Investigators modeled what a long-acting injectable HIV prevention medication would have to cost in order for it to be justified when compared to generic, oral PrEP for HIV patients and transmission prevention.
The efficacy of cabotegravir (CAB-LA), a long-acting injectable HIV prevention medication, is superior to oral medication but the higher price needs to be justified, according to a paper published in Annals of Internal Medicine.
Investigators from Massachusetts General Hospital employed a simulation model using different willingness-to-pay threshold categories in order to identify the greatest possible price differential that American society should accept for the additional benefits of CAB-LA over oral PrEP among men who have sex with men and transgender women (MSM/TGW). The study authors used daily oral emtricitabine/tenofovir disoproxil fumarate (F/TDF) and branded emtricitabine–tenofovir alafenamide (F/TAF), as their PrEP in the model.
The study authors wrote that an unblinded, international trial of CAB-LA compared to oral PrEP demonstrated a reduction in HIV infections among the CAB-LA group, with similar results in a U.S.-based subset. These study results, and the fact that the cost of drugs and administration with CAB-LA remained unknown, prompted the investigators to evaluate the possibility of drug resistance among those prescribed PrEP.
The 10-year, 4-strategy model included no PrEP use, use of F/TDF, use of F/TAF, and use of CAB-LA and modeled the clinical benefits, including primary transmissions; quality-adjusted life-years (QALY), and mortality, the study authors explained. They also included the costs of HIV care and PrEP and incremental cost-effectiveness ratios to determine the highest price that CAB-LA could command. With this known, they determined that the QALY threshold would vary from $50,000 to $300,000 per QALY.
Total primary transmissions were ultimately higher among the no PrEP mode, lower for F/TDF and F/TAF, and lowest for CAB-LA, the study authors observed. They also said averted HIV infections and primary transmissions produced the highest QALY for CAB-LA.
Study author Anne Neilan, MD, MPH, investigator in the MGH Divisions of General Academic Pediatrics and Infectious Diseases, told Contagion that oral PrEP costs about $1/day, or $360/year, which in turn meant that CAB-LA priced at $20,000 could not be considered to provide a good value.
Costs over 10 years would total $33.48 billion for no PrEP, about $30 billion for generic F/TDF, about $60 billion for F/TAF, and when assuming the upper boundary for the CAB-LA price point, $75 billion, the study authors found.
Assuming the thresholds for QALY and CAB-LA, the maximum price premium for CAB-LA would be between $3000 and $6600, meaning the CAB-LA price would be $3400 to $7000, the study authors said, when priced to be cost-saving against F/TDF. For CAB-LA to be priced as cost-saving compared to F/TAF, the price would have to be about $2300, the study authors said.
“It’s a remarkable advancement that HIV can now be prevented with one pill, once a day, for $1 a day, and treated, also with one pill, once a day,” Neilan continued. “The key issue is to make sure that all adults, young and old, get tested for HIV, to incorporate PrEP into routine discussions about sexual health, and to prescribe PrEP for who are at increased HIV risk, or antiretroviral therapy if they have HIV. That is how we can end the HIV epidemic in the United States and elsewhere.”