CTC-STOP Trial 

Utilising Circulating Tumour Cell (CTC) counts to optimize systemic therapy of metastatic prostate cancer 

Disease site: Prostate cancer, Urological cancer   

Treatment modality: Systemic therapy, chemotherapy

Status: In follow-up

Trial details

CTC-STOP is an international non-inferiority phase III trial for patients with metastatic castration resistant prostate cancer (mCRPC) who have bone metastases but no measurable disease and who have previously received treatment with abiraterone/ enzalutamide and who are recommended for treatment with docetaxel. 

The primary objective is to determine if the use of serial CTC counts can direct early discontinuation of docetaxel chemotherapy in patients with mCRPC without adversely impacting overall survival (OS), when compared with standard approaches to guide treatment switch decisions.

A total of 1,178 participants with a CTC count ≥5 cells per 7.5 mL blood will be randomised 1:1 to either the:

• Control group (standard of care): Standard first line docetaxel treatment for 10 cycles, or until disease progression as determined by the treating clinician. CTC testing results will not be disclosed to patients and treating clinicians.
• Intervention group (CTC guided treatment): Standard first line docetaxel treatment for 10 cycles, or until disease progression as defined by CTC criteria and/or disease progression as determined by the treating clinician. CTC results will be available to the treating clinician to guide decision-making.

All patients will commence first line chemotherapy with docetaxel 75mg/m² three-weekly and will receive a minimum of 3 cycles of treatment before any recommendation to discontinue first-line docetaxel.  Patients who discontinue first line docetaxel according to the criteria for each group will be switched to second line chemotherapy with cabazitaxel.  After progression on cabazitaxel or completion of 10 cycles, patients will be followed up for survival every three months until end of study.

A feasibility analysis will be performed after the first 200 patients have been randomised and followed for at least 24 weeks or until docetaxel discontinuation (whatever occurs first). If 75% or more of the patients in the intervention group in whom CTC progression criteria are met perform a chemotherapy switch as recommended, the trial will continue to reach its target accrual.

Further information

Chief Investigator: Professor Johann de Bono, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust

ICR-CTSU Scientific Lead: Professor Emma Hall

Trial management contact: [email protected]

ISRCTN: ISRCTN82499869

Sponsor: The Institute of Cancer Research

Funding: Prostate Cancer UK (The Movember Centre of Excellence for Prostate Cancer; PCUK - CEO13-2-002); Sanofi; Janssen Diagnostics

View CTC-STOP on the National Institute for Health Research website: NIHR - Be Part Of Research

A plain English summary will be added once available.

Publications and presentations

Hill E, Porta N, Miranda Ml, Hyslop M, Flohr P, Lewis R, Heath E, Snowdon C, De Bono J, Hall E. Automated solution for importing lab test results from a laboratory information management system into an electronic data capture system. Accepted for poster presentation at: 38^th Annual Meeting of the Society for Clinical Trials/4th International Clinical Trials Methodology Conference; 2017 May 7–10; Liverpool, UK.

Hall E, Porta N, Lorente D, De Bono J; on behalf of the CTC-STOP Protocol Development Group. Utilizing circulating tumour cell (CTC) counts to optimize systemic therapy of metastatic prostate cancer: a phase III randomised trial. Poster presentation at: Methods for Evaluating Medical Tests and Biomarkers Symposium; 2016 July 19–20; Birmingham, UK.

Lorente D, Olmos D, Mateo J, Bianchini D, Seed G, Fleischer M, Danila D, Flohr P, Crespo M, Figueiredo I, Miranda S, Baeten K, Molina A, Kheoh T, McCormack R, Terstappen LWMM, Scher HI, De Bono J. Decline in circulating tumor cell count and treatment outcome in advanced prostate cancer. Eur Urol 2016;70(6):985–992.

Lorente D, Ravi P, Mehra N, Pezaro C, Omlin A, Gilman A, Miranda M, Rescigno P, Kolinsky M, Porta N, Bianchini D, Tunariu N, Perez Lopez R, Mateo J, Payne H, Terstappen LW, Ijzerman M, Hall E, De Bono J. Interrogating metastatic prostate cancer treatment switch decisions. Eur Urol Focus 2016; In Press, Corrected Proof.

Lorente D, Ravi P, Mehra N, Pezaro C, Omlin A, Miranda M, Payne H, Hall E, Terstappen LW, Ijzerman M, De Bono J. Interrogating metastatic prostate cancer treatment switch decisions. J Clin Oncol 2016;34(Suppl 2S):296.