Antiviral & Infectious-Disease Therapeutics

Gilead Sciences has reached an agreement with the Pan American Health Organization to expand access to its twice-yearly HIV-prevention drug lenacapavir across Latin America and the Caribbean, creating a regional procurement pathway for 14 countries including Brazil, Mexico, Argentina, Colombia and Peru that were outside Gilead's existing voluntary generic-licensing arrangements. Availability will still depend on individual countries' regulatory approvals and decisions to adopt the drug. Gilead expects lenacapavir to generate about $1 billion in 2026 sales, and reported 12% year-over-year HIV sales growth in the second quarter of 2026, with Yeztugo sales reaching $232 million, above the $210 million analyst estimate, after which the company raised its expected 2026 HIV-product sales growth to 9%-10%. Reuters reported that new HIV infections in Latin America and the Caribbean rose 13% between 2010 and 2024, and that lenacapavir demonstrated nearly 100% efficacy in large prevention trials, while Yeztugo carries a U.S. annual list price above $28,000. Gilead has already granted royalty-free voluntary licenses to generic manufacturers for resource-limited countries and is still discussing possible local production with Brazil's Health Ministry, so the expanded access may come with lower pricing and margins than in wealthier markets.

Chiome Bioscience announced that the results of joint research with a research group from the Infectious Pathology Division of the National Institute of Infectious Diseases at the National Center for Global Health and Medicine has been published in the international academic journal Protein Science. In the study, the researchers designed a unique antigen targeting influenza virus that utilizes molecular mimicry by anti-idiotype antibodies, and showed that it can induce antibodies in inoculated animals that react broadly to multiple types of the virus. Following the announcement, shares of Chiome Bioscience widened their gains in the afternoon session and are currently at 94 yen, up 6 yen from the previous day.

A federal appeals court ruled in favor of Gilead Sciences on August 13, upholding a preliminary injunction that bars the defendants from importing or facilitating the sale of foreign-market Gilead-branded medications in the United States. The US Court of Appeals for the Fourth Circuit found that the differences between Gilead's HIV medication for the US market and the foreign versions being imported were material, not theoretical. The dispute dates to December 2024, when Gilead sued third-party administrator Meritain Health, pharmacy benefit manager ProAct, and pharmacies Rx Valet and Advanced Pharmacy over illegal imports of its best-selling HIV drug Biktarvy, a case that arose after a patient in Maryland received the medicine by mail from Turkey with label instructions written in Turkish. A federal district court in Baltimore granted the preliminary injunction after finding Gilead likely to succeed on its Lanham Act trademark violation and unfair competition arguments, and the order was later expanded to include new sellers CanaRx, ElectRx, and ScriptSourcing. The Fourth Circuit rejected the defendants' central argument that the imported and domestic versions of Biktarvy are interchangeable, holding that the two differ materially not only in packaging and labeling but also in the quality-control protocols each version undergoes before reaching a patient. A Gilead representative called the decision a patient-safety victory, and patient advocacy groups that filed amicus briefs supporting the company praised the ruling in similar terms.

GSK's Specialty Medicines unit, which now accounts for more than 40% of the company's sales and is expected to exceed 50% of total revenues by 2031, posted 14% sales growth at CER in the first half of 2026 on double-digit gains across HIV, Respiratory, Immunology & Inflammation and Oncology. New long-acting HIV injectables Cabenuva and Apretude account for around 25-30% of total HIV sales, while newer oncology drugs Jemperli and Ojjaara and recent launches including Blenrep, Exdensur and Penmenvy broaden the growth base, and GSK expects low double-digit percentage sales growth in the segment for 2026 at CER. The company now expects more than 20 phase III starts in 2026, more than twice the 10 originally contemplated, and has 19 assets in late-stage development or under regulatory review, with FDA decisions on bepirovirsen for chronic hepatitis B and neladalkib for non-small cell lung cancer expected later this year. GSK faces the loss of exclusivity for dolutegravir, the backbone of HIV medicines including Tivicay, Triumeq and Dovato, with patents expected to begin expiring in major markets around 2028-2029; dolutegravir-based products generated £2.74 billion in sales in the first half of 2026. GSK expects to launch twice-yearly long-acting injectables for treatment and PrEP between 2028 and 2030, and competes in Specialty Medicines with AstraZeneca, Merck, Sanofi, Gilead, Pfizer, J&J and Novartis, among others.

