Phase II study of loading-dose ibandronate treatment in patients with breast cancer and bone metastases suffering from moderate to severe pain.

BACKGROUND: The aim of this study was to determine the efficacy and safety of loading-dose intravenous (i.v.) ibandronate in women with breast cancer and bone metastases. PATIENTS AND METHODS: In this prospective, phase II, open-label study, 13 women with breast cancer, bone metastases, and moderate/severe bone pain received ibandronate 6 mg/day (i.v. loading-dose 15 min infusion over 3 consecutive days) with follow-up until day 14. Endpoints included pain response (primary), duration until pain response, analgesic use, Karnofsky index, safety (including hematologic, biochemical, and urine examinations), and adverse events. RESULTS: Pain intensity decreased on days 7 and 14 versus day 1 (mean visual analogue scale score: 3.2 ± 2.2 and 3.0 ± 2.1 versus 6.1 ± 0.9, respectively; p < 0.01 for both). Mean time to pain response was 8.2 ± 3.3 days. Mean rate of analgesic use decreased (69.2%, 16.7% and 15.4% on days 1, 7 and 14, respectively). Mean Karnofsky index score increased (80.8 ± 13.1 and 80.8 ± 13.2, on days 7 and 14 versus 77.7 ± 11.7 on day 1; p < 0.05 on both days). CONCLUSION: Bone pain and analgesic use decreased in women with breast cancer and bone metastases following loading dose i.v. ibandronate which was well-tolerated with no renal safety concerns.

Pharmacokinetic and pharmacodynamic analysis of 5-aza-2'-deoxycytidine (decitabine) in the design of its dose-schedule for cancer therapy.

5-Aza-2'-deoxycytidine (5-AZA-CdR, decitabine), an epigenetic drug that inhibits DNA methylation, is currently used to treat myelodysplastic syndrome (MDS), and is under investigation for treating acute myeloid leukemia (AML) and other malignancies. 5-AZA-CdR can reactivate tumor suppressor genes silenced by aberrant DNA methylation, a frequent event in all types of cancer. Because this epigenetic change is reversible, it is a good target for 5-AZA-CdR therapy. We have reviewed the preclinical data of 5-AZA-CdR to analyze the concentrations and exposure times required to eradicate cancer stem cells. We analyzed the dose-schedules used in animal models that show potent antineoplastic activity of 5-AZA-CdR. We attempted to correlate the preclinical data with the responses obtained in clinical trials of 5-AZA-CdR in patients with cancer. The pharmacokinetics and drug distribution of 5-AZA-CdR are key parameters because adequate therapeutic drug levels are required to eliminate cancer stem cells in all anatomic compartments. The plasma half-life of 5-AZA-CdR in humans is approximately 20 minutes due to the high levels in the liver of cytidine deaminase, the enzyme that inactivates this analogue. This provides a rationale to use an inhibitor of cytidine deaminase in combination with 5-AZA-CdR. Low-dose 5-AZA-CdR is effective for MDS and AML and can induce complete remissions (CR). However, maintenance of CR with low-dose 5-AZA-CdR is difficult. Based on analyses of preclinical and clinical data, low dose 5-AZA-CdR has the potential to be an effective form of therapy in some patients with cancer. For patients who do not respond to low dose therapy we recommend dose-intensive treatment with 5-AZA-CdR. Patients who are candidates for intensive dose 5-AZA-CdR should have a good bone marrow status so as to permit adequate recovery from myelosuppression, the major toxicity of 5-AZA-CdR. Solid tumors are also interesting targets for therapy with 5-AZA-CdR. Both low dose and intensive therapy with 5-AZA-CdR can reduce the proliferative potential of tumor stem cells in animal models. We propose novel dose schedules of 5-AZA-CdR for investigation in patients with cancer. The full chemotherapeutic potential of 5-AZA-CdR to treat cancer merits further clinical investigation and can only be realized when its optimal dose-schedule is determined.