GSK/Ionis Bepirovirsen Achieves 19% Functional Cure in Hepatitis B

GSK and Ionis just dropped Phase 3 data showing bepirovirsen achieved a nineteen percent functional cure rate in chronic hepatitis B — a disease that has never had a functional cure.

Add a two-hundred-forty-five percent stock surge for Spero on an oral antibiotic breakthrough, a new Imfinzi bladder cancer approval, and CVS unlocking Lilly's full obesity franchise. Let's go.

Welcome to The Pharma Closeout for Thursday, May twenty-eighth, twenty twenty-six. I'm Alex Mercer.

And I'm Maya Patel. Let's get into it.

Top story. GSK and Ionis presented detailed Phase 3 results today from the B-Well 1 and B-Well 2 trials for bepirovirsen in chronic hepatitis B. Topline numbers were first announced back in January — today's presentation delivered the full dataset. Pooled results: a nineteen percent functional cure response rate. Two hundred thirty-three of one thousand two hundred twenty patients achieved functional cure after six months of treatment. Bepirovirsen already carries Breakthrough Therapy Designation and Priority Review from the FDA. Physicians at the presentation called it a historic moment. Analysts are using the words clear blockbuster potential.

Functional cure in hep B means sustained HBsAg loss off treatment — not viral suppression under indefinite nucleoside analog therapy. That distinction matters enormously. Nineteen percent gets the headline, but the real benchmark is what exists today: functionally zero with standard of care.

Three hundred million people globally live with chronic hep B, and essentially none of them have had a curative option. Even conservative penetration modeling puts this well into blockbuster revenue territory — the unmet need is simply that enormous.

The eighty-one percent non-response is the obvious counterpoint, and it will be the first question on every analyst call. Durability beyond the six-month treatment window is the next data point the market demands — how many of those functional cures hold at twelve months, at twenty-four? Combination strategies to boost that rate are the logical development path. But as proof-of-concept that antisense-mediated HBsAg knockdown can achieve functional cure, this is the strongest infectious disease clinical readout GSK has delivered in years.

There's a platform story here too. Ionis has been valued primarily for its neurological and cardiometabolic franchises. Bepirovirsen succeeding in infectious disease materially expands how the market should think about where antisense technology can reach.

Priority Review could put an approval decision in front of us before year-end. If that lands, GSK delivers the first curative option for a disease that has been suppression-only for decades. That is not an incremental advance — it is a categorical shift in how chronic hep B gets treated.

GSK keeps showing up today, and we'll circle back to why in a moment. But shifting to the deal side — the commercial catalyst with the most immediate revenue implications is in obesity. CVS Caremark is restoring coverage for Lilly's Zepbound and adding the recently approved oral Foundayo to its formulary, extending access to millions of Americans on private insurance plans. According to Lilly, all three of the nation's largest PBMs now cover both products — putting Lilly on equal competitive footing with Novo Nordisk in obesity at the formulary level for the first time.

Here's the budget version. PBM formulary access is the single largest commercial bottleneck for obesity drugs right now — bigger than pricing, bigger than prior authorization hurdles. Unlocking all three major PBMs doesn't just lift Lilly's sales outlook. It forces Novo into a pricing and access response on Wegovy. Prescribers can now choose between platforms based on clinical profile rather than formulary restrictions. The competitive dynamic just moved from clinical differentiation to pure commercial execution.

Now, why GSK keeps coming up. Spero Therapeutics surged two hundred forty-five percent — from roughly sixty-eight cents to two thirty-five — after its Phase 3 PIVOT-PO trial of tebipenem HBr in complicated UTIs was stopped early for efficacy. Non-inferiority to IV imipenem-cilastatin at the ten percent margin consistent with FDA guidance. GSK is the development partner. If approved, tebipenem would be the first oral carbapenem for hospitalized cUTI patients, according to the company.

An early efficacy stop in a non-inferiority design carries particular weight — the statistical threshold in an NI framework is already conservative, and crossing it early enough to halt enrollment means the effect size was unambiguous. Clinically, this is an oral option in a setting that currently mandates IV access. For hospital pharmacy committees, that changes discharge planning and resource allocation conversations.

Rapid fire on the rest. BridgeBio reported positive Phase 3 interim FORTIFY results for oral BBP-418 in limb-girdle muscular dystrophy type 2I/R9 at the MDA Conference. Improved mobility, reduced muscle damage biomarkers, filing planned this year, zero approved treatments for this disease, stock up roughly fifteen percent. Also in rare disease, RA Capital is investing thirty million dollars in Secretome Therapeutics for a cell therapy targeting the heart muscle weakness tied to Duchenne muscular dystrophy — a novel angle in that space.

BridgeBio building a second rare disease pillar beyond acoramidis, in a space with zero competition — if BBP-418 reaches approval, the pipeline diversification discount the market applies to this company has to narrow.