Assembly Biosciences has exercised its option to share 40% of U.S. development costs and profits for its herpes simplex virus helicase-primase inhibitor program under its collaboration with Gilead Sciences. The decision follows review of Gilead's complete development plan and budget for the program, which includes candidates GS-1179 and GS-5366. Gilead retains sole responsibility for further clinical development and commercialization, while Assembly Bio is eligible for up to $280 million in milestones and tiered royalties outside the U.S., with potential conversion to up to $330 million if certain opt-out rights are exercised. GS-1179 is expected to enter a Phase 2 trial in recurrent genital herpes by the end of 2026, with possible evaluation in combination with HIV pre-exposure prophylaxis. Assembly Bio's cash runway remains projected into 2029, including a $75 million collaboration extension fee from Gilead due in the fourth quarter of 2026.

AirNexis Therapeutics announced that AN01, a dual PDE3/4 inhibitor dry powder inhaler, met its primary endpoint in a Phase 2b COPD study conducted in China by its partner Haisco Pharmaceutical Group. The study, HSK39004-T1-202, randomized 195 patients on background single or dual bronchodilator therapy to receive AN01 0.75 mg, 1.5 mg, or placebo for four weeks. Both doses significantly improved lung function versus placebo, with treatment differences of 116 mL and 127 mL in FEV₁ AUC₀₋₁₂h at Week 4. AN01 was well tolerated, with no treatment-related adverse events in the 0.75 mg dose group, which is the dose being investigated in the Phase 3 program. AirNexis has completed its Phase 1 multiple ascending dose study in Australia and is preparing to initiate its Phase 2 program in 2027.

GSK plc has reached two regulatory milestones: its hepatitis B treatment Hibsago, also known as bepirovirsen, received its first global approval in Japan, and the FDA granted priority review to its cancer therapy Jemperli for locally advanced rectal cancer. Hibsago is the first and only treatment approved in Japan to deliver a functional cure for chronic hepatitis B, with late-stage studies showing nearly one in five patients achieved that outcome. GSK forecasts peak annual sales of more than £2 billion, approximately $2.73 billion, for Hibsago, contributing to its goal of over £40 billion in annual revenue by 2031. The FDA has set an action date for Jemperli in February 2027, though GSK notes the program's structure may allow an earlier decision. Jemperli already holds Breakthrough Therapy and Fast Track designations for this use, and an approval would expand its indications beyond endometrial cancer subtypes.

Gilead Sciences has received FDA approval for Bixlenvo, the smallest once-daily single-tablet regimen for HIV in virologically suppressed adults, making it the first and only option for patients unable to take existing single-tablet regimens. The drug combines bictegravir and lenacapavir, offering a high barrier to resistance and no cross-resistance to current antiretrovirals. This approval strengthens Gilead's HIV portfolio, which already includes Biktarvy, Descovy, and the rapidly growing Yeztugo, and the company has raised its 2026 HIV sales growth outlook to 9-10%, supported by a roughly $4 billion annualized PrEP business. Gilead expects Yeztugo sales to approach $1 billion in 2026, and its pipeline, including a once-weekly oral combination with Merck, offers additional upside. Shares of Gilead have gained 20.3% year to date, and the company currently holds a Zacks Rank #1 (Strong Buy).

Pfizer and BioNTech received U.S. FDA approval for their updated COMIRNATY COVID-19 vaccine targeting the XFG variant for high-risk individuals, while Pfizer and Valneva's Lyme disease vaccine candidate PF-07307405 had its Marketing Authorization Application validated by the European Medicines Agency based on Phase 3 trial data. These milestones highlight Pfizer's role in infectious disease prevention, with the Lyme vaccine potentially becoming a key proof point for its pipeline. However, unresolved legal and pricing pressures, including the Depo Provera settlement program, remain overhangs. Pfizer's narrative projects $54.9 billion in revenue and $9.2 billion in earnings by 2029, implying a 4.6% yearly revenue decline and a $1.7 billion earnings increase from $7.5 billion today, yielding a $29.19 fair value, a 4% upside to its current price. Some analysts assume revenue could fall to about US$50.6 billion by 2029, reinforcing concerns that pipeline wins may not fully offset pricing pressure and patent losses.

