YO17 - Serous ovarian cancer treated with palbociclib and letrozole

Case summary

Serous ovarian cancer accounts for 80% of ovarian cancer, most of them being high grade and the expected survival for recurrent disease is less than 12 months. CDK4/6 inhibitor has shown promising benefit in ER-positive metastatic breast cancer. A phase II trial showed that investigating palbociclib in recurrent ovarian cancer has shown tolerable toxicity profile and radiological median PFS of 3.7 months and Gynecologic Cancer InterGroup CA125 criteria median PFS of 4.0 months. Therefore CDK4/6 inhibitors used alone or as combination could be useful in recurrent ovarian cancer. We report a case of recurrent ovarian cancer treated with palbociclib and letrozole.

Madam X was initially diagnosed with stage 3 ovarian cancer in 1994 at 25-years-old. She underwent TAHBSO, infracolic omentectomy followed by adjuvant carboplatin/paclitaxel. She was disease-free for 19 years until 2013 when she presented with pleural effusion which was confirmed to be recurrent papillary serous carcinoma. She received carboplatin/paclitaxel/bevacizumab combination for 8 months and stopped in view that the patient opted for a drug holiday. In 2016, her pleural effusion worsened. BRCA testing showed no BRCA1/2 mutation. She was then treated with carboplatin & pegylated liposomal doxorubicin for 6 cycles.

In April 2017, she presented with left axillary lymphadenopathy. Core biopsy showed high-grade serous carcinoma, positive for ER & PR; negative for HER2, PDL1 and MSI. She was then commenced on letrozole.

In May 2017, her CA15-3 was increasing from 55U/mL to 77U/mL, and letrozole was changed to tamoxifen. However, CA15-3 continued to rise to 113U/mL within a month. Her performance status was ECOG 0. She was then commenced on palbociclib 125mg OD 3 weeks on and 1 week off schedule with letrozole 2.5mg OD since June 2017. She tolerated palbociclib well and did not require any dose adjustments. The adverse events reported were grade 2 leucopenia and grade 2 neutropenia. CA 15-3 remained to respond for 14 months and she is still ongoing treatment.

In this case, palbociclib and letrozole have shown a prolonged PFS of more than 14 months and an excellent toxicity profile. This could present a potential therapeutic role of CDK4/6 inhibition in recurrent ovarian cancers.

Clinical trial identification

Editorial acknowledgement