Kodiak’s Zenkuda Met Both DAYBREAK Endpoints With 54% of Patients on Six Month Dosing as Mirum’s Brelovitug Hit in Hepatitis Delta and AstraZeneca Bought a $2B Summit Stake (September 29, 2026)

Last updated: September 29, 2026

Kodiak Sciences’ Zenkuda and KSI-501 both met their DAYBREAK Phase 3 primary endpoints in wet AMD, with 54% of Zenkuda patients reaching a six month dosing interval. Mirum’s brelovitug hit in hepatitis delta, and AstraZeneca bought a $2 billion Summit stake after the close.

This briefing covers the news of Monday, September 28, 2026, across biotech, pharma, medtech, and policy, with primary sourced data tables and the catalysts now in play.

What did Kodiak’s DAYBREAK Phase 3 show for Zenkuda and KSI-501 in wet AMD?

Both drugs met their primary endpoints. Zenkuda (tarcocimab tedromer) and KSI-501 (tabirafusp alfa tedromer) each delivered vision gains non inferior to aflibercept at one year in treatment naive wet age related macular degeneration, and 54% of Zenkuda patients reached a six month dosing interval.

Kodiak Sciences reported topline results Monday morning from DAYBREAK, a Phase 3 study that randomized treatment naive wet AMD patients across three arms: Zenkuda dosed on an individualized treat to dryness schedule, KSI-501 on a fixed schedule, and aflibercept as the active comparator.

The safety line matters as much as the efficacy line. Intraocular inflammation is the failure mode that has dogged long interval retina programs, and Kodiak reported 0% for Zenkuda and 0.4% for KSI-501. KSI-501, a bispecific that adds IL-6 inhibition to VEGF blockade, also has a Phase 3 trial (ALTO) enrolling in diabetic macular edema, and the company plans post hoc work to identify wet AMD subgroups that benefit from the IL-6 arm.

Why did Kodiak stock close up 178% on September 28?

KOD closed at 89.92, up 178.0% from Friday’s 32.35 close (our arithmetic from exchange settled closes), in the first reaction session to DAYBREAK. The market repriced a company whose lead asset had been written off after earlier Phase 3 failures.

Kodiak’s chief medical officer put the arc plainly: “Four years and seven months after our first Phase 3 readout, Zenkuda’s profile has come fully into focus.” Tarcocimab failed pivotal studies in 2022 era readouts, and Kodiak kept running trials while the market moved on. The company now plans a Q4 2026 BLA for Zenkuda spanning three indications, wet AMD, diabetic retinopathy, and retinal vein occlusion, supported by five positive Phase 3 studies (DAYBREAK, DAYLIGHT, GLOW1, GLOW2, and BEACON).

The commercial question is interval economics. Aflibercept 8 mg and faricimab have been fighting over extension to 16 and 20 week intervals. A label built on treat to dryness dosing out to 24 weeks, if the FDA grants it, would make Zenkuda the first anti VEGF agent marketed around a twice yearly maintenance possibility for a majority of patients. That is a payer story and a physician workflow story as much as a clinical one.

What did Mirum’s AZURE-1 trial show for brelovitug in chronic hepatitis delta?

Brelovitug met the primary endpoint at both doses. At Week 24, 56% of patients on 300 mg once weekly and 45% on 900 mg every four weeks achieved combined virologic response and ALT normalization, versus 0% of delayed treatment controls (p<0.0001 for both comparisons).

Mirum Pharmaceuticals reported topline results from AZURE-1, the Phase 3 study of brelovitug, a subcutaneous single agent for chronic hepatitis delta virus, the most aggressive form of viral hepatitis. The trial enrolled 153 treatment naive patients globally, randomized 2:2:1, including patients with advanced disease.

The primary endpoint combined virologic response (at least a 2 log10 reduction in HDV RNA or undetectable HDV RNA) with ALT normalization. Safety was clean: zero Grade 3 or higher or serious adverse events in either treated arm and zero discontinuations, with treatment related adverse events of 23.7% on weekly dosing and 33.8% on the every four weeks schedule. The only Grade 4 event in the study, a myocardial infarction, occurred in the untreated delayed arm.