Gilead Sciences has snapped out of its slump, with shares surging from around $130 to $146 following its Q2 2026 earnings release on Aug. 4. The biotech reported $7.8 billion in sales, up 10% year over year and ahead of forecasts, but recorded a net loss of $8.45 per share due to in-process R&D charges from acquisitions including Arcellx. Investors focused on the HIV drug portfolio, where PrEP medicines hit over $1 billion in quarterly sales for the first time, with Descovy sales rising 48% and Yeztugo jumping from $15 million to $232 million. Management expects continued growth, with Yeztugo potentially reaching blockbuster status, and forecasts call for 2027 earnings between $9.19 and $11.10 per share, putting Gilead at 13 to 16 times forward earnings versus Amgen's nearly 20 times.

Sinocelltech's controlling subsidiary has received clinical trial approval from the National Medical Products Administration for its independently developed SCTA02A injection, which will be used in a clinical trial for chronic hepatitis B. This product is the first approved clinical candidate in the company's portfolio designed with the goal of achieving a functional cure for chronic hepatitis B. In the first quarter of 2026, Sinocelltech reported revenue of 323 million yuan and a net loss attributable to the parent company of 176 million yuan.

Zhixiang Jintai announced that it has received a drug clinical trial approval notice issued by the National Medical Products Administration. The clinical trial application for its investigational product GR2302 injection for subcutaneous use has been approved, with the indication being chronic hepatitis B. GR2302 injection is a bispecific antibody independently developed by the company, based on a TCR-mimic antibody and an anti-CD3 antibody. Currently, no drug targeting the same target has been approved for clinical trials in China. The company cautioned that after completing clinical trials, the drug still needs to submit a new drug application for marketing, and there are risks of uncertainty.

Merck and Gilead Sciences reported first-quarter 2026 earnings and announced two joint clinical milestones. Merck posted $16.3 billion in total sales, up 5% year-over-year, while Gilead reported $7.0 billion in total revenue, up 5% year-over-year. The European Medicines Agency's CHMP recommended Gilead's Trodelvy in combination with Merck's Keytruda for first-line PD-L1-positive triple-negative breast cancer. Phase 3 results from the ISLEND-1 and ISLEND-2 trials showed a once-weekly oral combination of Gilead's lenacapavir and Merck's islatravir achieved noninferior virologic suppression compared to daily regimens. Both companies raised full-year guidance, with Merck targeting $65.8 billion to $67.0 billion in sales and Gilead targeting $30.0 billion to $30.4 billion in product sales.

Omeros Corporation reported a second-quarter 2026 net income of $13.23 million, or $0.18 per share, swinging from a net loss of $25.42 million, or $0.43 per share, a year earlier. Net revenue reached $28.55 million, driven entirely by YARTEMLEA sales of $32.2 million, which grew 190% from the first quarter of 2026. The company plans to begin enrollment by the end of 2026 in two YARTEMLEA studies, one for hyperinflammatory acute respiratory distress syndrome and another for prophylactic use in pediatric patients with predictably severe transplant-associated thrombotic microangiopathy. Omeros is also initiating a nonclinical study for OMS527 in response to an FDA request, with an inpatient clinical trial targeted to start by year-end 2026, while IND-enabling studies for OMS805 are underway ahead of a planned Phase 1b trial in late 2027. As of June 30, 2026, the company held $132.0 million in cash and short-term investments, and shares surged 15.85% to $15.61 in overnight trading.

Atea Pharmaceuticals outlined peak annual U.S. net revenue potential in excess of $700 million for its hepatitis C program, with a focus on a mid-2028 launch. The company reported positive top-line results from its Phase III C-BEYOND trial, where bemnifosbuvir met both primary and secondary endpoints and demonstrated statistical non-inferiority to Epclusa, achieving a 93.9% SVR rate in the mITT population compared with 94.8% for SOF/VEL. Atea's second Phase III trial, C-FORWARD, is fully enrolled with more than 880 patients, and top-line results are expected in early Q1 2027, with an NDA submission anticipated in the second quarter of 2027. The company also initiated a first-in-human Phase I trial of AT-587 for chronic hepatitis E and reported cash and investments of $219.5 million as of June 30, 2026, with runway anticipated through 2027.

Fosun Pharma Industrial, a controlled subsidiary of Fosun Pharma, announced on August 13, 2026, the initiation of a Phase II clinical trial in China for FXS7553 in the treatment of chronic obstructive pulmonary disease. FXS7553 is a small-molecule oral DPP-1 inhibitor independently developed by the group, intended for the treatment of non-cystic fibrosis bronchiectasis, chronic obstructive pulmonary disease, and other conditions. Another indication, non-cystic fibrosis bronchiectasis, is also in Phase II clinical development in China. As of July 2026, cumulative R&D investment in this drug amounted to approximately 151 million yuan.

