1607P - The impact of absolute neutrophil count on clinical trial participation in the United States

Background

Neutropenia is most often defined as an absolute neutrophil count (ANC) less than 1.5 K/mcL. This threshold is commonly used in clinical trial eligibility and adverse event grading. Non-Hispanic Blacks in the United States tend to have lower ANCs when compared to other ethnic groups. The current definition of neutropenia may hinder clinical trial participation and undermine therapeutic outcomes in this population.

Methods

Data on ANC was obtained from a nationally representative sample of non-institutionalized Americans who participated in the National Health and Nutrition Examination Survey (NHANES) from 2017 to 2018. Of the 7523 with valid ANC data, participants below the age of 18, those that were pregnant, and those with cancer diagnosis were excluded, leaving a final sample size of 4702. The median ANC and the corresponding 2.5^th and the 97.5^th percentiles for each racial/ethnic group was estimated. The mean ANC between the non-Hispanic Blacks and the other racial/ethnic groups were compared. All analyses incorporated the sampling weights to make national estimates and to account for the differential probability of selection across subjects and nonresponse. The clinicaltrials.gov database was queried for actively recruiting National Institutes of Health (NIH)-funded clinical trials with start dates in 2017 and 2018. The ANC eligibility requirements were obtained from clinical trials that met pre-specified criteria for inclusion in this analysis.

Results

Of the 255 NIH-funded phases 1-3 interventional clinical trials, 172 (67%) required ANCs ≥ 1.5 K/mcL. The median ANC (and the corresponding 2.5^th and 97.5^th centiles) for non-Hispanic Blacks was 3.3 (1.3, 7.7), non-Hispanic Whites 4.2 (1.9, 8.1), and Mexican Americans 4.2 (2.2, 8.4). By using a threshold of 1.5 K/mcL, an estimated 635,550 non-Hispanic Blacks with ANC ≥ 1.3 K/mcL will be classified as having neutropenia. An estimated 226,680 non-Hispanic Blacks that are likely to develop cancer based on their lifetime risk, will be ineligible for clinical trial enrolment because of their ANCs.

Conclusions

Non-Hispanic Blacks have relatively low ANCs; clinical trial eligibility should be revised to improve enrolment in this group.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The author.

Funding

Has not received any funding.

Disclosure

The author has declared no conflicts of interest.