Zevra Therapeutics (ZVRA), a company focused on rare diseases, might be sitting on a potential gold mine, and surprisingly, it's not the drug everyone is watching. While all eyes are on the potential approval of Arimoclomol for Niemann-Pick Disease Type C (NPC), a closer look at the Q1 2024 earnings call transcript reveals a fascinating development with OLPRUVA, a treatment for urea cycle disorders (UCDs), that seems to have slipped under the radar of most analysts.

The initial launch of OLPRUVA began in January 2024. It entered a market dominated by RAVICTI, a drug notorious for its high price and challenging palatability. OLPRUVA, however, boasts a significantly lower cost and a formulation designed to overcome the taste and smell issues associated with other sodium phenylbutyrate treatments.

While Zevra reported only four new patient enrollments for OLPRUVA in Q1, the transcript hints at a much more compelling story unfolding beneath the surface. The company emphasizes that the four enrollments represent only 'new patients eligible for benefits investigation or our Quick Start program,' indicating a potentially larger pool of patients already prescribed OLPRUVA but not yet categorized as 'enrollments.'

Furthermore, Zevra's Chief Commercial Officer, Josh Schafer, reveals a crucial detail: '...there are more than [four] currently on OLPRUVA who have been prescribed OLPRUVA.' This statement, coupled with the rapid growth in reimbursement coverage from 55% to 75%, suggests a quiet yet significant adoption of OLPRUVA is underway.

Here's where it gets interesting. Zevra acknowledges that 'de minimus' OLPRUVA sales in Q1 were due to pre-existing inventory at specialty pharmacies. This implies minimal shipments were needed in Q1 because pharmacies were already stocked, likely due to a surge in prescriptions towards the end of 2023.

This leads us to a compelling hypothesis: Could Zevra be experiencing a stealth launch of OLPRUVA? While investors are preoccupied with Arimoclomol, a wave of patients dissatisfied with RAVICTI might be quietly switching to OLPRUVA, a phenomenon not fully reflected in the Q1 numbers due to the lag in revenue recognition.

The UCD market in the U.S. is estimated at approximately $350 million annually. If Zevra is capturing even a modest portion of this market with OLPRUVA, the revenue potential could be substantial.

Potential Revenue Scenario for OLPRUVA

Consider this: Let's assume Zevra manages to achieve a 20% market share by the end of 2024, a conservative estimate given the positive feedback on OLPRUVA's palatability and cost advantage. This translates to a potential revenue of $70 million for OLPRUVA alone.

Moreover, Zevra anticipates authorized generics of RAVICTI entering the market in late 2024. While this might appear as competition, Zevra views it as an entry into the 'higher end of the market,' leaving OLPRUVA well-positioned to dominate the 'off-price' segment.

Zevra is playing a clever game. While orchestrating a high-profile campaign for Arimoclomol, it's simultaneously executing a silent yet effective launch of OLPRUVA. This strategic approach not only maximizes their chances of success with both drugs but also creates a powerful 'one-two punch' in the rare disease market.

Comparing Patient Enrollments and Reimbursement Coverage

Investors focused solely on Arimoclomol might be overlooking a hidden gem in Zevra's portfolio. OLPRUVA, the silent symphony, has the potential to become a blockbuster drug, transforming Zevra into a major player in the rare disease arena.

"Fun Fact: Zevra Therapeutics, formerly known as KemPharm, changed its name in February 2023. The new name, inspired by the zebra, reflects the company's commitment to rare diseases, often characterized by unique and distinct 'stripes' of symptoms."