Merck has secured acceptance from both the FDA and the European Medicines Agency for supplemental applications to expand the use of its antibody ENFLONSIA for preventing RSV in young children at elevated risk. The filings seek to broaden the indication into vulnerable pediatric groups where preventative options remain limited. The dual regulatory milestones underscore Merck's efforts to diversify its portfolio beyond oncology as attention on the future of Keytruda intensifies. A key signpost will be the FDA's March 22, 2027 PDUFA decision on the supplemental Biologics License Application, alongside the EMA outcome, which will determine whether this potential second-season use can become a meaningful pediatric RSV franchise.

Gyre Therapeutics reported second quarter 2026 revenue of $29.1 million and a GAAP basic loss per share of $0.12, while affirming its full-year 2026 revenue guidance of $100.5 to $111.0 million. The company's lead product ETUARY generated $28.0 million in sales, up from $23.5 million a year earlier, though total revenue dipped 2% due to the end of a collaboration agreement with Astellas Pharma. In May, China's Center for Drug Evaluation accepted the New Drug Application for F351 as a treatment for chronic hepatitis B-induced liver fibrosis, and Gyre closed its all-stock acquisition of Cullgen valued at approximately $300 million. Research and development expenses surged to $19.1 million from $8.4 million, driven by clinical trial costs and a milestone payment tied to the F351 application, contributing to a net loss of $14.3 million compared to a $2.2 million loss in the prior-year period.

Zhejiang Wolwo Bio-technology announced that the clinical trial application for its chemical Class 1 new drug S01D tablets has been formally accepted by the National Medical Products Administration. The drug is indicated for adult patients with drug-resistant pulmonary tuberculosis and is a Class 1 chemical drug with a new molecular entity and novel mechanism. Non-clinical studies suggest superior activity against Mycobacterium tuberculosis. As of the disclosure date, no identical chemical drug has been approved for marketing domestically or internationally. According to regulations, the Center for Drug Evaluation will decide within 60 days of acceptance whether to approve the clinical trial. Subsequent steps, including Phase I, II, and III clinical trials and the marketing authorization application, must still be completed, and outcomes are subject to significant uncertainty. The company stated that this acceptance marks an important R&D milestone in the field of drug-resistant pulmonary tuberculosis.

Vir Biotechnology announced that top-line data from its ECLIPSE 1 study in hepatitis delta will be reported in the fourth quarter of 2026, with readouts from ECLIPSE 2 and ECLIPSE 3 following in the first quarter of 2027. The company completed enrollment in ECLIPSE 2 during the second quarter and has now finished enrollment across all three registrational ECLIPSE studies. Vir ended the quarter with approximately $1.01 billion in cash, cash equivalents and investments, an increase of $198.5 million, and projects its cash runway into the second half of 2028. License and collaboration revenue was $238.9 million, largely tied to an upfront payment from Astellas, and net income was $80.1 million. The company also highlighted progress in its oncology program, with VIR-5500 advancing through multiple expansion cohorts and a goal to initiate Phase III registrational trials next year.

Youcare Pharmaceutical announced that its YKYY017 inhalation aerosol has received clinical trial approval from the National Medical Products Administration for a new indication, intended for the treatment and prevention of human coronavirus OC43-related respiratory infections. The drug is a lipopeptide compound jointly developed by the company and the Institute of Pathogen Biology at the Chinese Academy of Medical Sciences. It belongs to the latest generation of coronavirus membrane fusion inhibitors, blocking virus-host cell fusion by competitively binding to the HR1 region of the S2 subunit of the coronavirus spike protein. It exhibits broad-spectrum inhibitory activity against multiple coronaviruses, including SARS-CoV-2 and HCoV-OC43.

Merck & Co., Inc., Rahway, N.J., USA announced second-quarter 2026 worldwide sales of $16.6 billion, a 5% increase from the prior year, and narrowed its full-year 2026 sales outlook to between $66.3 billion and $67.3 billion. KEYTRUDA and KEYTRUDA QLEX sales reached $8.4 billion, including $463 million from the newly launched KEYTRUDA QLEX, while WINREVAIR sales grew 75% to $588 million and Animal Health sales rose 8% to $1.8 billion. The company reported a GAAP loss per share of $0.54 and a non-GAAP loss per share of $0.13, both reflecting a $2.31 per share charge for the acquisition of Terns Pharmaceuticals. Key regulatory milestones included U.S. FDA approval of LIPFENDRA, the first once-daily oral PCSK9 inhibitor, and positive Phase 3 results for the investigational sacituzumab tirumotecan in endometrial cancer and for a once-weekly oral HIV regimen of islatravir and lenacapavir in collaboration with Gilead. Merck now expects full-year non-GAAP EPS between $2.66 and $2.76, which includes charges of $2.43 per share related to the Terns acquisition.

