The data is good news for the 1 million diagnosed patients in the U.S. and Europe and for shareholders eager to see apremilast win market share in the multibillion dollar immunology market.
Currently, there is no cure for psoriatic arthritis.
Since there isn't a cure for psoriatic arthritis, treatment is focused on controlling inflammation to manage the joint pain caused by the body's immune system attacking healthy tissues.
Typically, patients are referred to a rheumatologist who prescribes anti-inflammatory drugs such as Advil and disease modifying drugs - also referred to as DMARDs - which limit the amount of joint damage.
But, DMARDs are often slow acting and the most commonly prescribed DMARD -- Trexall, or methotrexate - may cause serious side effects affecting lung, kidney and liver function.
In more severe case, immunosuppressants and TNF alpha inhibitors, such as Abbvie's (ABBV) Humira and Amgen's (AMGN) Enbrel, are prescribed. However, those drugs may present more serious risks and some patients recoil at the drugs' self-injected dosing.
As a result, apremilast may win share thanks to oral dosing and potentially less severe side effects.
Given apremilast's safety profile, it appears the drug has a good chance of winning approval from the FDA and EMA and gaining share as a bridge between prescribing DMARDs and biologics. The drug was submitted for approval to both agencies this year.
In November, Celgene reported data from its Palace-1 phase III study, showing the drug met its endpoints for both efficacy and safety.
The Palace-1 participants had all previously failed 1-3 DMARD or biologic treatments, yet 50% of those in the monotherapy group saw improvement of at least 20% versus placebo when taking the 30 mg dose of apremilast.
Most recently, Celgene also reported data from Palace-4, the first phase III apremilast trial studying the drug in patients who had not been previously treated with DMARDs. This trial also met its endpoint of a 20% improvement in symptoms.
Importantly, the most common side effects were nausea, diarrhea and headache.
The data suggest oral apremilast could become a first line treatment for severe cases, providing an alternative to biologics including Humira, Enbrel and Johnson & Johnson's (JNJ) Remicade, which is given by infusion.
Apremilast's market opportunity could be $300 million a year.
The mass appeal of the drug and its commercial viability was dealt a blow last summer when it failed to meet endpoints in treating rheumatoid arthritis.
This means the drug won't topple blockbusters Humira, which racked up over $2 billion in global sales in Q1, Enbrel, with Q1 sales of $1 billion or Remicade, with $969 million in sales last quarter.
However, it does mean apremilast stands a good shot at making important headway for psoriasis and psoriatic arthritis patients. This market opportunity has analysts expecting apremilast may generate sales of $300-500 million a year.
Since the apremilast phase III studies remain ongoing, any additional data demonstrating efficacy and safety could help sales rise considerably beyond those expectations.
As for investors curious whether now is a good time to buy Celgene, the market has tended to embrace biotechnology stocks through the summer conference season. Celgene is no exception. According to the Seasonal Investor database, shares have gained ground in 7 of the past 10 years during the three months ending July.
Given the strong seasonality and potential apremilast catalyst, now may be a good time for investors to consider Celgene for portfolios.