How does gemcitabine work

Cochrane

Six relevant randomized studies were identified, which differed in the number of patients per study (30 to 341 patients per study, a total of 704). All studies compared gemcitabine with an active control intervention and varied in the reporting of the endpoints. One study compared a single postoperative instillation of intravesical gemcitabine with an instillation of saline solution in 341 patients and found no significant difference in tumor recurrence rate (28% gemcitabine versus 39% Nacl) or recurrence-free survival (HR (hazard ratio) 0.95; 95% Confidence interval 0.64 to 1.39; p = 0.77). The rate of progression to advanced disease was greater with gemcitabine (2.4% versus 0.8%). Another study compared gemcitabine with intravesical mitomycin C and showed that the recurrence rate (28% versus 39%) and the progression rate (11% versus 18%) were lower with gemcitabine, but no statistical significance was achieved in either endpoint. The overall incidence of adverse events was significantly lower with gemcitabine (38.8% versus 72.2%, p = 0.02).

Three studies compared gemcitabine with intravesical Bacillus Calmette-Guérin (BCG), but a meta-analysis was not possible due to clinical heterogeneity. In untreated patients with moderate risk of tumor recurrence (mainly Ta-T1, without CIS), a study showed that gemcitabine and BCG had the same effect, with recurrence rates of 25% and 30% respectively (p = 0.92) and an equal overall rate of progression (p = 1.0). Dysuria (12.5% ​​versus 45%, p <0.05) and pollakiuria (10% versus 45%, p <0.001) occurred significantly less frequently with gemcitabine. In a second study in high-risk patients, the recurrence rate was significantly higher with gemcitabine compared to BCG (53.1% and 28.1%, p = 0.04) and the time to relapse was significantly shorter (25.5 compared to BCG) 39.4 months, p = 0.042). In a third study with high-risk patients who had become refractory to previous intravesical BCG therapy, gemcitabine had significantly fewer relapses (52.5% versus 87.5%, p = 0.002) and a longer time to recurrence ( 3.9 versus 3.1 months, p = 0.9) compared to BCG. Progression rates were similar in both groups (33% versus 37.5%, p = 0.12) with no significant differences in grade 2 or 3 toxicities.

A marker lesion study reported higher response rates when intravesical gemcitabine (2 g) was administered as three bi-weekly instillations (36%) or six weekly instillations (40%) compared to a single dose (9%).