The positive rate for COVID-19 tests has recently climbed to 20.3%, driving up market demand for antiviral drugs. Yet physical pharmacies are widely out of stock, with some staff even recommending anti-flu medications such as oseltamivir and baloxavir marboxil. Six domestically developed oral COVID-19 treatments have now been approved in China, including Genuine Biotech’s Jiebeian, Simcere Pharmaceutical’s Xiannuoxin, Junshi Biosciences’ Mindewei, Zonsen Pharmaceutical’s Leruiling, Cosunter’s Taizhongding, and Aisen Pharmaceutical’s Aoweining. However, multiple pharmacies reported that none of these drugs appeared in their inventories. Online platforms, by contrast, all have them available. Data from JD Pharmacy shows that transaction volumes for COVID-19 medications in July rose nearly fourfold month on month. Faced with surging demand, Simcere Pharmaceutical said it has activated an emergency production mechanism. Cosunter noted that sales of Taizhongding have increased and it will broaden hospital coverage. Junshi Biosciences has also launched an emergency plan to ensure supply. Industry insiders point out that earlier regulatory restrictions confined COVID-19 drugs mainly to hospitals and online sales, and they are calling for a reassessment of retail channel controls.

Hotgen Biotech announced that its subsidiary Shun Jing Pharmaceutical has received a Drug Clinical Trial Approval Notice issued by the National Medical Products Administration. The clinical trial application for the innovative drug SGC001 injection for a new indication, anticipated severe acute pancreatitis, has been approved. The drug previously received clinical approvals from the U.S. FDA and China's CDE, and was granted Fast Track designation by the FDA. The Phase II clinical trial is currently progressing smoothly.

Basilea Pharmaceutica has received an additional $30 million from the U.S. Biomedical Advanced Research and Development Authority after meeting a key enrollment milestone in its Phase 3 program for the novel antifungal Fosmanogepix. The funding, awarded under an existing Other Transaction Agreement, will help advance late-stage studies targeting invasive fungal infections such as aspergillosis and candidiasis. This new tranche builds on $93 million already committed since 2024, with BARDA covering about 60% of total project costs, and if all contract options are exercised, Basilea could receive up to $268 million in non-dilutive funding over 12 years. Fosmanogepix is a first-in-class broad-spectrum antifungal that has shown activity against drug-resistant Candida strains, including Candida auris, and rare molds such as Fusarium and Scedosporium, with both intravenous and oral formulations under evaluation in the Phase 3 FAST study in candidemia and invasive candidiasis and the FORWARD study in invasive mold infections. The drug has received Fast Track and Orphan Drug designations as well as Qualified Infectious Disease Product status from the FDA.

RedHill Biopharma is finalizing development steps and partnership talks for its investigational drug opaganib as a potential treatment for Bundibugyo ebolavirus disease, with confirmed cases rising to 3,221 and deaths to 1,407. Discussions are ongoing with the African Medicines Agency's Emergency Task Force, Uganda's Ministry of Health, Mbarara University of Science and Technology, and the Democratic Republic of Congo's Scientific Advisory Committee. Professor Pauline Byakika-Kibwika, Vice Chancellor of Mbarara University, stressed the urgent need for new therapeutic options, noting opaganib's oral formulation, human safety data, and supportive evidence warrant immediate evaluation. RedHill's Chief Operating Officer Gilead Raday highlighted Phase 3 COVID-19 data showing a 70.2% mortality reduction when opaganib was added to remdesivir, along with preclinical Ebola studies funded by the U.S. Army Medical Research Institute of Infectious Diseases that demonstrated increased survival and a synergistic effect with remdesivir.

