Introduction: Achieving and maintaining testosterone(T) suppression to castrate levels is the cornerstone of androgen deprivation therapy(ADT) in advanced prostate cancer(PCa). However, T may rise above castrate level(50 or 20ng/dL) between injections, especially if a dose is delayed. PCa patients are unable to self-administer treatment and need a clinic visit for injections. During COVID pandemic, visits should be minimized. 6-month formulations only require two office visits/year, and therefore, only have two opportunities to be ‘late’. We present analyses of PCa patients treated with the 2 most commonly used ADTs. Methods: Analysis(1/1/07-6/30/16) of US oncology/urology electronic medical records of PCa patients who received leuprolide acetate(LA): in situ gel technology(Gel-LA, subcutaneous) or microsphere technology(Msphere-LA, intramuscular). Mean late doses/ year for 1,3,4,6-month LHRH agonist formulations were calculated. Late dose was defined as occurring after days 33,98,129,195, respectively. Mean T and rate of T-tests >50 and 20ng/dL were evaluated. Results: Mean late doses/year for 1,3,4,6-month LHRH agonists formulations were 5.4,0.8,0.8,0.6, respectively. With late dosing, mean T was 48ng/dL(6-month Gel-LA) vs. 76ng/dL(6-month Msphere-LA). 18%(6-month Gel-LA) vs. 25%(6-month Msphere-LA) of T values were >50ng/dL, and 34%(Gel-LA) vs. 44%(Msphere-LA) of T values were >20ng/dL. All three analyses were statistically significant(p<0.05). Conclusion: 6-month formulations had the least late doses/year vs.1,3,4-month formulations. Of 6-month formulations, when doses were late, subcutaneous Gel-LA had a significantly lower mean T and percent of T-tests >50 and 20ng/dL than intramuscular Msphere-LA. Clinicians should consider using 6-month formulations that demonstrate/ maintain efficacy through the end of the labeled dosing interval.
Hafron JM, Atkinson SN, Boldt-Houle DM, Harris RG. 6-month LHRH formulations are an optimal choice during the COVID-19 pandemic. Paper presented at: The 95th Annual Meeting of the North Central Section of the AUA; 2021 Oct 6-9; Chicago, IL. Available at: https://ncsaua.org/docs/meetings/ncs2110/ncs-2021-program-book.aspx