19556 Background: Rash develops in approximately 90% of patients (pts) treated with epidermal growth factor receptor inhibitors (EGFRIs) E and C, leading to significant physical/psychosocial discomfort and inconsistent therapy. This study characterizes outcomes of a rash management algorithm developed in the multidisciplinary dermatology-oncology SERIES clinic. Methods: Retrospective chart analysis was performed of pts with E and C rashes (n=45) who were treated with: oral tetracyclines (doxycycline or minocycline) bid and topical calcineurin inhibitors (pimecrolimus/ tacrolimus) or corticosteroids bid. After a baseline visit, pts were assessed at 2–4 week intervals and CTC graded (G). Management data, skin biopsies and photographs were evaluated. Response was defined as: Complete Response (CR) = severity decrease (decr) by 2G, Partial Response (PR) = 1G decr, Stable Disease (SD) = no G change, and Progressive Disease (PD) = increase by = 1G. Best response (BR) was defined as the patient’s best rash outcome at any point in time. Results: 43 out of 45 pts had evaluable data. Of 27 women and 16 men, mean age = 60 yrs (range 34–88), 60% received E and 40% C. For BR, 51% of patients had a CR, 42% had PR, 7% had SD, and 0% had PD. Age was related to BR (p=0.036), with median ages (in years) of 66, 57.5 and 48 for 22, 18 and 3 pts with CR, PR and SD respectively. BR was related to grade (p=0.045), with CR in 69% of G1 pts, 35% in G2 pts, and 54% in G3 pts. BR was not related to E or C (p=0.40). Dose modification was required in 8% (E) and 22% (C) and dose discontinuation in 0% (E) and 17% (C) pts. Conclusions: SERIES algorithm rash management demonstrates that combined oral tetracyclines, topical calcineurin inhibitors and corticosteroids result in improvement in a majority of subjects. The greater rate of dose modification/discontinuation with C supports the need for proactive/early intervention. Trials are underway to evaluate prophylactic therapies against rash to EGFRIs. No significant financial relationships to disclose.