Mirum plans a BLA submission in the first half of 2027 and a potential US launch in Q4 2027. Trade coverage framed brelovitug as a commercially differentiated challenger to Gilead’s bulevirtide, approved in Europe, and to Vir Biotechnology’s clinical stage combinations (per Fierce Biotech). Note the dose response direction: the weekly arm outperformed the monthly arm by eleven percentage points. Convenience has a price, and Mirum now has the data to argue the weekly schedule is the one worth taking.

MIRM closed at 87.96, down 1.9%, in what was a double first reaction session: the Atebrioz FOP approval crossed at Friday’s close and the AZURE-1 win landed Monday morning. We do not assign a cause to the fade; the stock had run ahead of both events.

What is AstraZeneca’s $2 billion investment in Summit Therapeutics?

AstraZeneca is buying $2.0 billion of newly issued Summit preferred stock, convertible into roughly 12.0% of Summit’s outstanding common shares, alongside a clinical collaboration combining Summit’s ivonescimab with AstraZeneca’s antibody drug conjugates. The announcement came after Monday’s close.

Summit closed Monday at 15.48, down 0.8%, before the news; Tuesday is the first reaction session. The structure is notable for what it is not: no license, no milestones, no royalty. AstraZeneca bought equity in the US rights holder of Akeso’s PD-1/VEGF bispecific while ivonescimab sits weeks from its November 14 FDA decision, and pointed its ADC portfolio at combination regimens on top of it.

What did the FDA approve Juvmo (tavapadon) for in Parkinson’s disease?

The FDA approved AbbVie’s Juvmo (tavapadon), a once daily selective D1/D5 dopamine receptor agonist, for Parkinson’s disease in adults, covering both monotherapy in early disease and adjunct use with levodopa in patients with motor fluctuations. US availability is expected in October 2026.

AbbVie’s chief scientific officer called it “the first dopaminergic breakthrough for Parkinson’s disease in decades.” The existing D2/D3 agonist class carries sedation and impulse control baggage that has limited use; tavapadon’s D1/D5 selectivity is the differentiating claim, though its label still notes hallucinations, orthostatic hypotension, dyskinesia, and impulse control disorders as risks.

ABBV closed at 266.28, up 0.7%, on approval day.

Why did Merck and Daiichi Sankyo withdraw the ifinatamab deruxtecan filing?

The companies voluntarily pulled the US accelerated approval application for ifinatamab deruxtecan (I-DXd), a B7-H3 directed antibody drug conjugate, in previously treated extensive stage small cell lung cancer after the FDA told them the Phase 2 dataset fell short of accelerated approval requirements.

The filing rested on IDeate-Lung01, a 187 patient Phase 2 study whose response data the companies had called promising. According to the partners, the FDA concluded “the data supporting the application falls short of the level needed to meet the requirements for accelerated approval,” and Merck’s Marjorie Green said the company was “disappointed that the current dataset are not supportive of an approval at this time” (per Fierce Biotech). Phase 3 IDeate-Lung02 is nearly enrolled, leaving a resubmission path with randomized data.

It is the second regulatory blow to the collaboration under which Merck paid Daiichi Sankyo $4 billion upfront in 2023 for three ADCs: patritumab deruxtecan drew a manufacturing rejection in 2024 and was withdrawn in 2025 after a failed confirmatory trial. The read for the field is that the FDA keeps raising the bar on single arm accelerated approvals in tumors where randomized options exist, a bar this same agency articulated all year across oncology advisory committees.

Separately Monday, Merck licensed SPR2015, a preclinical oral KRAS G12D inhibitor, from Shanghai based SciBrunch for $400 million upfront and up to $2.13 billion total (per Fierce Biotech). A preclinical Chinese asset commanding a nine figure upfront is itself a data point in the China licensing cycle we have tracked all year.

Why did Roche drop its muscle sparing obesity antibody?

