Treatment duration as a function of clinician‐level patient volume: mechlorethamine treatment for mycosis fungoides cutaneous T‐cell lymphoma (MF‐CTCL)

Treatment duration as a function of clinician‐level patient volume: mechlorethamine treatment for mycosis fungoides cutaneous T‐cell lymphoma (MF‐CTCL)

Christiane Querfeld1, Theresa Pacheco2, Bradley Haverkos2, Gary Binder3, James Angello3, Brian Poligone4

1City of Hope Comprehensive Cancer Center, Duarte, CA, USA; 2University of Colorado, Denver, CO, USA; 3Helsinn Therapeutics US, Inc.; 4Rochester Skin Lymphoma Medical Group

Purpose of the Study: Guidelines recommend skin‐directed therapies for early‐stage MF‐CTCL, including topical mechlorethamine. Mechlorethamine yields high response rates, particularly with treatment >3 months (Lessin, 2013); earlier discontinuation is often attributed to dermatitis. We evaluated the association of patient volume with early discontinuation and overall treatment duration for clinicians prescribing standardized 0.016% gel formulation mechlorethamine.

Summarized Description of the Project: We evaluated dispensing records 10/2013‐4/2019 (each dispense was typically a one‐month supply). For each prescriber we calculated the mean quantity of dispenses per patient. We excluded patients on treatment 100 days of data cutoff if they had < 6 cumulative dispenses. We assigned patients with 4 prescribers to the treating institution, and those prescriber's other patients if 4. Kruskal‐Wallis significance testing was performed on clinician clusters and logistic regression on early discontinuation.

Results: We assigned 4922 patients to 2004 clinicians. The 52 clinicians with >15 patients (mean 41.3) treated 44% of total patients, with 6.3 median dispenses/patient. 128 clinicians with 5‐15 patients had 4.3 median dispenses and the interquartile range was 6.625‐3.325. As volume further declined, variability and early discontinuation increased; 1348 clinicians with a single patient had two median dispenses, with 33% having only one dispense (p < 0.0001). Early discontinuation was significantly associated with lower volume (OR 0.80; CI 0.754‐0.842).

Conclusion: Individual clinicians prescribing mechlorethamine 0.016% gel for MF‐CTCL varied considerably in patient volume and treatment duration. Clinicians with higher patient volume consistently sustained longer treatment duration and, importantly, avoided early discontinuation, perhaps attributable to experience managing the condition and dermatitis, and setting patient expectations for treatment adherence and toxicity.

References

Lessin S et. al., Topical Chemotherapy in Cutaneous T‐cell Lymphoma, Arch Dematol, 2012