Abstract A143: Treatment persistence and rash management of cancer patients treated with epidermal growth factor receptor inhibitors (EGFR-inhs) in Truven Marketscan Research Database
Authors: Chen Lei , Brown Jaqueline , Marmaduke Dale Quentin , Grau Gerrit , Lau Yiu-Keung , Obasaju Coleman K. , Mayo Carlos 
Published: May 2016

EGFR-inhs are treatment options for a number of cancer types and rash toxicity is a common and expected class effect of such treatments. Notably severe rash may lead to treatment discontinuation or dose modification. Although rash management is practiced, it has not been well characterized in the real world setting. The purpose of this study is to describe the management of rash that developed whilst receiving EGFR-inh treatment and how rash affects treatment delivery, using Truven MarketScan Research Database, a US medical claims database.

Adult patients who received treatment of EGFR-inh (EGFR-TKIs or EGFR-mAbs, including Cetuximab, Erlotinib, Gefitinib, Lapatinib, Panitumumab and Vandetanib) during 2004-2012, after diagnosis of tumors approved in the drug labels were identified from the Truven data. The tumors included cancers of the colon, head and neck, lung, breast and thyroid. Occurrence of rash during the on-treatment period was described. Management of rash including treatment and cost was summarized. Demographic, clinical characteristics and EGFR-inh treatment persistence of patients by rash occurrence were described. A total of 22,349 cancer patients with EGFR-inh treatment were identified, of which 22,075 received EGFR-TKIs and 274 received EGFR-mAbs. Of all EGFR-inh treated cancer patients, 9.2% had records of rash during the on-treatment period. Age, gender, tumor type and appearance of secondary cancer had similar distribution among patients with rash and patients without rash. On average, patients with rash had longer treatment duration of EGFR-inh than patients without rash (Mean [Standard Deviation]: 255.1 days [300.6] vs. 125.4 days [154.4] for EGFR-TKIs and 114.5 [91.9] days vs. 78.2 days [75.3] for EGFR-mAbs). Of those who developed rash, most patients (about 70% of the EGFR-TKI treated patients and half of the EGFR-mAb treated patients) were recorded as having rash for only 1 cycle of treatment. In about half of all patients who developed rash, rash first occurred in the 1st cycle of treatment. Approximately 67% of patients with rash received prescription drugs to treat rash. For patients with rash, the average cost per patient for a rash related medical claim was relatively low compared to the average overall cost of treatment per patient ($352 vs. $44,630) during the on-treatment period. As the data source was medical claims, information on over the counter drugs was not available.

The study described the treatment delivery by rash occurrence and the management of rash occurring in a representative population who received EGFR-inh treatment for cancer. Given the nature of medical claims, the recorded rash are likely to be severe conditions that need medical attention, although information on the grade of rash is not available. This may partly explain the relatively low percentage of patients with record of rash occurring during the EGFR-inh on-treatment period, compared to what has been observed in clinical trials. The longer treatment duration of EGFR-inh in patients with rash compared to those without rash may indicate that rash does not affect physicians' and patients' perception of the treatment benefit in a negative way. The results are helpful in understanding the benefit of rash management of EGFR treated cancer patients in the real world.

Citation Format: Lei Chen, Jaqueline Brown, Dale Quentin Marmaduke, Gerrit Grau, Yiu-Keung Lau, Coleman K. Obasaju, Carlos Mayo. Treatment persistence and rash management of cancer patients treated with epidermal growth factor receptor inhibitors (EGFR-inhs) in Truven Marketscan Research Database. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A143.