On 3 April, at the American College of Cardiology Scientific Sessions, BridgeBio presented an interim analysis of the long-term outcomes from the Phase II open-label study of acoramidis in patients diagnosed with transthyretin amyloidosis cardiomyopathy (ATTR-CM). The median time since Phase II enrollment was 38 months and long-term treatment with acoramidis was generally well-tolerated and resulted in a median decline in NT-proBNP levels, normalisation of serum TTR, and sustained stabilisation of TTR in individuals with symptomatic ATTR-CM. Further evaluation in a Phase III trial is ongoing, with month 30 topline data expected next year.
Acoramidis, an orally administered small molecule transthyretin, is currently being assessed in Phase II and Phase III trials in patients with ATTR-CM and ATTR-polyneuropathy (ATTR-PN). There is currently only one approved therapy to treat ATTR-CM, Pfizer’s Vyndaqel, which was approved in 2018. Acoramidis will be fighting for a share of the ATTR cardiomyopathy population, currently dominated by Pfizer’s Vyndaqel, which has been instrumental in driving disease awareness and increasing the diagnosis rate of ATTR-CM.
Prior to the approval of Vyndaqel, there was no targeted treatment for ATTR-CM and, as a result, physicians had no incentive to push for an ATTR-CM diagnosis. As many early symptoms of amyloidosis can be difficult to differentiate from other disease states, diagnosing patients at an early stage is an obstacle faced by many clinicians. ATTR-CM patients were seeing an average diagnosis timeframe of 8.6 years, at which point almost 50% would already be under cardiac care. This previous symptomatic care can also be an issue as many cardiology drugs can cause an exacerbation of ATTR symptoms and lead to a clinical worsening of the associated cardiomyopathy. Now, pathways for the diagnosis of ATTR-CM have become more streamlined with the use of technetium pyrophosphate scanning and a lack of contraindications. Industry and academia have also collaborated on increasing awareness of ATTR through research, therapeutic development and advertising.
Despite Vyndaqel’s efficacy and availability, its high price point is a major barrier to treatment access and it has a significant co-pay, making it unaffordable for many patients. Due to the age demographics of ATTR-CM patients, many physicians are opting out of Vyndaqel treatment to avoid placing the stress of payment on their patients.
In addition to its efforts in ATTR cardiomyopathy, acoramidis is set to be the only oral drug approved in the US for ATTR polyneuropathy, as Vyndaqel has failed to gain approval by the US Food and Drug Administration (FDA) for this indication so far. As acoramidis will likely see approvals in both polyneuropathy and cardiomyopathy, this provides a greater opportunity for pricing contracts to be negotiated with payers as acoramidis will be able to treat a larger patient population than Vyndaqel. In addition, according to key opinion leaders interviewed by GlobalData, acoramidis, while beneficial in a similar way to Vyndaqel, looks like it may be more potent than tafamidis. But due to Vyndaqel’s dominance in the space, acoramidis would likely benefit from a head-to-head study.
There will also be strong competition between acoramidis, Alnylam Pharmaceuticals’ vutrisiran, and AKCEA’s second-generation RNA-targeted therapy AKCEA-TTR-LRx, which are all striving for approvals in both ATTR-CM and ATTR-PN. On 4 April, the FDA extended the NDA review timeline for vutrisiran to allow for the review of newly added information related to the new secondary packaging and labelling facility. The Prescription Drug User Fee Act (PDUFA) goal date to allow for this review for ATTR-PN is 14 July this year. AKCEA’s second-generation RNA-targeted therapy AKCEA-TTR-LRx is still in Phase III development. Both are administered subcutaneously, but vutrisiran is administered every three months, making it more appealing than AKCEA-TTR-LRx, which is administered every four weeks. Despite this, the oral administration of acoramidis is a strong benefit and will increase compliance significantly in ATTR patients.
A strong move from BridgeBio and its partner companies would be to have the company engage in disease awareness and patient services, as seen by its main competitors. The pipeline for ATTR is growing quickly and although this brings new hope to the disease area, real-world data and long-term efficacy data are still in progress. Companies will need to differentiate their therapies from Vyndaqel and, in turn, the launch of additional therapies will greatly impact Vyndaqel’s patient share and pricing strategy.