HLA Screening in Reducing the Risk of Antiepileptic Drug-induced Cutaneous Adverse Reactions


Original post, click here

Cutaneous adverse drug reactions (cADRs) include mild maculopapular exanthema (MPE) and severe cutaneous reactions such as hypersensitivity syndrome, Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). cADRs are considered as a major public health issue because of their potentially life-threatening morbidity, especially severe cutaneous reactions. The incidence of SJS/TEN is estimated to vary from 1 in 1,000 to 10,000 drug exposures, and its mortality is as high as 35%. Antiepileptic drugs (AEDs), particularly those with aromatic ring structures such as carbamazepine (CBZ), lamotrigine (LTG), and phenytoin (PHT), are among the most common causes of severe cutaneous reactions. The incidence of AED-induced SJS was estimated as 0.2% and all cases occurred in individuals receiving aromatic AEDs.

Previous studies have validated that the human leukocyte antigen (HLA) allele HLA-B*15:02 is strongly associated with CBZ-induced SJS/TEN in southern Han Chinese and populations in southeast Asia. Our recent studies indicated that HLA-A*24:02 is a common genetic risk factor for CBZ-, LTG-, and PHT-induced SJS/TEN. It is also associated with MPE. Additionally, another four alleles, including HLA-B*15:01, HLA-B*15:11, HLA-A*02:01,and HLA-DRB1*01:01, were showed to be potential risk factors for aromatic AEDs-induced SJS/TEN. In 2007, the US Food and Drug Administration issued the safety alert that recommended HLA-B*15:02 screening for people with Asian ancestry before starting CBZ, and avoidance of the drug if the test is positive. Subsequent studies from Taiwan, Hong Kong and Thailand demonstrated that HLA-B*15:02 screening before commencing CBZ can significantly reduce the incidence of CBZ-induced SJS/TEN. However, the overall incidence of AEDs-induced SJS/TEN remained unchanged in Hong Kong, as PHT-induced SJS/TEN increased when CBZ-SJS/TEN decreased. Moreover, no study focuses on the incidences of AEDs-induced cADRs with and without HLA screening before commencing aromatic AEDs. Therefore, we are planning to conduct a multicenter prospective study to examine the reduction of AEDs-induced cADRs after the HLA screening prior to the beginning of aromatic AEDs administration.

Primary Outcome Measures:

Estimated Enrollment: 4000
Anticipated Study Start Date: July 2017
Estimated Study Completion Date: June 2021
Estimated Primary Completion Date: June 2021 (Final data collection date for primary outcome measure)
Experimental: Group with two strong risk factors

When HLA screening before commencing aromatic AEDs shows positive for both HLA-A*24:02 and HLA-B*15:02 in a patient, aromatic AEDs were not administrated for this patient.

Diagnostic Test: HLA screening before commencing aromatic AEDs

When the risk HLA alleles are tested positive for the patients, aromatic AEDs were avoided or administrated with caution according to the risk level.

Experimental: Group with one strong risk factors

When HLA screening before commencing aromatic AEDs shows positive for HLA-B*15:02, carbamazepine (CBZ) was not administrated, and other aromatic AEDs were prescribed with caution or avoided if alternative non-aromatic AEDs can be prescribed instead.

When HLA screening before commencing aromatic AEDs shows positive for HLA-B*15:01 or HLA-A*24:02, aromatic AEDs were prescribed with caution or avoided if alternative non-aromatic AEDs can be prescribed instead.

Diagnostic Test: HLA screening before commencing aromatic AEDs

When the risk HLA alleles are tested positive for the patients, aromatic AEDs were avoided or administrated with caution according to the risk level.

Experimental: Group with one potential risk factors

When HLA screening before commencing aromatic AEDs shows positive for any potential risk allele such as HLA-B*15:11, HLA-A*02:01and HLA-DRB1*01:01, aromatic AEDs were prescribed with caution or avoided if alternative non-aromatic AEDs can be prescribed instead.

Diagnostic Test: HLA screening before commencing aromatic AEDs

When the risk HLA alleles are tested positive for the patients, aromatic AEDs were avoided or administrated with caution according to the risk level.

Experimental: Group without known risk factors

When HLA screening before commencing aromatic AEDs shows negative for any known HLA risk allele , aromatic AEDs was administrated to these patients.

Diagnostic Test: HLA screening before commencing aromatic AEDs

When the risk HLA alleles are tested positive for the patients, aromatic AEDs were avoided or administrated with caution according to the risk level.

In this prospective study, anticipant 4000 or more patients from multicenters in southern China will be recruited. A HLA screening will be conducted before these patients start aromatic AEDs treatments. According to the HLA genotype, these patients will be divided into four groups that are three positive groups with different risk alleles and one negative group with no known risk allele. Aromatic AEDs were avoided or administrated with caution according to the risk level in the three positive groups, while they can be prescribed in the negative group. The effectiveness of HLA screening prior to the beginning of aromatic AEDs administration will be observed by the reduction of overall incidence of AEDs-induced cADRs.