CCTG PR21: A randomized phase II study of [177lu]lu-PSMA-617 verus docetaxel in patients with metastatic castration-resistant prostate cancer and PSMA-positive disease (NCT04663997). Conferences uri icon

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  • TPS5110 Background: [177Lu]Lu-PSMA-617 improves outcome in men with metastatic, PSMA positive CRPC post androgen pathway inhibitor therapy and taxane chemotherapy compared to standard care (excluding chemotherapy, immunotherapy, radium-223 and investigational drugs; Sartor et al, NEJM 2021). The relative efficacy, adverse event experience and impact on QOL of [177Lu]Lu-PSMA-617 compared to docetaxel chemotherapy in this patient population is unknown. We hypothesize that [177Lu]Lu-PSMA-617 will improve radiographic PFS (rPFS) compared to docetaxel chemotherapy with a favourable safety and tolerability profile. Methods: CCTG PR21 is a Canadian Cancer Trials Group randomized phase II trial with a primary objective to compare rPFS between [177Lu]Lu-PSMA-617 7.4 GBq (+/- 10%) IV q 6 weekly (maximum 6 cycles) versus docetaxel 75 mg/m2 q 3 weekly (maximum 12 cycles). Secondary objectives are to compare the two arms with respect to: 6-month PFS rate (PCWG3 and RECIST 1.1), second rPFS after crossover to the alternate therapy, time to commencement of 3rd line systemic therapy, OS, PSA decline from baseline, clinical benefit rate and adverse events. Tertiary objectives include evaluation of QOL (FACT-P and EQ5D-5L), cost effectiveness, ctDNA and radiographic based prognostic and predictive biomarkers, dosimetry based approach to measurement of [177Lu]Lu-PSMA-617 activity and creation of tissue and image biobanks. Key eligibility criteria include: mCRPC with PSMA positive disease using 18F or 68Ga radionuclide label, progression on ADT + ARPI therapy (using PSA, RECIST 1.1 or PCWG3 criteria) and adequate organ function. Statistical Design: Patients are allocated in 1:1 ratio to [177Lu]Lu-PSMA-617 or docetaxel balanced for stratification factors of ECOG PS, LDH, visceral metastases, previous docetaxel in the castration sensitive setting > 1 year prior to enrollment as well as centre. Assuming a 6-month median rPFS for the control group, the detection of a hazard ratio (HR) of 0.67 with 80% power using a 1-sided 5% level test will require accrual of 200 participants in 24 months with 12-month follow-up to trigger the primary analysis. Conduct to Date: Study activation Dec 17 2020. Enrollment as of January 31 2022: 25. The DSMC last reviewed and recommended continuation of the trial in December 2021. Clinical trial information: NCT04663997.


  • Chi, Kim N
  • Saad, Fred
  • Parulekar, Wendy R
  • Emmenegger, Urban
  • Hotte, Sebastien
  • Pouliot, Frederic
  • Bauman, Glenn
  • Zukotynski, Katherine
  • Peacock, Stuart
  • Wyatt, Alexander William
  • Beauregard, Jean-Mathieu
  • Lee, Justin
  • Uribe, Carlos
  • Dellar, Conor
  • Ding, Keyue
  • Benard, Francois

publication date

  • June 1, 2022