Hepatitis B Drug Developments and Lilly's Obesity Drug Returns

Key Takeaways

• FDA accepted bepirovirsen for priority review with a PDUFA goal date of October 26, 2026, and granted Breakthrough Therapy designation.
• B-Well 1 (NCT05630807) and B-Well 2 (NCT05630820) support the hepatitis B filing; bepirovirsen is not yet approved anywhere.
• CVS Caremark will add Zepbound back as a preferred commercial option October 1, 2026, and unblock Foundayo June 1, 2026.
• Plan sponsors still decide whether to adopt template coverage; access is not automatic for every member.

What changed for the hepatitis B drug bepirovirsen?

GSK announced that FDA accepted a New Drug Application for bepirovirsen, an investigational antisense oligonucleotide for adults with chronic hepatitis B, under priority review. The agency also granted Breakthrough Therapy designation, building on a prior Fast Track designation. The PDUFA goal date is October 26, 2026, according to GSK’s April 28, 2026 release.

GSK licensed bepirovirsen from Ionis Pharmaceuticals. The company states the product is not approved anywhere yet. That single fact should gate every commercial model: model scenarios around Q4 2026 U.S. action, not current revenue.

Which trials underpin the hepatitis B filing?

The filing rests on Phase 3 B-Well 1 and B-Well 2. Public registry records identify the studies as NCT05630807 and NCT05630820. GSK describes both as global, randomized, double-blind, placebo-controlled trials in nucleos(t)ide analogue–treated adults with baseline HBsAg at or below 3,000 IU/mL.

• Primary focus: functional cure rates versus standard of care alone
• Functional cure definition used by GSK: HBsAg undetectable for at least 24 weeks after stopping all treatment
• Geography: multi-country programs spanning 29 countries in company descriptions

Until peer-reviewed numbers are locked into labeling, teams should treat headline functional-cure percentages in secondary coverage as provisional and verify against primary publications or the eventual FDA label.

How did CVS Caremark change Lilly obesity drug access?

On May 28, 2026, CVS Health said Caremark will add Zepbound (tirzepatide) back to common commercial formularies as an additional preferred option effective October 1, 2026. The same announcement said Caremark will remove the new-to-market block on Foundayo (orforglipron) effective June 1, 2026, where plans approve coverage. See the CVS Caremark PR Newswire release.

Lilly separately said all three large U.S. pharmacy benefit managers will cover its obesity portfolio, with Foundayo template coverage beginning June 1 and broader Zepbound template access by October 1. Eligible commercially insured patients may pay as little as $25 per month under manufacturer savings programs, per Lilly’s May 28, 2026 PR Newswire statement.

What does the Zepbound label already establish?

Zepbound is FDA-approved tirzepatide for chronic weight management with diet and activity, and for moderate to severe obstructive sleep apnea in adults with obesity, per the FDA prescribing information. The label carries a boxed warning about thyroid C-cell tumors observed in rats and contraindicates use in patients with medullary thyroid carcinoma history or MEN2.

Formulary restoration does not rewrite those safety constraints. Medical affairs and payer teams still need prior-authorization alignment to labeled indications and risk counseling.

How should portfolio teams connect hep B and obesity news?

These are different therapeutic areas, but they collide in capital allocation and U.S. access operations. Hepatitis B assets now have a dated FDA clock into late October 2026. Obesity franchises are renegotiating PBM preference after a year of exclusive Wegovy positioning on some Caremark templates. BD teams should update rNPV models for bepirovirsen with priority-review timing and separately re-forecast tirzepatide and orforglipron volumes under co-preferred GLP-1 templates.

Do not assume every employer adopts Caremark’s template. CVS explicitly said plan sponsors retain discretion to customize coverage.

What remains unproven?

Bepirovirsen’s U.S. benefit–risk and labeled population are not final until FDA acts. Functional-cure durability beyond trial definitions, real-world adherence to weekly injections, and pricing versus lifelong nucleoside analogues remain open. On obesity, net prices after rebates, step edits, and Medicare Bridge eligibility details will determine realized access more than headline formulary wins.

Related NovaPharma coverage

• Gilead Hepcludex FDA approval for hepatitis D
• Lilly Foundayo orforglipron FDA approval
• FDA Zepbound obstructive sleep apnea approval

Frequently Asked Questions

Primary Sources

1. GSK: bepirovirsen FDA priority review
2. ClinicalTrials.gov: B-Well 1 NCT05630807
3. PR Newswire: CVS Caremark GLP-1 formulary update
4. FDA label: Zepbound (tirzepatide)