Arrowhead Pharmaceuticals (NASDAQ:ARWR) outlined a slate of expected clinical data updates during a discussion at the Leerink Partners Global Healthcare Conference in Miami, with management pointing to multiple readouts concentrated in the third quarter and additional updates expected in the second half of the year.
Multiple clinical catalysts expected in the third quarter
Chief Executive Officer Chris Anzalone said the company expects topline results in the third quarter from SHASTA-3 and SHASTA-4, its Phase 3 studies of plozasiran in the severe hypertriglyceridemia (SHTG) population. He noted the last patient, last visit is scheduled for June, with topline data planned for the third quarter.
A third third-quarter milestone is expected from ARO-MAPT, which the company described as its first central nervous system (CNS) target addressed via a subcutaneous platform. Management said cerebrospinal fluid (CSF) tau data are expected toward the end of the third quarter, and characterized the readout as important both for validating the target and for validating the broader CNS delivery approach.
Obesity and metabolic programs: early signals, more data later
Anzalone said Arrowhead plans updates in the second half of the year for ARO-ALK7 and ARO-INHBE, its first two obesity-related targets. He emphasized that the data disclosed previously were early and based on small numbers, and said more data will help clarify which patient populations and indications the company will prioritize in the future.
Discussing early observations with ARO-INHBE, he cited what he described as “good redistribution of fat” across cohorts and said that in an obese diabetic cohort treated in combination with tirzepatide, the company saw early signals of weight loss. He also highlighted a liver fat reduction signal in that cohort, saying the combination with tirzepatide produced a 76.7% reduction in liver fat after a short period, raising the possibility of a metabolic dysfunction-associated steatohepatitis (MASH) opportunity.
For ARO-ALK7, Anzalone said the program is earlier and lacks a circulating biomarker, requiring fat biopsies to assess knockdown. He said the company has seen what appears to be good knockdown in fat biopsies and described prior animal data as compelling. He added that Arrowhead is no longer certain it will choose only one of the two obesity targets to advance, suggesting both could move forward if distinct populations or indications emerge.
Commercial launch in FCS and planning for SHTG
Arrowhead is currently approved in familial chylomicronemia syndrome (FCS), and Anzalone said the company has seen a “good rapid launch,” faster than expected. He said the company had reported more than 100 prescriptions as of its last conference call and noted early switches from an Ionis product, citing physician interest in activity and safety.
He also argued the clinically defined FCS market may be larger than commonly appreciated, describing the company’s definition as triglycerides above 880 with a history of pancreatitis or abdominal pain, which he said could represent “low tens of thousands” of patients.
Looking ahead to SHTG, Anzalone said Arrowhead expects to file a supplemental NDA in the fourth quarter following the SHASTA-3 and SHASTA-4 readouts. He said payer discussions have begun in an initial, limited fashion given the current FCS-only approval, and described the early commercial focus for SHTG as higher-risk patients, including those with triglycerides above 880 and those above 500 with a history of pancreatitis. He estimated that group at roughly 750,000 to 1 million individuals and said pricing would be oriented to that core population.
Pancreatitis outcomes, liver fat, and dosing considerations
On acute pancreatitis (AP), Anzalone said demonstrating AP improvement is not required for U.S. regulatory approval, where triglyceride lowering is the key endpoint, but he said AP outcomes are likely critical for reimbursement in Europe. He said Arrowhead is “cautiously optimistic” about observing AP risk improvement in SHASTA-3 and SHASTA-4 and noted SHASTA-5 is ongoing as an event-driven study specifically designed to show improvement in AP in a high-risk population.
Addressing investor discussion about liver fat increases observed in an Ionis pivotal study, Anzalone said he does not expect Arrowhead to see a similar effect at its current 25 mg dosing level, adding that the company has not seen increases previously. He argued the effect may be molecule-specific, pointing to other Ionis programs and contrasting Arrowhead’s experience in its ANGPTL3 program (zodasiran), where he said the company has seen decreases in liver fat. He said the company expects to have clarity once SHASTA-3 and SHASTA-4 data are available in the third quarter.
On product form factor, he said Arrowhead uses prefilled syringes for FCS and expects an autoinjector for SHTG. He suggested less frequent dosing could be more meaningful for less symptomatic populations, describing “4x a year administration at home” as potentially advantageous relative to monthly administration, while adding that convenience has not been the main driver of switching in FCS so far, where he said activity and safety have been cited.
Ex-U.S. strategy and platform expansion beyond the liver
Anzalone said ex-U.S. opportunities in Europe and Japan could be significant for plozasiran in both SHTG and FCS, but emphasized that pancreatitis outcomes will be important in those markets. He also discussed the current uncertainty around “Most-Favored-Nation” pricing policy and said Arrowhead believes it may need more control over ex-U.S. pricing than it would have previously, influencing its approach to partnering. He said the company is approved in Canada and China, with China partnered with Sanofi, and said it is not yet approved in Europe but is hopeful for approval within the next “quarter or two.”
On competitive dynamics and longer-term growth, Anzalone emphasized innovation in delivery beyond the liver, stating Arrowhead can target seven cell types and has clinical programs in five of them. He said the company aims to reach a new cell type every 18 to 24 months and highlighted the upcoming ARO-MAPT CSF tau readout as a potential validation of subcutaneous CNS delivery. He also positioned the dimer approach as a differentiator, saying Arrowhead expects its dimer to be regulated as a single entity and describing the PCSK9/APOC3 combination as a test case where “more knockdown” of both targets is viewed as beneficial.
About Arrowhead Pharmaceuticals (NASDAQ:ARWR)
Arrowhead Pharmaceuticals, Inc is a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of RNA interference (RNAi) therapeutics. Since its founding in 2008, Arrowhead has leveraged its proprietary delivery platform—known internally as the Advanced RNAi Compound (ARC) technology—to silence disease-causing genes in patients suffering from genetically defined diseases. The company’s approach aims to offer durable, targeted treatments across a range of therapeutic areas.
The company’s pipeline includes multiple candidates in various stages of development.