And Kardigan Therapeutics, founded by former MyoKardia executives, is planning an IPO with three mid- to late-stage cardiovascular medicines licensed from Sanofi, Ionis, and BMS. When the team that built mavacamten from scratch launches a new cardiovascular platform, institutional capital pays attention.

Also worth noting on the regulatory front — the FDA today approved AstraZeneca's Imfinzi in combination with BCG for adult patients with BCG-naïve, high-risk non-muscle-invasive bladder cancer. According to AstraZeneca, this is the first and only immunotherapy combination approved for this population. It marks Imfinzi's second bladder cancer indication.

AZ is methodically building Imfinzi's franchise across the entire bladder cancer continuum — muscle-invasive last year, BCG-naïve NMIBC today. Securing the first immunotherapy combo label in this setting gives AstraZeneca genuine positioning advantage as the GU oncology competition with Merck's Keytruda intensifies.

On the pricing front, STAT News reports the secrecy around Trump's most-favored-nation drug pricing order is lifting. Specific drugs are now being named — AstraZeneca's Baxfendy for hypertension and Novo Nordisk's insulin Awiqli among the targets. Earlier Benzinga coverage cited potential price cuts of up to eighty percent.

Named-drug targeting is a meaningful escalation. When specific products carry specific price cut expectations, this stops being a policy debate and becomes a balance sheet question for every company on that list.

And the exposure extends well beyond two drugs. Every company without a voluntary pricing deal is recalculating its MFN risk product by product right now. Novo and AstraZeneca are the first names, but the industry is watching how fast that list grows — because the longer it gets, the harder it becomes for any single manufacturer to hold the line.

What to watch from here. ASCO twenty twenty-six abstracts dropped today — early data snapshots from Merck, BioNTech, Eli Lilly, and Moderna spanning multiple tumor types and treatment modalities. Full plenary and oral presentations begin over the coming days, and the datasets that land first tend to set the competitive narrative for the rest of the year. The one to circle: Akeso's PD-1/VEGF bispecific heads to a plenary session, one of the highest-profile oncology data slots there is.

ASCO weeks reshape competitive narratives across tumor types simultaneously. Akeso's bispecific data could recalibrate how the market prices the entire PD-1/VEGF wave originating from China — and with Merck, Lilly, BioNTech, and Moderna all presenting, the checkpoint landscape could shift materially in a single week. Anyone tracking oncology strategy should clear their calendar.

And circling back to today's leads — bepirovirsen's Priority Review clock is ticking toward a PDUFA date, Spero needs to formalize its tebipenem NDA after that early stop, and BridgeBio is targeting a BBP-418 filing before year-end. Infectious disease and rare disease — two historically quiet pipeline areas — suddenly have multiple high-impact regulatory catalysts stacking up in the second half of twenty twenty-six.

When a therapeutic area wakes up like this, capital and talent follow fast. The companies positioned in these spaces today could look very different by December — and the smart positioning happens now, not after the approvals land.

That is your Pharma Closeout for Thursday, May twenty-eighth. Bepirovirsen delivering a nineteen percent functional cure in chronic hep B — a first for a disease affecting hundreds of millions. Spero surging two hundred forty-five percent on an oral carbapenem breakthrough. Imfinzi expanding AstraZeneca's bladder cancer franchise. And Lilly locking down full PBM coverage for its obesity products — the commercial race with Novo just entered a new phase. ASCO data starts flowing this week, so follow us on Spotify and drop a rating — you do not want to miss what is coming. We're back tomorrow.

Enjoy your evening. See you tomorrow. ## EPISODE METADATA **Title:** GSK/Ionis Bepirovirsen Achieves 19% Functional Cure in Hepatitis B; Spero Surges 245% on Oral Carbapenem Data; CVS Covers Lilly Obesity Drugs | May 28, 2026 **Description:** Bepirovirsen hits 19% functional cure rate in Phase 3 chronic HBV trials — a first for a disease affecting 300 million. Plus Spero's 245% surge on tebipenem, AstraZeneca's Imfinzi NMIBC approval, CVS restoring Lilly obesity drug coverage, BridgeBio LGMD data, Kardigan IPO plans, and ASCO 2026 abstracts drop. **Tags:** bepirovirsen, GSK, Ionis, hepatitis B, functional cure, Spero Therapeutics, tebipenem, oral carbapenem, cUTI, CVS, Eli Lilly, Zepbound, Foundayo, obesity drugs, AstraZeneca, Imfinzi, durvalumab, bladder cancer, NMIBC, BridgeBio, BBP-418, LGMD, muscular dystrophy, Kardigan Therapeutics, MyoKardia, Secretome Therapeutics, Duchenne, ASCO 2026, Trump drug pricing, MFN, Akeso, Novo Nordisk, Merck, BioNTech, Moderna, pharma, pharmaceutical, FDA, clinical trials, biotech, drug approvals #