Mistletoe Plant Extract in Patients with Nonmuscle Invasive Bladder Cancer: Results of a Phase Ib/IIa Single Group Dose Escalation Study.

PURPOSE: We determined the maximum tolerated dose, safety and effectiveness of intravesical instillation of mistletoe extract after transurethral resection of nonmuscle invasive bladder cancer. MATERIALS AND METHODS: In this single group dose escalation study patients with nonmuscle invasive bladder cancer were treated with weekly instillations of mistletoe extract for 6 weeks. Four weeks before instillation therapy all patients underwent transurethral resection of bladder tumors. During this procedure a marker tumor was left. At 12 weeks after the start of instillation therapy transurethral resection of the marker tumor or biopsy of the former marker tumor location was done so that patients were tumor free when entering followup until week 48. During the followup clinical assessment laboratory tests for safety and cystoscopy were done every 12 weeks. RESULTS: A total of 36 patients were treated with increasing doses of mistletoe extract. We found no dose limiting toxicity up to a dose of 675 mg of plant extract. Besides local reactions we saw hints that pyrexia may develop. All adverse events were well manageable. At 12 weeks a marker tumor remission rate of 55.6% (95% CI 38.1 to 72.1) was achieved. At 1 year a recurrence rate of 26.3% (95% CI 9.1 to 51.2) was observed. CONCLUSIONS: In this study intravesical instillation of mistletoe extract as treatment in patients with nonmuscle invasive bladder cancer was shown to be safe and well tolerated. Promising data on efficacy were observed and will be further investigated in a phase III study.

Prospective randomized double-blind multicentre phase II study comparing gemcitabine and cisplatin plus sorafenib chemotherapy with gemcitabine and cisplatin plus placebo in locally advanced and/or metastasized urothelial cancer: SUSE (AUO-AB 31/05).

OBJECTIVE: To evaluate the efficacy and safety of gemcitabine and cisplatin in combination with sorafenib, a tyrosine-kinase inhibitor, compared with chemotherapy alone as first-line treatment in advanced urothelial cancer. PATIENTS AND METHODS: The study was a randomized phase II trial. Its primary aim was to show an improvement in progression-free survival (PFS) of 4.5 months by adding sorafenib to conventional chemotherapy. Secondary objectives were objective response rate (ORR), overall survival (OS) and toxicity. The patients included in the trial had histologically confirmed locally advanced and/or metastatic urothelial cancer of the bladder or upper urinary tract. Chemotherapy with gemcitabine (1250 mg/qm on days 1 and 8) and cisplatin (70 mg/qm on day 1) repeated every 21 days, was administered to all patients in a double-blind randomization of additional sorafenib (400 mg twice daily) vs placebo (two tablets twice daily) on days 3-21. Treatment continued until progression or unacceptable toxicity, the maximum number of cycles was limited to eight. The response assessment was repeated after every two cycles. RESULTS: Between October 2006 and October 2010, 98 of 132 planned patients were recruited. Nine patients were ineligible. The final analysis included 40 patients in the sorafenib and 49 patients in the placebo arm. There were no significant differences between the two arms concerning ORR (sorafenib: complete response [CR] 12.5%, partial response [PR] 40%; placebo: CR 12%, PR 35%), median PFS (sorafenib: 6.3 months, placebo: 6.1 months) or OS (sorafenib: 11.3 months, placebo: 10.6 months). Toxicity was moderately higher in the sorafenib arm. Diarrrhoea occurred significantly more often in the sorafenib arm and hand-foot syndrome occurred only in the sorafenib arm. The study was closed prematurely because of slow recruitment. CONCLUSION: Although the addition of sorafenib to standard chemotherapy showed acceptable toxicity, the trial failed to show a 4.5 months improvement in PFS.

Stimulation of phospholipase C-epsilon by the M3 muscarinic acetylcholine receptor mediated by cyclic AMP and the GTPase Rap2B.

Stimulation of phospholipase C (PLC) by G(q)-coupled receptors such as the M(3) muscarinic acetylcholine receptor (mAChR) is caused by direct activation of PLC-beta enzymes by Galpha(q) proteins. We have recently shown that G(s)-coupled receptors can stimulate PLC-epsilon, apparently via formation of cyclic AMP and activation of the Ras-related GTPase Rap2B. Here we report that PLC stimulation by the M(3) mAChR expressed in HEK-293 cells also involves, in part, similar mechanisms. M(3) mAChR-mediated PLC stimulation and [Ca(2+)](i) increase were reduced by 2',5'-dideoxyadenosine (dd-Ado), a direct adenylyl cyclase inhibitor. On the other hand, overexpression of Galpha(s) or Epac1, a cyclic AMP-regulated guanine nucleotide exchange factor for Rap GTPases, enhanced M(3) mAChR-mediated PLC stimulation. Inactivation of Ras-related GTPases with clostridial toxins suppressed the M(3) mAChR responses. The inhibitory toxin effects were mimicked by expression of inactive Rap2B, but not of other inactive GTPases (Rac1, Ras, RalA, Rap1A, and Rap2A). Activation of the M(3) mAChR induced GTP loading of Rap2B, an effect strongly enhanced by overexpression of Galpha(s) and inhibited by dd-Ado. Overexpression of PLC-epsilon and PLC-beta1, but not PLC-gamma1 or PLC-delta1, enhanced M(3) mAChR-mediated PLC stimulation and [Ca(2+)](i) increase. In contrast, expression of a catalytically inactive PLC-epsilon mutant reduced PLC stimulation by the M(3) mAChR and abrogated the potentiating effect of Galpha(s). In conclusion, our findings suggest that PLC stimulation by the M(3) mAChR is a composite action of PLC-beta1 stimulation by Galpha(q) and stimulation of PLC-epsilon apparently mediated by G(s)-dependent cyclic AMP formation and subsequent activation of Rap2B.