Upcoming events – Crucial patent ruling on Copaxone and PDUFA for Parsabiv

Welcome to your weekly digest of approaching regulatory and clinical readouts. Much attention is focused on the inter partes review (IPR) decision on Teva’s Copaxone – news on the patent challenge against the valuable three-times-weekly dosage is due to emerge by August 25th, but could come any day now.

And by August 24 Amgen will hear from the FDA about approval of its Sensipar follow-on, Parsabiv. A head-to-head study showed the product to be differentiated, but safety signals emerged.

Valuable opportunity

Teva has five key patents protecting the 40mg version of Copaxone, which several generics firms are hoping to see invalidated. Earlier this week the US Patent Office turned down Mylan’s request to review one of those patents, pushing the legal fight into the courts. A decision over three more, however, is pending.

The IPR process, overseen by the patent office, is intended as a relatively quick assessment of patent validity. The outcome is crucial, however, as it would be very hard for the decision to be ultimately overturned in court.

The three patents concerned are already due to be contested in a court case in September, hence the importance of the IPR decision. While some analysts have picked Mylan to prevail, others believe Teva will emerge victorious – but all agree the case will be close.

The generics giant will appreciate a win – the MS therapy generated more than a third of its sales in 2015, even after the launch of a low-cost competitor to the 20mg, once-daily version in July of that year. The 40mg, three times-weekly version is considered a much more valuable opportunity. Most analysts expect generics to enter the market at some point next year. The question is how early, and the outcome of the IPR will help provide a clearer answer.

Generic challenge

Parsabiv, also known as AMG 416, will have its US fate decided by August 24. It is indicated for the treatment of secondary hyperparathyroidism, a complication of end-stage renal disease. It is Amgen’s follow-on to Sensipar, and as an injectable it falls into the bundled payment system that Medicare has implemented for dialysis patients (Sensipar follow-on will test Amgen's powers of persuasion, August 19, 2014).

On the company’s first quarter call they noted that the Centers for Medicare and Medicaid Services (CMS) have given a two-year period where Parsabiv will operate outside the bundle under the average sales price. This will give the CMS time to decide the value of the bundle once the product is included.

Sensipar, an oral drug, lies outside the scheme and loses patent protection in 2018, so generic Sensipar could present a challenge to the profitability of Parsabiv.

To try and persuade payers that it is worth it, Amgen completed a head-to-head study against Sensipar last year. The 683-patient trial met its primary endpoint on non-inferiority. 68% of patients receiving Parsabiv achieved a greater than 30% reduction from baseline in mean parathyroid hormone levels compared with 58% using Sensipar. It also demonstrated superiority with 52% achieving greater than 50% reduction versus 40% of patients on Sensipar.

While Parsabiv differentiated on efficacy its safety profile will be watched closely. There was an increased rate of cardiac failures with Parsabiv compared with Sensipar at 3.0 and 0.6%, respectively. Also fatal events were seen in 2.7% of Parsabiv and 1.8% of Sensipar patients.

According to consensus from EvaluatePharma 2022 sales are forecast to reach $423m. Sensipar’s forecast sits at $442m in 2022, just a third of the $1.4bn it sold last year.

Product Trial details Trial ID
Parsabiv (vs Sensipar)
(paediatric study)
NCT01896232
NCT02341417

To contact the writers of this story email Joanne Fagg or Amy Brown in London at news@epvantage.com or follow @JoEPVantage or @AmyEPVantage on Twitter

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