulation of AKT phosphorylation, G2M arrest in cell cycle, and caspase 3/7 pathway. This gallium complex was found to induce an increase in mitochondrial ROS level in HT-1080 cells but not in MDA-MB231 cells. This suggests that the mechanism of action of GS2 would not be mediated by the drug-induced oxidative stress but probably by directly and indirectly inhibiting the AKT cell-signaling pathway.

Changes in the natural history of nonsmall cell lung cancer (NSCLC)--comparison of outcomes and characteristics in patients with advanced NSCLC entered in Eastern Cooperative Oncology Group trials before and after 1990

BACKGROUND

Demographic factors and treatment regimens were evaluated in relation to differences in outcome between patients with advanced nonsmall cell lung cancer (NSCLC) who were diagnosed and treated on Eastern Cooperative Oncology Group Phase II and III trials from 1981 to 1990 and from 1991 to 2000.

METHODS

In this retrospective analysis, 6 advanced NSCLC trials were identified between 1981 and 1990, and 3 trials were identified after 1990. Patient characteristics (n = 3398 patients) and other clinical outcomes were analyzed, including progression-free survival (PFS) and overall survival (OS).

RESULTS

Patients who entered on trials after 1990 more likely were women, received a cisplatin-containing regimen, had a performance status of 0 or 1, had Stage IIIB (vs. Stage IV) disease, had tumors with adenocarcinoma histology, had weight loss < or = 10%, and had pulmonary-only metastases (although more total metastases and brain metastases) compared with patients who were diagnosed before 1990. OS was longer post-1990 than pre-1990 (8.2 months vs. 5.8 months pre-1990), and PFS was longer post-1990 (3.5 months vs. 2.6 months pre-1990; P<.001 for both). In addition, the median interval from the date of disease progression to death increased by nearly 62% in the later decade.

CONCLUSIONS

Improved survival in more recent NSCLC trials was explained in part by the enrollment of patients with more favorable prognostic factors. A change in the natural history of the disease was reflected by some of these changes, including increased numbers of women with the disease and changes in the patterns of metastases. Changes in eligibility criteria also accounted for some improvements in prognostic factors and improved second line therapies in the later decade. Thus, the survival improvements are likely to be multifactorial, with improved therapies also playing a major role.

Antineoplastic drugs that interfere with iron metabolism in cancer cells

Normal iron metabolism can be perturbed with iron chelators, toxic metals that bind to transferrin, toxic metals bound to transferrin or antineoplastic agents covalently linked to transferrin. These agents cause significant inhibition of tumor cell growth in cell culture and have been shown to have significant in vivo antineoplastic activity. Cell culture studies showed that deferoxamine mesylate inhibits cell growth and division in both the MCF-7 human breast and HeLa human cervical carcinoma cell lines. Animal studies demonstrated that when deferoxamine mesylate is injected intravenously into rats that are on a low iron diet, there is a significant reduction in the growth of 13762NF mammary adenocarcinomas. Gallium, indium and the antineoplastic agent cisplatin were bound to the iron binding site of transferrin and inhibit the growth of malignant carcinoma cell lines. Gallium-transferrin and indium-transferrin were at least 10 times more inhibitory to both MCF-7 and HeLa cell lines than their free salts. Further cell culture studies demonstrated that cisplatin-transferrin complexes act synergistically with doxorubicin to inhibit the growth of cultured MCF-7 cells. In a Phase I clinical trial of cisplatin-transferrin complex there was a 36% (four of 11 patients) response rate in breast cancer patients with advanced disease. In a second clinical study the sequential administration of deferoxamine mesylate (2 days at 6 g/day in 8 hrs), cisplatin-transferrin complex (7 days at 500 mg/day) and FAC (5-fluorouracil, doxorubicin and cyclophosphamide at 450, 45 and 450 mg/m2, respectively) to advanced breast cancer patients resulted in partial responses in seven of eight patients treated. Future work will concentrate on substituting transferrin based agents with daunorubicin or doxorubicin attached to the surface of the transferrin, and gallium or indium bound to the iron binding site, to increase efficacy of the second component of the sequential combination chemotherapy.