Topotecan for the treatment of recurrent and stage IVB carcinoma of the cervix

In Vitro and In Silico Characterization of an Antimalarial Compound with Antitumor Activity Targeting Human DNA Topoisomerase IB

Human DNA topoisomerase IB controls the topological state of supercoiled DNA through a complex catalytic cycle that consists of cleavage and religation reactions, allowing the progression of fundamental DNA metabolism. The catalytic steps of human DNA topoisomerase IB were analyzed in the presence of a drug, obtained by the open-access drug bank Medicines for Malaria Venture. The experiments indicate that the compound strongly and irreversibly inhibits the cleavage step of the enzyme reaction and reduces the cell viability of three different cancer cell lines. Molecular docking and molecular dynamics simulations suggest that the drug binds to the human DNA topoisomerase IB-DNA complex sitting inside the catalytic site of the enzyme, providing a molecular explanation for the cleavage-inhibition effect. For all these reasons, the aforementioned drug could be a possible lead compound for the development of an efficient anti-tumor molecule targeting human DNA topoisomerase IB.

Natural Compounds as Therapeutic Agents: The Case of Human Topoisomerase IB

Natural products are widely used as source for drugs development. An interesting example is represented by natural drugs developed against human topoisomerase IB, a ubiquitous enzyme involved in many cellular processes where several topological problems occur due the formation of supercoiled DNA. Human topoisomerase IB, involved in the solution of such problems relaxing the DNA cleaving and religating a single DNA strand, represents an important target in anticancer therapy. Several natural compounds inhibiting or poisoning this enzyme are under investigation as possible new drugs. This review summarizes the natural products that target human topoisomerase IB that may be used as the lead compounds to develop new anticancer drugs. Moreover, the natural compounds and their derivatives that are in clinical trial are also commented on.

Drug Repositioning Screen on a New Primary Cell Line Identifies Potent Therapeutics for Glioblastoma

Glioblastoma is a malignant brain cancer with limited treatment options and high mortality rate. While established glioblastoma cell line models provide valuable information, they ultimately lose most primary characteristics of tumors under long-term serum culture conditions. Therefore, established cell lines do not necessarily recapitulate genetic and morphological characteristics of real tumors. In this study, in line with the growing interest in using primary cell line models derived from patient tissue, we generated a primary glioblastoma cell line, KUGBM8 and characterized its genetic alterations, long term growth ability, tumor formation capacity and its response to Temozolomide, the front-line chemotherapy utilized clinically. In addition, we performed a drug repurposing screen on the KUGBM8 cell line to identify FDA-approved agents that can be incorporated into glioblastoma treatment regimen and identified Topotecan as a lead drug among 1,200 drugs. We showed Topotecan can induce cell death in KUGBM8 and other primary cell lines and cooperate with Temozolomide in low dosage combinations. Together, our study provides a new primary cell line model that can be suitable for both in vitro and in vivo studies and suggests that Topotecan can offer promise as a therapeutic approach for glioblastoma.

Is the routine use of bevacizumab in the treatment of women with advanced or recurrent cancer of the cervix sustainable?

BACKGROUND

New chemotherapy combinations are being tested for the treatment of women with advanced, persistent or recurrent cervical cancer. We sought to evaluate the cost effectiveness of some newer combination therapies in cervical cancer.

PATIENTS AND METHODS

A cost effectiveness decision model was used to analyze Gynecologic Oncology Group 240. All regimens were modeled for seven cycles. The regimens studied are as follows: regimen 1, cisplatin/paclitaxel (CP); regimen 2, CP with bevacizumab (CP+B); regimen 3, paclitaxel/topotecan (PT); and regimen 4, PT with bevacizumab (PT+B). Overall survival, cost, and complications were studied. Sensitivity analyses were performed.

