Learn more about the test for hypersensitivity

Screening for hypersensitivity

Hypersensitivity is an immune-mediated reaction to abacavir that appears to have a genetic basis. Watch this video to learn more about screening patients for hypersensitivity before considering treatment.


 

What are the symptoms of hypersensitivity?

Hypersensitivity to abacavir is clinically defined as a multi-organ syndrome usually characterized by a sign or symptom in 2 or more of the following groups:

Group 1: Fever
Group 2: Rash
Group 3: Gastrointestinal (including nausea, vomiting, diarrhea, or                abdominal pain)
Group 4: Constitutional (including generalized malaise, fatigue, or aches)
Group 5: Respiratory (including dyspnea, cough, or pharyngitis)

If your patient experiences a hypersensitivity reaction, stop treatment with EPZICOM immediately. Symptoms should resolve in a few days. Following a hypersensitivity reaction to abacavir, NEVER restart EPZICOM or any other abacavir-containing product because more severe symptoms can occur within hours and may include life-threatening hypotension and death.

What causes hypersensitivity?

The cause of the hypersensitivity reaction is unknown, but a link between the hypersensitivity reaction and the presence of the HLA-B*5701 allele has been established.

What is HLA-B*5701 screening?

Data suggest that the presence of the HLA-B*5701 allele confers a higher risk of hypersensitivity. Screening for HLA-B*5701 can be done by commercial labs using a blood sample from the patient. If the screening is positive, your patient has a higher risk for developing an abacavir hypersensitivity reaction.

Prior to initiating therapy with abacavir, screening for the HLA-B*5701 allele is recommended; this approach has been found to decrease the risk of hypersensitivity reaction.

Screening is also recommended prior to reinitiation of abacavir in patients of unknown HLA-B*5701 status who have previously tolerated abacavir.

HLA-B*5701 negative patients may develop a suspected hypersensitivity reaction to abacavir; however, this occurs significantly less frequently than in HLA-B*5701 positive patients.

Regardless of HLA-B*5701 status, permanently discontinue abacavir if hypersensitivity cannot be ruled out, even when other diagnoses are possible.

HLA-B*5701 screening for the risk of abacavir hypersensitivity should never substitute for the appropriate clinical vigilance and patient management in individuals undergoing treatment with abacavir-containing products.

HLA-B*5701 screening is not a diagnostic tool, and should not be used to make a clinical diagnosis of hypersensitivity.

Important Safety Information

  • EPZICOM contains abacavir sulfate, which has been associated with serious and sometimes fatal hypersensitivity reactions. Hypersensitivity to abacavir is a multi-organ clinical syndrome usually characterized by a sign or symptom in 2 or more of the following groups: (1) fever, (2) rash, (3) gastrointestinal (including nausea, vomiting, diarrhea, or abdominal pain), (4) constitutional (including generalized malaise, fatigue, or achiness), and (5) respiratory (including dyspnea, cough, or pharyngitis). Discontinue EPZICOM as soon as a hypersensitivity reaction is suspected.

Indication and Usage

  • EPZICOM, in combination with other antiretroviral agents, is indicated for the treatment of HIV-1 infection. EPZICOM is one of multiple products containing abacavir
  • Before starting EPZICOM, review medical history for prior exposure to any abacavir-containing product in order to avoid reintroduction in a patient with a history of hypersensitivity to abacavir. In one controlled study, more patients taking abacavir 600 mg once daily had severe hypersensitivity reactions compared to patients taking abacavir 300 mg twice daily
  • It is not recommended that EPZICOM be used as a component of a triple-nucleoside regimen

  • Patients who carry the HLA-B*5701 allele are
    at high risk for experiencing a hypersensitivity
    reaction to abacavir. Prior to initiating therapy with abacavir, screening for the HLA-B*5701 allele is recommended; this approach has been found to decrease the risk of hypersensitivity reaction. Screening is also recommended prior to reinitiation of abacavir in patients of unknown HLA-B*5701 status who have previously tolerated abacavir. HLA-B*5701 negative patients may develop a suspected hypersensitivity reaction to abacavir; however, this occurs significantly less frequently than in HLA-B*5701 positive patients. Regardless of HLA-B*5701 status, permanently discontinue EPZICOM if hypersensitivity cannot be ruled out, even when other diagnoses are possible
  • In any patient treated with abacavir, the clinical diagnosis of hypersensitivity reaction must remain the basis of clinical decision making
  • Following a hypersensitivity reaction to abacavir, NEVER restart EPZICOM or any other abacavir-containing product because more severe symptoms can occur within hours and may include life-threatening hypotension and death
  • Reintroduction of EPZICOM or any other abacavir-containing product, even in patients who have no identified history or unrecognized symptoms of hypersensitivity to abacavir therapy, can result in serious or fatal hypersensitivity reactions. Such reactions can occur within hours
  • Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination, including abacavir, lamivudine, and other antiretrovirals
  • EPZICOM Tablets are contraindicated in patients with hepatic impairment
  • Severe acute exacerbations of hepatitis B have been reported in patients who are coinfected with hepatitis B virus (HBV) and HIV and have discontinued lamivudine, which is one component of EPZICOM. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who discontinue EPZICOM and are coinfected with HIV and HBV. If appropriate, initiation of anti-hepatitis B therapy may be warranted
  • Hepatic decompensation (some fatal) has occurred in HIV/HCV coinfected patients receiving combination antiretroviral therapy for HIV and interferon with or without ribavirin. Patients receiving interferon with or without ribavirin and EPZICOM should be closely monitored for treatment-associated toxicities, especially hepatic decompensation. Discontinuation of EPZICOM should be considered as medically appropriate
  • Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including EPZICOM. During the initial phase of combination antiretroviral treatment, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia [PCP], or tuberculosis), which may necessitate further evaluation and treatment
  • Redistribution/accumulation of body fat has been observed in patients receiving antiretroviral therapy. The causal relationship, mechanism, and long-term consequences of these events are currently unknown
  • The underlying risk of coronary heart disease should be considered when prescribing antiretroviral therapies, including abacavir, and action taken to minimize all modifiable risk factors (eg, hypertension, hyperlipidemia, diabetes mellitus, and smoking)
  • In one study of therapy-naive patients (CNA30021), the most common adverse events (grade 2-4) reported with abacavir and lamivudine dosed once daily were hypersensitivity (9%), insomnia (7%), depression (7%), headache/migraine (7%), fatigue (6%), dizziness (6%), nausea (5%), diarrhea (5%), rash (5%), pyrexia (5%), abdominal pain (4%), abnormal dreams (4%), and anxiety (3%)