Genentech discontinued emugrobart, an anti myostatin antibody meant to preserve muscle during GLP-1 driven weight loss, after a Phase 2 interim analysis in the Gyminda trial concluded success was unlikely. Chugai regains the program.

Emugrobart had already failed to move muscle endpoints in spinal muscular atrophy and facioscapulohumeral muscular dystrophy earlier in 2026, so the obesity discontinuation completes a pattern rather than starting one. Genentech said the antibody “did not consistently deliver the hoped-for improvements in muscle growth and function.” The muscle preservation thesis remains one of obesity’s most crowded follow on categories; the field’s proof burden just went up, and every myostatin program pitching a combination with incretins now carries this readacross.

What happened at EASD 2026 on day one, and what reads out this week?

Day one in Milan carried no major sponsor readouts; the heavy data land Tuesday through Thursday. The day one item of note was industry infrastructure: Dexcom published its State of Type 2 report on global access to diabetes technology.

Dexcom’s survey of more than 800 health care professionals and 2,500 people with type 2 diabetes across eight countries found 89% of clinicians say continuous glucose monitoring helps them assess adherence between visits, while 55% of patients report limited knowledge of CGM, and 58% of GLP-1 users pair CGM with their medication versus 27% of non insulin users (per the report). The gap between clinician conviction and patient awareness is the commercial map for the CGM category’s next leg.

Viking Therapeutics closed at 33.03, down 7.1% and now 5.6% below its $35.00 offering price from last week’s upsized raise (our arithmetic against the disclosed offer price), a repricing into the week’s readouts. We assign no cause.

What happens when pharmaceutical tariffs take effect on September 29?

Tuesday is the general effective date for Section 232 tariffs on patented pharmaceutical imports: a default 100% rate for importers without trade agreement coverage or an approved onshoring plan, with reduced tiers of 20% for Commerce approved onshoring commitments, 15% for the EU, Japan, South Korea, Switzerland, and Liechtenstein, and 10% for the UK (per trade counsel summaries of the proclamation).

Generic drugs remain excluded, with the Bureau of Industry and Security directed to revisit that carve out within a year. Seventeen named large companies have already been paying since July 31 under the proclamation’s accelerated schedule. The practical questions for operators start Tuesday: customs classification of API versus finished form, the paperwork burden of proving onshoring plan coverage, and whether the 20% tier functions as intended industrial policy or simply as a smaller tax. We will report observed effects, not predictions, as they surface.

What else happened on September 28?

Three items worth the log. SCYNEXIS won a BARDA contract worth up to approximately $214 million if all options are exercised, with an $18.5 million base period, to carry SCY-247, a second generation oral and intravenous antifungal, through NDA submission for treatment and prevention of invasive fungal infections; non dilutive government money for antimicrobial development remains the exception, not the rule, which is why it is news. Tolerance Bio signed a thymus focused pact with Mitsubishi Tanabe worth up to $560 million (per Fierce Biotech). And Adicet Bio reported lupus remissions from an early stage trial of its allogeneic gamma delta CAR T candidate (per Fierce Biotech), another data point for off the shelf cell therapy in autoimmune disease.

Which biotech stocks moved on September 28, 2026?

Moves that carry a story, from exchange settled closes:

Frequently asked questions

Did Kodiak’s DAYBREAK trial succeed?

Yes. Both Zenkuda (tarcocimab tedromer) and KSI-501 (tabirafusp alfa tedromer) met their primary endpoints, delivering vision gains non inferior to aflibercept at one year in treatment naive wet AMD, per Kodiak’s September 28, 2026 release.

How often can Zenkuda be dosed?

In DAYBREAK, Zenkuda was dosed on an individualized schedule of every 4 to 24 weeks after four monthly loading doses, and 54% of patients reached a six month interval at year one under strict fluid based retreatment criteria.

When will Kodiak file for FDA approval of Zenkuda?

Kodiak plans a BLA submission in Q4 2026 covering wet AMD, diabetic retinopathy, and retinal vein occlusion, supported by five positive Phase 3 studies.