The University of Oxford has launched the world's first human trial of a vaccine against the Bundibugyo strain of Ebola, with the first volunteer receiving the prototype ChAdOx1 BDBV vaccine. The phase one study will enroll around 50 healthy volunteers to assess safety and immune response. The vaccine was developed by the Oxford Vaccine Group and the Pandemic Sciences Institute, both part of the University of Oxford. The Serum Institute of India manufactured and stockpiled approximately 620,000 doses, including 4,000 trial doses used in this study. Meanwhile, the Democratic Republic of the Congo has reported a cumulative total of 2,905 Ebola cases and 1,269 deaths, with the rising numbers partly due to the integration of databases from Ituri and North Kivu provinces into the national system. The Congolese government has allocated 50 million US dollars to tackle the outbreak, focusing on laboratories, medical equipment, community surveillance, and patient care.

Medical experts warn that hepatitis A and B viruses are silent threats that can lead to cirrhosis and liver cancer. Hepatitis A is transmitted through food and water, typically causing acute infection and does not become chronic. Hepatitis B is transmitted through blood, bodily fluids, or from mother to child, and can develop into chronic infection, increasing the risk of cirrhosis and liver cancer. Blood tests and appropriate vaccination play a crucial role in prevention and long-term risk reduction. Dr. Sukprasert Jutakorkiat, a gastroenterologist at Vechthani International Hospital, explains that hepatitis B can be transmitted through blood and bodily fluids, including mother-to-child transmission during childbirth, which is a major cause of infection from childhood. Those infected at birth have a higher chance of developing chronic infection than at other ages. Diagnosis is made through blood tests to assess the type of infection, immunity, and disease severity. Treatment for hepatitis A is mostly symptomatic, while chronic hepatitis B may be treated with long-term antiviral medication to control viral load and reduce the risk of complications. The hepatitis A vaccine is generally given in two doses, about six to twelve months apart. The hepatitis B vaccine is given in three doses at months zero, one, and six, and after completing the series, an Anti-HBs test should be done to assess immunity.

Gilead Sciences and Merck announced that the investigational once-weekly oral single-tablet HIV treatment regimen of islatravir 2 mg and lenacapavir 300 mg maintained virological suppression in adults with HIV who switched from daily antiretroviral therapy, according to Week 48 results from the Phase 3 ISLEND-1 and ISLEND-2 trials. In ISLEND-1, no participants who switched to the once-weekly regimen had HIV-1 RNA of 50 copies per milliliter or more at Week 48, compared to 0.3 percent of those who remained on BIKTARVY, while in ISLEND-2 the rates were 0.3 percent for the once-weekly regimen versus 1.3 percent for standard-of-care daily treatments. The safety profile of the once-weekly combination was generally similar to the comparator regimens, with no new safety concerns identified, and participants who switched reported higher treatment satisfaction and lower treatment burden. The data will be presented at the 26th International AIDS Conference and will form the basis of regulatory submissions, with the potential to make this the first once-weekly oral HIV treatment option.

A relevant official from the Ministry of Industry and Information Technology stated that 38 innovative drugs were approved for market in the first half of this year, of which 31 were domestic innovative drugs, accounting for over 80%. A batch of world-first innovative achievements, including the world's first antibody drug against hepatitis D and the world's first CAR-T therapy for solid tumors, received concentrated approval. The total value of out-licensing deals for innovative drugs exceeded 100 billion US dollars. Affected by this news, the Shanghai STAR Board Biomedical Index rose strongly by 3.12%, and the STAR Board Medical ETF from China Asset Management rose by over 2.68%. This ETF has seen net capital inflows for 16 consecutive days, attracting a total of 284 million yuan. Shenwan Hongyuan Research pointed out that policies are giving key support to cutting-edge fields such as cell and gene therapy, and the formal review pass rate for the commercial insurance innovative drug catalog is as high as 94%, which will accelerate the clinical application of innovative drugs.

ACTG has announced the opening of A5432, a qualitative study designed to understand factors affecting the use of long-acting antiretroviral therapy among people living with HIV who previously could not maintain viral suppression on daily oral regimens. The study will conduct in-depth interviews with approximately 30 participants from the landmark LATITUDE trial and focus groups with up to 48 LATITUDE staff members, exploring experiences with long-acting injectable cabotegravir and rilpivirine, barriers to use, and the impact of conditional economic incentives. LATITUDE had shown that long-acting ART was superior to daily oral therapy in this population, leading an independent monitoring board to recommend halting randomization in February 2024. A5432 aims to inform future trial design and real-world implementation by examining the transition from study-based care to standard medical channels. The protocol was developed by ACTG’s Behavioral Science Subcommittee with input from its Implementation Science Subcommittee and representatives from the National Institute of Mental Health and the National Institute of Allergy and Infectious Diseases.