CAB-LA Cost Might Be a Deal-Breaker for Payers and Patients

Liz Scherer

February 02, 2022

What happens when the benefits of innovations in treatment and care delivery don't outweigh their costs? At what point do advances become too expensive to justify their utility, despite signs that they have the ability to move the envelope closer toward ending an epidemic or delivering a much needed option to the most vulnerable populations?  

The HIV community is about to find out.

Findings of a newly-published analysis in the Annals of Internal Medicine suggest that despite its clinical advantages, the maximum price premium — the greatest possible price differential that society should be willing to pay for long-acting, injectable cabotegravir (CAB-LA) for pre-exposure prophylaxis (PrEP)  — might be above and beyond the ante that payers, HIV practitioners, and patients are willing, or more importantly able, to pay.

Dr Anne Neilan

"We used a computer simulation-based analysis to compare the clinical and economic value of long-acting injectable PrEP to tenofovir-based PrEP, and what we found among men who have sex with men (MSM) and transgender women (TGW) at increased risk for HIV, that CAB-LA would provide good value for its money [only] if  its annual price was less than $6600 higher than the oral formulations," Anne Neilan, MD, MPH, lead author and infectious disease specialist at Massachusetts General Hospital in Boston, told Medscape Medical News

Neilan noted that shortly after the paper was accepted for publication, CAB-LA's annual price was announced: $22,200. In comparison, oral generic emtricitabine-tenofovir disoproxil fumarate (F/TDF) costs roughly $360 annually, and branded emtricitabine-tenofovir alafenamide (F/TAF), $16,800.

CAB-LA Price Differential vs Oral Tenofovir-based PrEP Too High

Neilan and colleagues (including CDC Director Rochelle Walensky, MD, named as senior author) used the Cost Effectiveness of Preventing AIDS Complication model (a validated state-transition microsimulation model of HIV prevention and treatment) to run several management scenarios in a very high risk (VHR) population comprising 476,700 MSM and TGW without HIV at entry: 1) no PrEP, 2) generic F/TDF; 3) branded F/TAF; and 4) CAB-LA. 

The research team projected clinical benefits/outcomes (ie, primary transmissions, quality-adjusted life-years [QALYs)] and mortality), as well as healthcare sector factors (HIV and PrEP drug and facility costs), and incremental cost-effectiveness ratios (ICERS). In addition to discounting clinical outcomes and costs at 3% per year, and accounting for potential health and economic benefits realized by averting primary transmission, the researchers used a commonly-accepted threshold of $50,000 to $300,000 per QALY to represent the greatest possible price differential that society should be willing to accept for CAB-LA over oral PrEP.

The findings showed that at 10 years, total primary transmissions in the VHR group were highest for no PrEP (n = 178,000) and lowest for CAB-LA (n = 107,000). This translated into the highest QALYS for CAB-LA (n = 4,654,000), and an increased life expectancy of 26,000 QALYs compared with branded F/TAF (n = 4,628,000). By further comparison, F-TAF was shown to increase life expectancy by 2000 QALYs over generic F/TDF as a result of the latter's associated bone and renal toxicities. 

Additionally, based on a 90% efficacy and a 42% retention rate at 6 years, the maximum premium price at which CAB-LA would be considered cost-effective would range from $1800 to $5200 over branded F/TAF (CAB-LA price $18,000 to $22,000), with an ICER of ≤100,000 QALYs.

"It's often the case that a particular intervention that provides more clinical benefits is more expensive than its alternatives," explained Nieman. "What was interesting in this analysis is whichever the 'willingness-to-pay threshold' you choose, the finding remains that given the availability of a highly effective alternative, oral PrEP, we are constrained in our willingness (or payers' willingness) to pay for the incremental benefit of CAB-LA," she said.

An Ounce of Prevention, a Pound of Cure

The study highlighted that for MSM/TGW at very high risk for HIV, any PrEP strategy would provide substantial clinical improvements, prolong life, reduce onward transmissions, and reduce antiretroviral therapy costs over time. However, the findings also unintentionally point to a darker side of prevention: today, the responsibility for paying for PrEP remains almost solely on the shoulders of patients — the very same patients who are unlikely to have the means or ability to do so.

Dr Lina Rosengren-Hovee

"We rely on a ton of federal programs like Ryan White for the provision of antiretroviral therapy, but PrEP is unsupported," Lina Rosengren-Hovee, MD, MPH, assistant professor of medicine at University of North Carolina School of Medicine in Chapel Hill and an HIV provider (who was not involved in the study) told Medscape.  

"This feeds into bigger systemic issues of where funding comes from for PrEP; it's just a snowball issue for the people who are most marginalized, who already have the least amount of access," she said. "Without those government programs in place, I don't think that we [can] sustain innovation in further PrEP modalities. 

Neilan does not disagree but remains more hopeful. "CAB-LA is likely to have the greatest utility and benefit among people who cannot engage in PrEP for whatever reason," she said. "My hope is that by detailing the maximum price premium that we should be willing to pay for this novel option, we can inform the discussion around how these incredible therapies are priced so that they can be priced in a way that will permit them to be accessible to those who need it most."

The study was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; the National Institute of Allergy and Infectious Diseases; the National Heart, Lung, and Blood Institute; the National Institute on Drug Abuse, the Jerome and Celia Reich HIV Scholar Award, and the Steve and Deborah Gorlin MGH Research Scholars Award. Neilan and Rosengren-Hovee have disclosed no relevant financial relationships. The full list of author disclosures can be found here.

Ann Intern Med. Published online January 31, 2022. Abstract, Editorial

Liz Scherer is an independent journalist specializing in infectious and emerging diseases, cannabinoid therapeutics, neurology, oncology, and women's health.

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