RESULTS

Mean chemotherapy costs over mean total costs for seven cycles of each follows: CP $571/$32,966; CP+B $61,671/$96,842; PT $9,211/$71,620; and PT+B $70,312/$109,211. Incremental cost-effectiveness ratio (ICER) for CP+B was $133,559/quality adjusted life year (QALY). ICER for PT+B was $124,576/QALY. To achieve an incremental ICER for CP+B:CP of <$50,000/QALY gained, the mean overall survival has to increase from 1.1 years with CP to 3.5 years with CP+B. An ICER <$50,000/QALY for the other regimens would take a survival of >10 years for PT and 4.1 years for PT+B. Treating 1,000 women with cervical cancer with CP+B would cost almost double the cost of treating >18,000 women with ovarian cancer annually (carboplatin/paclitaxel).

CONCLUSION

CP is the most cost effective regimen. A 12-month increase in overall survival will not even make the newer combinations cost effective. Currently, the use of bevacizumab is not sustainable at today's costs.

Correlations Between Radiation Dose in Bone Marrow and Hematological Toxicity in Patients With Cervical Cancer: A Comparison of 3DCRT, IMRT, and RapidARC

Objective

To comparatively evaluate the hematological toxicity (HT) associated with 3 concurrent chemoradiotherapies that are routinely used to treat cervical cancer, including 3-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT), and RapidARC and to establish a new normal tissue complication probability model of bone marrow (BM) to predict HT in cervical cancer patients undergoing concurrent chemoradiotherapy.

Methods

Patients with cervical cancer (N = 100) who received concurrent cisplatin and whole-pelvic radiotherapy were enrolled in this study. Dosimetric parameters (including V10, V20, V30, and V40 and mean doses to the pelvic bone) and HT were analyzed.

Results

The V20, V30, and V40 and mean doses to the BM were lower in the IMRT and RapidARC groups than in the 3DCRT group, and the RapidARC group had higher V10 and V40 and mean values than the IMRT group. The V20, V30, and V40 and the mean dose to the pelvic bone were positively correlated with HT. Generalized linear normal tissue complication probability models of white blood cell (WBC) and absolute neutrophil cell (ANC) nadirs and BM V20 were established as follows: WBC nadir = 3.382 – 4.056 • V20 + 0.295 • baseline of WBC (adjusted R2 = 0.246, F = 15.847) and ANC nadir = 2.438 – 2.780 • V20 + 0.233 • baseline of ANC (adjusted R2 = 0.236, F = 16.282).

Conclusions

This study suggests that IMRT results in milder hematological toxicity than either 3DCRT or RapidARC. Dosimetric parameters were associated with the incidence of HT in cervical cancer patients who received concurrent chemoradiotherapies.

Treatment of advanced or recurrent cervical cancer with Cisplatin or Cisplatin containing regimens: a cost effective analysis

Background: Trials have demonstrated improvements in survival with adding paclitaxel (P) or topotecan (T) to cisplatin (C) for the treatment of advanced cervical cancer. We sought to evaluate the cost effectiveness of these regimens.

Methods: A decision model was developed based on Gynecologic Oncology Group (GOG) protocols 169 and 179. Arm 1 is 6 cycles of cisplatin. Arm 2 is 6 cycles of CP while arm 3 is 6 cycles of CT. Parameters include overall survival (OS), cost and complications. Sensitivity analyses were performed.

Results: The incremental cost-effectiveness ratio (ICER) for C versus CP is $13,654/quality-adjusted life-year (QALY) gained. For CT compared to C, the ICER is $152,327/QALY. When compared simultaneously, CT is dominated. At a willingness to pay (WTP) threshold of $50,000/QALY, C is the preferred option but CP is acceptable. Sensitivity analyses suggest that CT would become the preferred option if it was to improve OS to 24 months (compared to 9.4 months).

Conclusions: In this model, CP is an acceptable alternative to cisplatin for the treatment of these patients with an increase in cost of only $13,654/QALY. The addition of topotecan did not increase survival enough to justify the increased cost.