What labs should be ordered prior to initiating a patient on Sunlenca (Lenacapavir) and Cabotegravir injection, aside from confirming Human Immunodeficiency Virus (HIV) infection?

Required Laboratory Tests Prior to Initiating Sunlenca and Cabotegravir Injection

Prior to initiating Sunlenca (Lenacapavir) and Cabotegravir injection, comprehensive laboratory testing is essential to ensure safety and efficacy, including HIV confirmation, renal function, liver function, and screening for coinfections.

Essential Laboratory Tests

• Combined HIV antibody and antigen testing - Confirmation of HIV status using a test approved by the FDA for diagnosis of acute or primary HIV infection is mandatory 1, 2
• HIV RNA level - Required if there is clinical suspicion of acute HIV, as PrEP/treatment should not be initiated until HIV RNA test results confirm uninfected status 1, 2
• Serum creatinine level and estimated glomerular filtration rate (eGFR) - Essential to assess kidney function before initiating these medications 1
• Complete blood count with differential - Provides baseline information necessary before initiating therapeutic agents that may have myelosuppressive effects 1
• Comprehensive chemistry panel - Assesses liver function and electrolyte balance 1, 3

Hepatitis Screening

• Hepatitis B surface antigen (HBsAg) - Critical as discontinuation of therapy in patients with active HBV could lead to acute flares or hepatic decompensation 1
• Hepatitis C IgG antibody - If not known to be previously positive; if known positive, hepatitis C virus RNA should be confirmed 1
• Hepatitis A IgG antibody - Particularly important for men who have sex with men (MSM) and people who inject drugs if immune status is unknown 1

Additional Important Tests

• Fasting lipid profile - Many antiretroviral drugs and HIV infection itself are associated with increased cholesterol and triglyceride levels 1, 3
• Urinalysis - To screen for proteinuria and assess baseline renal function 1
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency screening - Recommended for patients with predisposing racial or ethnic backgrounds before starting therapy with oxidant drugs 1
• HLA-B*5701 testing - If abacavir is being considered as part of the regimen 1

Sexually Transmitted Infection Screening

• Genital and nongenital Neisseria gonorrhea and Chlamydia trachomatis testing by nucleic acid amplification test (NAAT) 1
• Syphilis testing - Particularly important in high-risk populations 1

Special Considerations for Lenacapavir (Sunlenca)

• HIV resistance testing - Particularly important when transitioning from other regimens to ensure no pre-existing resistance that might compromise treatment efficacy 2, 4
• Pregnancy testing - For individuals of childbearing potential 1

Special Considerations for Cabotegravir

• Baseline integrase resistance testing - Particularly if there is a history of integrase inhibitor exposure 5, 6
• Screening for L74I integrase polymorphism - Especially in patients with HIV-1 subtype A1, as this is associated with increased risk of virologic failure 5
• Archived NNRTI resistance testing - If available, as presence of archived NNRTI resistance-associated substitutions has been associated with higher virologic failure rates 5

Important Monitoring Considerations

• Follow-up testing should be scheduled appropriately after initiation:
  • HIV testing at 1 month and then quarterly 1
  • Renal function monitoring at first quarterly visit and then annually (more frequently for patients at risk for kidney injury) 1
  • STI screening quarterly 1

Common Pitfalls to Avoid

• Failing to confirm HIV status with appropriate testing - Using only rapid tests without confirmatory RNA testing when indicated can lead to development of resistance if PrEP is started in an infected individual 2, 1
• Overlooking hepatitis B status - Critical as discontinuation of therapy in patients with active HBV could lead to serious hepatic complications 1
• Inadequate assessment of renal function - Both medications require baseline renal function assessment 1
• Missing resistance testing - Particularly important when transitioning from other regimens to ensure no pre-existing resistance 5, 7

By ensuring comprehensive laboratory assessment before initiating Sunlenca and Cabotegravir injection, clinicians can optimize treatment efficacy and minimize potential adverse effects, ultimately improving patient outcomes.