Modeling the risks and benefits
Identifying a possible excess of NTDs with dolutegravir treatment in adolescent girls and young women doesn’t, of course, tell the whole risk-benefit story for dolutegravir and possibly the other INSTIs. Caitlin Dugdale, MD, an infectious diseases physician at Massachusetts General Hospital in Boston, reported a model she developed to better define the pluses and minuses of dolutegravir treatment, compared with efavirenz. The model used projections for women in South Africa of child-bearing potential infected by HIV over the next 5 years and used data on drug efficacy and harms based on published reports. For example, the ability of the two drugs to produce undetectable viral loads was assumed by the model to be 94% after 48 weeks on treatment with dolutegravir and 86% with efavirenz, based on the rates reported in the phase 3, randomized comparison of dolutegravir- and efavirenz-based regimens in the SINGLE trial, with adjustments for factors such as protocol deviations and mortality that were accounted for in other parts of the model, Dr. Dugdale said. She used estimates for NTD incidence based on the published numbers reported by Dr. Zash.
Mitchel L. Zoler/MDedge News
Dr. Caitlin Dugdale
The results showed that, over the next 5 years, based on just the existing and projected rates of HIV infection, treating all infected women and children with a dolutegravir-based regimen instead of a regimen anchored by efavirenz would result in the benefits of 28,400 fewer deaths among women, 52,800 fewer sexual transmissions of HIV, 5,000 fewer pediatric HIV transmissions, and 1,600 fewer pediatric deaths unrelated to an NTD. On the minus side relying on dolutegravir instead of efavirenz was projected to cause an excess of 10,000 neonates born with an NTD, 8,400 excess pediatric deaths, and overall 5,400 fewer children alive and free from HIV. These projections were based on 3.5 million women on first-line treatment with antiretroviral therapy and 1.1 million children born with HIV exposure.
Dr. Dugdale drew particular attention to the comparison between 28,400 fewer deaths among women when treated with dolutegravir at the cost of 8,400 excess pediatric deaths, but cautioned that this creates “a difficult trade-off to balance.” Findings from the model and other information on HIV treatment options should enter into the decision making of each HIV-infected woman who could become pregnant, she said. It’s important that patients view the risks and benefits not just on a population level but on an individual, personal level, Dr. Dugdale said in a video interview. “The individual woman must balance the risks and benefits for herself and her child.”
“Patients need to decide what is important to them,” agreed Dr. Zash during the conference.
Dr. Elaine J. Abrams
The NTD findings also underscored the importance of better contraception options for HIV-infected women. “This is an opportunity to improve reproductive health and contraception for women, especially in resource-poor countries,” commented Elaine J. Abrams, MD, professor of epidemiology and pediatrics at Columbia University in New York, who cochaired the conference session.
Another lesson from the NTD findings is the importance of tracking the safety of new drugs used when women become pregnant and during pregnancy. The dolutegravir arm of the Tsepamo study “was almost by accident,” noted the Georgetown medical ethicist, Dr. Little. “Every new treatment should be examined in pregnant women and infants,” she added. “Studies like this should not be left to chance. Women deserve an evidence base for medication use across the lifespan including during pregnancy and periconception.”
Dr. Little, Ms. Meireles, Dr. Zash, and Dr. Dugdale had no disclosures. Dr. Cahn has been an adviser to or speaker for AbbVie, Merck, and ViiV and has received research funding from AbbVie, Merck, ViiV, and Richmond. Dr. Abrams has been an adviser to Merck and ViiV. Viiv is the company that markets dolutegravir.