BioBoyScout

$ARWR trades at over $10B today. If ARO-MAPT's Phase 1 reads positive in 2H 2026, the math says it's worth $55-$90B to a strategic acquirer. Not a guess. Four independent methodologies. Same range. Full paper: drive.google.com/file/d/1D5eD6Y…

The Acquisition of the Decade. In chess, the queen is the most powerful piece on the board. $ARWR is the queen of biotech M&A this decade. The four arguments inside my latest note. bioboyscout.com/p/the-acquisit…

@ArrowheadPharma @LABJnews Well-deserved. Eighteen years building one of the most strategically important platforms in biotech. Congratulations, Chris!

Once again, our CEO Chris Anzalone, PhD was recognized in the LA500 as one of the most executives in Los Angeles. Congratulations, Chris and thank you to @LABJnews labusinessjournal.com/la500-2026/hea…

@BiotechTV Great points from Luca. Worth noting that $ARWR's TIDES data answered the last open preclinical question on ARO-MAPT, and the structural advantage over BIIB080 is the subQ delivery and uniform brain distribution. Detail: bioboyscout.com/p/aro-mapt-the…

𝐑𝐁𝐂 𝐆𝐥𝐨𝐛𝐚𝐥 𝐇𝐞𝐚𝐥𝐭𝐡𝐜𝐚𝐫𝐞 𝐂𝐨𝐧𝐟𝐞𝐫𝐞𝐧𝐜𝐞: RBC Capital Markets Senior Analyst Luca Issi shares his take on biotech and comments on key companies he covers that have been in the news. $IONS $ARWR $RGNX $QURE Full video: biotechtv.com/post/rbc-healt…

New paper: The Acquisition of the Decade. Which pharma acquires $ARWR will own the most strategically important asset in biotech this decade. Why, and at what cost of not acting. bioboyscout.com/p/the-acquisit…

@mabioinvest @tanavoi373 3/3 The alternatives would predict uniform results across doses. Biogen specifically reported the lowest dose produced superior cognitive benefit while biomarker effects were comparable. That requires dose-related safety differentiation, which the SAE data shows. Not hand-waving.

@mabioinvest @tanavoi373 2/3 Tau saturation explains comparable biomarker effects across doses but not why the lowest dose produced superior cognitive outcome. That requires safety differentiation at higher doses, which is what Biogen reported (higher SAE at highest dose). SubQ avoids the bolus issue.

WOW! $BIIB's CELIA validates the tau hypothesis. Robust biomarker reductions plus cognitive signals in randomized Phase 2 = first clinical proof tau-targeting works. The primary endpoint miss and inverse dose response actually strengthen the case for $ARWR's ARO-MAPT.

@JamesMclaw70633 Yes, broadly. Tau-lowering works on normal tau production in any brain. Late-2026 healthy volunteer CSF tau reduction should be comparable to diranersen's ~60% in AD patients. Tau PET reduction would be measured later in AD patient cohorts where tangles exist.

@BioBoyScout Question: Should tau protein reduction be expected to be the same in healthy volunteers as in Alzheimer’s patients with ARO MAPT

New note: ARO-MAPT: Proof of Mechanism $BIIB CELIA validated the tau hypothesis. Mechanism works. Bear case answered. $ARWR's ARO-MAPT now sits with structural delivery advantages and proof of mechanism in hand. bioboyscout.com/p/aro-mapt-pro…

@tanavoi373 Yes, that's the structural advantage. Tau is produced throughout the brain, but AD pathology starts in deep regions (hippocampus first) that intrathecal delivery can't reach effectively. ARO-MAPT distributes evenly across the brain, exactly where the disease lives.

@BioBoyScout since aro-mapt can reach the deep brain, especially the hippocampus where the tau protein is created, is this why it strenghtens the case for aro-mapt?

12/12 Three numbers from Phase 1/2a will tell us if ARO-MAPT translates: CSF tau needs ~50%+ (BIIB080 hit ~60%) Plasma p-tau217 needs to move Tau PET directional reduction is enough Hit all three → re-rating event. No cognition data needed. Full note: bioboyscout.com

11/12 Competitive read: Biogen's BIIB080 (CELIA Phase 2 reads out this year) also lowers tau. Gets credit for proof-of-concept. But BIIB080 needs a spinal tap. $ARWR's own data shows spinal-tap drugs can't reach the deep brain regions where tauopathies live.

1/12 Quick thread on $ARWR's TIDES presentation yesterday on ARO-MAPT, their Alzheimer's drug. Most of the deck has been public since last September. But two new data points closed the last open question on the preclinical case. Here's what they mean: