Efficacy and safety of nab-paclitaxel in patients with previously treated metastatic colorectal cancer: a phase II COLO-001 trial

Purpose: This single-arm, phase II trial evaluated nab-paclitaxel monotherapy in pretreated patients with metastatic colorectal cancer (mCRC). Methods: Patients with mCRC (RAS wild-type and RAS mutant cohorts) received nab-paclitaxel 125 mg/m² days 1, 8, and 15 (28-day cycle). The primary endpoint was investigator-assessed progression-free survival (PFS) rate at week 8; secondary endpoints included overall survival, overall response rate, and safety. Stage 1 planned enrollment was 15 patients per cohort per Simon 2-stage design. Stage 2 enrollment was to continue unless ≤8 of the first 15 patients per cohort achieved PFS at 8 weeks. Results: Stage 1 enrolled 41 patients (RAS wild type: n = 18; RAS mutant: n = 23). In both RAS cohorts, 3 of 15 patients initially enrolled were progression-free at week 8 (20%; 95% CI 4.0–48.0). Median PFS was 8.1 weeks (95% CI 7.7–8.6) and 7.9 weeks (95% CI 7.6–8.0) for RAS wild-type and RAS mutant cohorts, respectively. There were no complete or partial responses. The overall disease control rate was 16% (95% CI 6.0–32.0), and rates were similar in the RAS wild-type and RAS mutant cohorts (18 and 15%, respectively). No new safety signals were reported; the most common grade ≥3 adverse events included neutropenia, asthenia, and peripheral neuropathy. This study did not progress to stage 2 per the preplanned statistical stopping rule. Conclusions: In patients with heavily pretreated mCRC, nab-paclitaxel did not demonstrate promising antitumor activity; further assessment of nab-paclitaxel monotherapy in this population of patients is not supported. Trial registration: NCT02103062.