Regorafenib or Tamoxifen for platinum-sensitive recurrent ovarian cancer with rising CA125 and no evidence of clinical or RECIST progression: A GINECO randomized phase II trial (REGOVAR).

Objective: To evaluate the efficacy and safety of regorafenib versus tamoxifen in platinum-sensitive ovarian cancer biological recurrence, defined by CA-125 increase without radiological (RECIST criteria) or symptomatic evidence of progression.

Patients And Methods: 116 patients with platinum-sensitive ovarian cancer presenting an isolated increase of CA-125 were planned to be randomized. Regorafenib was administered orally at 160 or 120 mg daily, 3 weeks on/1 week off or tamoxifen at 40 mg daily, until disease progression or development of unacceptable toxicity. The primary endpoint was Progression-Free Survival, assessed by progression according to RECIST 1.1 or death (by any cause). Secondary endpoints included Overall Survival, Best Response and CA-125 response rate.

Results: 68 patients were randomized. Median age was 67 years (range: 30-87). Primary site of cancer was ovarian for most patients (92.6%). Tumors were predominantly serous / (89.7%), high grade (83.6%) and initial FIGO staging was III for 69.6% of the patients. Most (79.4%) patients were included after the first line of platinum-based treatment. After a median follow-up of 32 months, there was no difference of progression-free survival (PFS) between regorafenib and tamoxifen groups (p = 0.72), with median PFS of 5.6 months (CI 90%: 3.84-7.52) for the tamoxifen arm and 4.6 months (CI 90%: 3.65-7.33) for the regorafenib arm. There was also no difference in term of overall survival, best response or CA-125 response, delay to next therapy. Regorafenib presented a less favorable safety profile than tamoxifen, with grade 3/4 events occurring for 90.9% of the patients compared to 54.3% for tamoxifen. The most frequent were cutaneous, digestive, and biological events. Notably, hand-foot syndrome occurred in 36.4% of these patients.

Conclusion: Regorafenib presented an unfavorable toxicity profile compared to tamoxifen, with no superior efficacy in this population of patients.