Recently, pharmaceutical companies have developed various biological agents for the treatment of inflammatory diseases.
With more treatment options available other than the conventional tumor necrosis factor-alpha (TNF-α) inhibitors, the risk of developing tuberculosis has emerged as a major concern in the use of biological medicines.
Experts say using TNF-α inhibitors for the first-line treatment unconditionally, despite their higher TB risk, is not appropriate anymore.
It is nothing new that TNF-α inhibitors have been shown to raise the risk of developing TB.
The 2017 TB treatment guideline released by the Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) and the Korea Centers for Disease Control and Prevention (KCDC) states, “Patients who are scheduled to receive treatment using TNF antagonists must be tested for active TB and latent TB infection (LTBI).”
The guideline notes that even though three TNF-α inhibitors – infliximab, adalimumab, and etanercept – are used for various inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, and Crohn’s disease, they have a major safety issue regarding increasing opportunistic infectious diseases including TB.
If an ankylosing spondylitis patient developed TB during TNF-α inhibitor treatment in the past when there was no other option, physicians would either switch to safer etanercept or continue the TNF-α inhibitor therapy after treating TB, according to Lee Sang-hoon, a professor of rheumatology at Kyunghee University Hospital at Gangdong.
“But if TB recurs repeatedly, the lungs can be severely damaged. Nowadays, some countries recommend replacing TNF-α inhibitors with newly developed interleukin-17A inhibitors for patients with TB or poor lung functions,” he said.
Korea allows other biological agents including interleukin inhibitors only when TNF-α inhibitor treatment fails.
Lee noted that there was no patient who had a higher TB infection risk after using interleukin-17A inhibitors.
Recommending TNF-α inhibitors among biological drugs is rational because they have demonstrated the safety and efficacy for a long time.
Moreover, new biological medicines are expensive. Unless they get insurance benefits, it is not easy for physicians or patients to choose them.
Considering the limited finance for national health insurance, the government would do better to help physicians use expensive drugs appropriately in terms of cost-effectiveness. At the same time, the government should find a tool to ensure safety for patients.
Such a tool should reflect doctors’ medical views on TB risk in the use of biological drugs.
Korea has the highest TB incidence and TB-related mortality rate among the Organization for Economic Cooperation and Development.
According to the KCDC, 33.2 percent of Koreans are infected with latent TB. The agency aims to reduce the TB incidence to 40 per 100,000 people by 2022 and completely eradicate the disease by 2035.
To meet the goals, and to curb the rising TB risk amid the increase of TNF-α inhibitors, the government needs to make a wise decision.