What is brelovitug and how well did it work?

Brelovitug is Mirum’s subcutaneous single agent for chronic hepatitis delta. In Phase 3 AZURE-1, 56% of patients on 300 mg weekly and 45% on 900 mg every four weeks achieved combined virologic response and ALT normalization at Week 24, versus 0% of controls.

When could brelovitug reach the US market?

Mirum plans a BLA submission in the first half of 2027 and has targeted a potential US commercial launch in Q4 2027.

Why did Mirum stock fall despite the AZURE-1 win?

MIRM closed down 1.9% at 87.96 in the first session after both the Atebrioz approval and the AZURE-1 readout. We do not assign a cause; the stock had appreciated substantially into both events.

How big is AstraZeneca’s stake in Summit Therapeutics?

AstraZeneca is investing $2.0 billion in newly issued preferred stock convertible into roughly 12.0% of Summit’s outstanding common shares (10.6% fully diluted), with closing anticipated within a week of September 28, 2026.

What will AstraZeneca and Summit study together?

The named collaboration combines sonesitatug vedotin, a Claudin-18.2 ADC, with ivonescimab in gastrointestinal cancers, with a memorandum of understanding covering broader combinations of ivonescimab with AstraZeneca cancer medicines including additional ADCs.

What is Juvmo (tavapadon) approved for?

Juvmo is approved for Parkinson’s disease in adults, as once daily monotherapy in early disease and as adjunct to levodopa in patients with motor fluctuations. AbbVie expects US availability in October 2026.

Why was the ifinatamab deruxtecan filing withdrawn?

The FDA told Merck and Daiichi Sankyo that the Phase 2 IDeate-Lung01 dataset fell short of accelerated approval requirements in previously treated extensive stage small cell lung cancer, and the companies voluntarily withdrew the application pending Phase 3 data.

What pharmaceutical tariffs start September 29, 2026?

Section 232 tariffs on patented drug imports reach their general effective date: 100% by default, 20% with an approved onshoring plan, 15% for the EU, Japan, South Korea, Switzerland, and Liechtenstein, and 10% for the UK. Generics are excluded for now.

What data comes at EASD 2026 this week?

CagriSema REIMAGINE 1 body composition Tuesday; retatrutide TRIUMPH-2, SURPASS-CVOT, and the OCTANE Wegovy pill switching study Wednesday; Foundayo ACHIEVE-4 cardiovascular safety and the oral semaglutide STEP UP liver analysis Thursday.

Did anything else notable happen after Monday’s close?

AstraZeneca submitted a US NDA for ORPATHYS (savolitinib) plus TAGRISSO (osimertinib) in MET driven EGFR mutated lung cancer based on the Phase 3 SAFFRON trial, which HUTCHMED said hit both progression free survival and overall survival; detailed figures come at ESMO 2026.

Sources

Primary sources (September 28, 2026): Kodiak Sciences DAYBREAK topline press release; Mirum Pharmaceuticals AZURE-1 topline press release (investor relations site); AstraZeneca press release on the Summit Therapeutics equity investment and collaboration; AbbVie press release on the FDA approval of Juvmo (tavapadon); SCYNEXIS press release on the BARDA contract; HUTCHMED press release on the US NDA submission for ORPATHYS plus TAGRISSO; Dexcom State of Type 2 report announcement.

Trade press and other coverage (September 28, 2026): Fierce Biotech (Merck/Daiichi I-DXd withdrawal; Merck/SciBrunch license; Roche emugrobart discontinuation; Kodiak and Mirum coverage); Medical Daily (EASD 2026 week schedule); trade counsel summaries of the Section 232 pharmaceutical tariff proclamation. Closing prices from exchange settled data.

Related coverage

Read our Monday briefing on the IMS myeloma data, the four approval Friday, and Novo’s Nanexa delivery deal, our Friday briefing on GRAIL’s post panel session and Viking’s $500M raise, and our coverage of GRAIL’s advisory panel votes.