Background: Neoadjuvant cisplatin-based combination chemotherapy improves survival in muscle invasive transitional cell carcinoma (MI-TCC). However response rates and survival remain suboptimal. We sought to evaluate the efficacy of cabazitaxel (CBZ) with cisplatin (CIS) in this setting. Methods: A single arm phase 2 study was designed with 80% power to detect an objective response rate (ORR) of >35%. Patients with MI-TCC were included if fit to receive neoadjuvant chemotherapy and to undergo radical cystectomy. Treatment was with CIS 70mg/m² and CBZ 15mg/m² on day 1 of a 21 day cycle, for 4 cycles prior to surgery. Primary prophylaxis was with pegylated GCSF. Toxicity was recorded using CTCAE v.4.03. Objective response was defined as a reduction in Tumour (T) stage from T2 or greater at diagnosis, to T1 or less at radical cystectomy. QoL data was assessed during and after chemotherapy using EQ-5D and EORTC-BLM30 questionnaires. Results: 28 patients were enrolled with median age 68.6 years (range 47-79). Response outcome (first 23 cases) and toxicity data (first 24 cases) are in this abstract; the remaining cases, currently scheduled for surgery, will be added to the final presentation. Pathological complete response (pCR) was observed in 7/23 patients (30.4%) and ORR was 56.5% (13/23). 18/24 (75%) completed 4 cycles; reasons for stopping were disease progression (2/24, 8.3%), adverse events (2/24, 8.3%) and patient choice (2/24, 8.3%). 7/24 patients (29%) experienced treatment related grade 3 and 4 adverse events. Conclusions: These results demonstrate that CIS and CBZ chemotherapy has an acceptable safety profile and is well tolerated in this setting. This combination shows promising efficacy (pCR 30.4%, ORR 56.5%) prior to definitive treatment for MI-TCC. Response outcomes for all patients and QoL data will be reported in the final presentation. Grade 3/4 adverse events. Clinical trial information: NCT01616875