Association Between the Number of Suppliers for Critical Antineoplastics and Drug Shortages: Implications for Future Drug Shortages and Treatment

Purpose: Congress has identified the critical need to evaluate contributors to ongoing cancer drug shortages. Because increased competition may reduce drug shortages, we investigated the association between the number of suppliers for first-line breast, colon, and lung antineoplastics and drug shortages.

Data and methods: Using the 2003 to 2014 Red Book and national drug shortage data from the University of Utah's Drug Information Service, we used exploratory analysis to quantify time trends in first-line drug suppliers and shortages by cancer site. Generalized mixed models were used to examine the association between the number of suppliers for individual drugs and resulting drug shortages.

Results: Among 35 antineoplastic drugs approved for first-line treatment of breast, colon, and lung cancer, the number of unique suppliers varied greatly (range, 1 to 19). In 2003, 12.5%,33.3%, and 0%of breast, colon, and lung cancer drugs, respectively, experienced shortages, which increased overall by 2014, to 40.0%, 37.5%, and 54.5%, respectively. Having as mall number of drug suppliers more than doubled the odds of shortages compared with a large number of suppliers (≥5), although the results were only statistically significant with three to four suppliers (odds ratio = 2.6, P = .049) but not with one to two suppliers (odds ratio = 3.49, P = .105). One of the strongest risk factors for drug shortages was the age of the drug, with older drugs significantly more likely to experience shortages (P<.001).

Conclusion: Cancer drugs with a small number of suppliers had a higher risk of drug shortages than did those with$5 suppliers, but the relationship was nonlinear. Because the age of the drug is the strongest risk factor, future studies should explore underlying causes of shortages in older drugs.