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✦ Once a Week: Islatravir, Lenacapavir and Oral PrEPNarrow moat

Gilead Sciences (GILD) — the future bets

Gilead's weekly pills, for treatment with Merck and for prevention on its own, carry lenacapavir patents to 2037 and are the bridge past Biktarvy.

The next step in Gilead's switching strategy is a weekly pill. In the second quarter of 2026 it reported positive Phase 3 results from ISLEND-1 and ISLEND-2, run with Merck, testing a once-weekly oral combination of islatravir 2 mg and lenacapavir 300 mg in patients whose virus was suppressed and who switched from Biktarvy or other regimens1. In prevention, the FDA accepted an application for lenacapavir 300-mg tablets as a potential once-weekly oral PrEP, with a decision date of 2 February 20272.

Gilead weekly HIV productsISLEND-1 and -2positive Phase 3,with Merck, switchfrom BiktarvyOral lenacapavirPrEPFDA decision 2February 2027Patentlenacapavir to 2037Biktarvy genericsnot before 1 April 2036Gilead Q2 2026 results release; Form 10-K FY2025; Form 8-K of 6 October 2025
The next backbone arrives with a year to spare.

Both products carry lenacapavir, whose patents run to 20373, a year beyond Biktarvy's earliest US generic date of April 20364. That is the point: Gilead is building the products it will move patients to before Biktarvy faces generics.

The treatment combination is shared with Merck, which contributes islatravir5. That makes it a different proposition from Biktarvy, which Gilead owns outright: moving a patient to a partnered product keeps the patient but is likely to share the economics, on terms the filings cited here do not set out.

The prevention tablet sits beside Yeztugo, the twice-yearly injection that sold $232 million in the second quarter6, giving Gilead daily, weekly and twice-yearly options in PrEP. That breadth is an advantage against ViiV, whose prevention product is an injection.

The chief executive called the quarter one of "significant clinical progress"7, and the HIV results were the core of it. The ISLEND trials tested patients who switched from Biktarvy (ISLEND-1) or from other standard regimens (ISLEND-2)8, which is exactly the population Gilead needs to move before 2036.

The weekly pill succeeds if doctors move stable patients to it. If, two years after approval, its sales are below 10% of Biktarvy's, Gilead will reach 2036 without its next backbone in place.

Moat trajectory: Widening

Positive Phase 3 ISLEND results; oral PrEP decision 2 February 2027.

The number that tests this moat
Moat Explorer calc
Biktarvy share of HIV sales, full year
69.1% ($14,334M of $20,752M in 2025)

How much of HIV the weekly pill must eventually replace; still above 65% in 2030 would mean the switch is late.

How it's calculated: Biktarvy product sales divided by total HIV product sales, Gilead Form 10-K FY2025.
Source: Moat Explorer calculation from Gilead Sciences filings ↗
References
  1. ReportedIn the second quarter of 2026 it reported positive Phase 3 results from ISLEND-1 and ISLEND-2, run with Merck, testing a once-weekly oral combination of islatravir 2 mg and lenacapavir 300 mg in patients whose virus was suppressed and who switched from Biktarvy or other regimens.
    Gilead Sciences second-quarter 2026 results release, Form 8-K exhibit 99.1 - revenue by product, income statement, cash flow, balance sheet, pipeline updates and 2026 guidance - pipeline, regulatory and business development updates. — Q2 2026 · publ. 4 August 2026 · source ↗
  2. ReportedIn prevention, the FDA accepted an application for lenacapavir 300-mg tablets as a potential once-weekly oral PrEP, with a decision date of 2 February 2027.
    Gilead Sciences second-quarter 2026 results release, Form 8-K exhibit 99.1 - revenue by product, income statement, cash flow, balance sheet, pipeline updates and 2026 guidance - pipeline, regulatory and business development updates. — Q2 2026 · publ. 4 August 2026 · source ↗
  3. ReportedBoth products carry lenacapavir, whose patents run to 2037, a year beyond Biktarvy's earliest US generic date of April 2036.
    Gilead Sciences Form 10-K for 2025 - Item 1A risk factors and pricing regulation: the IRA, Medicare negotiation, Medicaid, the ACA and tariffs. — FY2025 · publ. 24 February 2026 · source ↗
  4. ReportedBoth products carry lenacapavir, whose patents run to 2037, a year beyond Biktarvy's earliest US generic date of April 2036.
    Gilead Sciences Form 8-K of 6 October 2025 - settlement agreements with Lupin, Cipla and Laurus Labs; no generic entry of Biktarvy expected in the United States before 1 April 2036. — October 2025 · publ. 6 October 2025 · source ↗
  5. ReportedThe treatment combination is shared with Merck, which contributes islatravir.
    Gilead Sciences Form 10-K for 2025 - Item 1 business and the revenue-by-product table: products, programs, employees and manufacturing. — FY2025 · publ. 24 February 2026 · source ↗
  6. ReportedThe prevention tablet sits beside Yeztugo, the twice-yearly injection that sold $232 million in the second quarter, giving Gilead daily, weekly and twice-yearly options in PrEP.
    Gilead Sciences second-quarter 2026 results release, Form 8-K exhibit 99.1 - revenue by product, income statement, cash flow, balance sheet, pipeline updates and 2026 guidance - pipeline, regulatory and business development updates. — Q2 2026 · publ. 4 August 2026 · source ↗
  7. ReportedThe chief executive called the quarter one of "significant clinical progress", and the HIV results were the core of it.
    Gilead Sciences second-quarter 2026 results release, Form 8-K exhibit 99.1 - revenue by product, income statement, cash flow, balance sheet, pipeline updates and 2026 guidance - revenue by product and product group and the drivers of each. — Q2 2026 · publ. 4 August 2026 · source ↗
  8. ReportedThe ISLEND trials tested patients who switched from Biktarvy (ISLEND-1) or from other standard regimens (ISLEND-2), which is exactly the population Gilead needs to move before 2036.
    Gilead Sciences second-quarter 2026 results release, Form 8-K exhibit 99.1 - revenue by product, income statement, cash flow, balance sheet, pipeline updates and 2026 guidance - pipeline, regulatory and business development updates. — Q2 2026 · publ. 4 August 2026 · source ↗
Sources
Generated October 4, 2026