Background

Use of palbociclib in metastatic breast cancer (MBC) during COVID-19 pandemic period was studied outlining disease course and its impact. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associated disease (COVID-19) established globally this year causing hospital system overload¹ with large influx patients² leading to disruption of routine care³.  Travel restrictions created difficulty for patients⁴. Oral treatment was deemed more appropriate⁴. This led to the developments of rapid guidelines⁵. For a vast majority of ER+/HER2 negative MBC patients, endocrine-based therapy was recommended⁵. The most difficult decision was to add CDK 4/6 inhibitors due to their immunosuppressive effects⁵ although recent major studies have shown genuine advantage of CDK 4/6 inhibitors (Palbociclib, Ribociclib, Abemaciclib)⁶. Main side effects, mainly of Palbociclib and Ribociclib, remained neutropenia⁷ making the decision challanging⁵. 

Method

Retrospective electric database search to describe and analyse clinical use of palbociclib during COVID-19 period from March 2020 till June 2020, compared with non-COVID-19 period at UHNM.

Results

Total 32 patients received palbociclib during COVID-19 period, 75% started with aromatase inhibitor and 25% with Fulvestrant. Mean age 68 years, 50% above 70. Ages and specific sites of disease were comparable; but significant patients had visceral disease during COVID-19. Average numbers of cycles 10. Radiological response seen in 50%, three had disease progression. One had intermediate evidence of COVID-19 infection. No patient had COVID-19 symptoms. Visceral disease was seen in 68% and 80% had mild to moderate co-morbidities. ECOG performance status was 0-2. Starting dose 125 mg daily and first dose reduction (100 mg) done in 20% of patients due to grade 3 neutropenia. Two patients had second dose reduction (75 mg) due to delayed neutropenia after 5 cycles. Cancer antigen 15-3 (CA 15-3) was normal in 40%. Results were compared to non-COVID-19 period.

Conclusion

Patients tolerated palbociclib well during the COVID-19 pandemic without major impact on patients or services. The main side effects of palbociclib remained mild immunosuppression requiring dose modification. Although data is small, still supports use of palbociclib during the COVID-19 pandemic in ER+/ HER2 negative metastatic breast cancer patients in first line or second line settings.

Impact statement

Palbociclib was tolerated extremely well during COVID-19 pandemic.