Dalbavancin treats gram-positive bacteremia

New data, which were published in the Feb. 1, 2005, issue of Clinical Infectious Diseases, demonstrated that Vicuron Pharmaceuticals' investigational antibiotic, dalbavancin, administered once per week, is more effective in treating catheter-related bloodstream infections than is twice-daily treatment with vancomycin.

Dalbavancin is a novel second-generation lipoglycopeptide. It belongs to the same class as vancomycin, and it has been specifically designed as an improved alternative to vancomycin.

Patients in this open-label phase II trial were randomly assigned to receive either two doses of intravenous dalbavancin (1000 mg on day 1 and 500 mg on day 8) or intravenous vancomycin hydrochloride (1000 mg twice daily for 14 days).

The authors of the study noted that the organisms involved in the infections were Staphylococcus aureus, including methicillin-resistant S. aureus, coagulase-negative staphylococci, and Enterococcus faecalis. They added that these findings suggest cost advantages for dalbavancin and may offer flexibility for implementing new approaches to antibiotic treatment of adults with bacteremia. Furthermore, weekly dosing with dalbavancin may reduce the need for indwelling catheters.

In December, Vicuron submitted an NDA for dalbavancin for the treatment of complicated skin and soft tissue infections.

Prostate cancer vaccine improves survival Dendreon's investigational immunotherapy for the treatment of advanced prostate cancer, Provenge, significantly improved survival in men with asymptomatic, metastatic androgen-independent (hormone-refractory) prostate cancer. In the double-blind, placebo-controlled phase III trial, patients randomized to Provenge had a 4.5-month improvement in their median survival and a greater than threefold increase in survival at 36 months when compared with patients randomized to placebo. Provenge was also well tolerated.

Provenge is designed to stimulate the immune system to attack cells that express prostatic acid phosphatase (PAP), a protein that is expressed on approximately 95% of prostate cancer cells. The vaccine is created by mixing a synthetic version of PAP with dendritic cells harvested from the study patients. Dendreon's proprietary Antigen Delivery Cassette technology delivers small pieces of the PAP protein to a patient's antigen-presenting cells (APCs). These APCs activate other cells of the immune system to seek out and destroy PAP-containing prostate cancer cells.

Provenge is on FDA fast-track approval and is also being tested in combination with bevacizumab in a phase II trial of patients with hormone-sensitive prostate cancer.

Positive results halt trial for gastric cancer drug An independent panel of experts recommended stopping a phase III study of Pfizer's experimental drug for gastrointestinal stromal tumors (GIST), SU11248, after the study demonstrated efficacy and safety seven months ahead of schedule.

The trial included patients who have stopped responding to imatinib mesylate (Gleevec, Novartis), the current standard of care for GIST. Patients who had been receiving placebo now have the option of switching to SU11248.

In an earlier trial, researchers said that the tumors of patients with imatinib-resistant GIST either shrank or did not progress for six months or longer after treatment with SU11248.

SU11248 is a novel, oral multi-targeted cancer therapy that combines anti-angiogenic and antitumor activity to simultaneously stop the blood supply to, and directly attack, the tumor cells. It is believed to inhibit specific tyrosine kinases, including vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), KIT, and FLT3 receptor tyrosine kinases.

Pfizer is also studying SU11248 in phase III trials as a treatment for renal cell carcinoma. In an earlier small trial, one that involved patients with kidney cancer who failed to benefit from other treatments, tumors shrank in 33% of the patients. According to the researchers, that was a sixfold improvement compared with typical results from the best standard treatments.