Abstract B57: Tolerability of pemetrexed: Results from an observational study of second-line treatment of non-small cell lung cancer (NSCLC) among racial groups.
Authors: Adjei Alex , Li Li , Winfree Katherine B. , Pohl Gerhardt , Pennella Eduardo , Girvan Allicia C. , Obasaju Coleman K. , Walker Mark S. , Stepanski Edward J. , Schwartzberg Lee 
Published: August 2014

Background: Second-line treatment with pemetrexed (Pem) has demonstrated safety and efficacy in NSCLC patients. A prospective observational study was conducted to evaluate the impact of race on disease control rate (DCR) in NSCLC patients treated with 2nd line Pem. This analysis focuses on the association of race with tolerability of treatment and patient-reported activities of daily living and symptoms.

Methods: Patients with stage IIIB/IV NSCLC who received at least one dose of Pem for 2nd line treatment were eligible for the study. Tolerability of Pem was evaluated in two ways: reason for discontinuation of treatment and the worst post-baseline patient-reported outcomes (PROs). Treatment duration and reasons for discontinuation between Caucasians (C) and African Americans (AA), Asian Americans (AS), or Hispanics (H) were compared using log-rank and chi-square tests. Two PROs were evaluated: activities of daily living as measured by Older Americans Resource-Services - Instrumental Activities of Daily Living (IADL) and symptom burden as measured by M.D. Anderson Symptom Inventory-Lung Cancer (MDASI-LC). Total IADL score is the sum of seven items (cooking, driving, shopping, doing housework, handling finances, taking medication, talking on telephone) and ranges from 0-14, with higher scores indicating less ability to conduct activities. The MDASI-LC includes 19 items and is scored as four factors: general symptom severity (GSS) subscale, gastrointestinal symptoms, overall distress, and lung cancer related symptoms, with higher scores indicating greater burden. Scores range from 0-10, obtained by averaging individual symptoms. ‘Worst post-baseline’ PRO scores were evaluated and were compared between C and AA, AS, or H using Wilcoxon-Mann-Whitney tests. For robustness, comparisons were also adjusted for predefined covariates (e.g. age, gender, income, insurance, smoking status, ECOG PS, disease stage, histology) using linear regression and least square means (LSM). Analyses were not adjusted for multiplicity; significance level was set at 0.05.

Results: Among 434 eligible patients (n=304 C, 65 AA, 37 AS, 28 H), 61.52% patients stopped treatment due to progression or death; only 9.45% patients stopped treatment due to lack of tolerability. Discontinuation due to lack of tolerability was not significantly different between C and AA, AS, or H, but AS had a significantly longer treatment duration than C (median: 4 vs. 3 cycles, p = 0.02). Post-baseline outcomes were obtained from 75.81% patients, which was comparable across racial groups (range of 74.34% to 82.14%). Among racial groups, baseline PRO scores did not differ significantly. Post-baseline PRO scores did not differ significantly between C and AA or H, but AS reported lower ‘worst post-baseline’ total IADL scores (1.79 vs. 3.12, p=0.02) and GSS scores (2.66 vs. 3.68, p=0.01) than C. After adjusting for covariates, GSS subscale remained significant for AS (LSM difference = -0.97, p=0.01), and AA reported higher GSS (LSM difference = 0.53, p=0.04) and overall distress (LSM difference = 0.85, p=0.02) than C.

Conclusions: Consistent with the literature, Pem is well-tolerated in patients with NSCLC during 2nd line treatment. Generally, few differences in tolerability, activities of daily living, and symptom burden were observed among racial groups.

Citation Format: Alex Adjei, Li Li, Katherine B. Winfree, Gerhardt Pohl, Eduardo Pennella, Allicia C. Girvan, Coleman K. Obasaju, Mark S. Walker, Edward J. Stepanski, Lee Schwartzberg. Tolerability of pemetrexed: Results from an observational study of second-line treatment of non-small cell lung cancer (NSCLC) among racial groups. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr B57.