Prothena's Psoriasis Candidate Disappoints In Phase I Study

Prothena Corporation plc (NASDAQ:PRTA) announced results from a phase Ib multiple ascending dose (MAD) study of pipeline candidate, PRX003 in psoriasis patients. The primary objectives of the study were achieved. However, advancing PRX003 into mid-stage clinical development required a well-defined relationship between biological activity and meaningful clinical effects and these prerequisites were not met.

The study enrolled 33 patients with psoriasis and was designed to assess the safety, tolerability, and pharmacokinetics of PRX003. PRX003’s impact was evaluated through multiple exploratory endpoints of pharmacodynamic activity. These included assessing CD146 occupancy and downregulation, efficacy evaluations of psoriasis severity as measured by PASI 75 response rates, and histopathologic and RNA transcript assessment of skin biopsies to examine changes in cytokines that are known markers of inflammation.

While PRX003 administration resulted in dose- and time-dependent occupancy and downregulation of CD146 on Th17 cells, consistent with prior Phase Ia SAD study results, the pharmacodynamic effects did not translate into meaningful clinical benefit for psoriasis patients treated with PRX003, as measured by responses in the Psoriasis Area and Severity Index 75 (PASI 75).

Moreover, skin biopsy data demonstrated insufficient reduction in measurements of Th17 cell infiltration and other inflammatory markers required to advance PRX003 into mid-stage clinical development for psoriasis or psoriatic arthritis as previously planned.

As a result of failed data on PRX003, Prothena will focus on advancing NEOD001 (phase IIb and phase III), PRX002 (phase II) and PRX004 (expected to enter Phase 1 by mid-2018).

The results surely disappointed investors, as Prothena does not have any lead drug in its portfolio.

Prothena’s stock has moved up 31.7% in the year so far compared with the industry’s gain of 17.8%.

We expect investors’ focus to remain on further updates from its late-stage candidate, NEOD001.

Meanwhile, Prothena has a license agreement with Roche Holding (SIX:ROG) AG (OTC:RHHBY) for the development and commercialization of selected antibodies targeting alpha-synuclein including PRX002. The collaboration not only boosts Prothena’s pipeline development but also provides funds in the form of research reimbursement and milestone payments.

Under the agreement, the company received upfront payment of $30 million in January 2014. In addition, the initiation of a phase I study on PRX002 allowed the company to receive a clinical milestone payment worth $15 million.

The collaboration agreement with Roche, which is a leader in the oncology space, is a big positive for Prothena. The company initiated a phase II study, PASADENA, on PRX002 for patients suffering from Parkinson`s disease which triggered a $30 million milestone payment from Roche to Prothena.

Zacks Rank & Key Picks

Prothena currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the health care sector are Regeneron Pharmaceuticals, Inc. (NASDAQ:REGN) and Aduro Biotech, Inc. (NASDAQ:ADRO) . While Regeneron sports a Zacks Rank #1 (Strong Buy), Aduro carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.

Regeneron’s earnings per share estimates have increased from $12.84 to $14.99 for 2017 and from $15.32 to $16.65 for 2018 over the last 60 days. The company delivered positive earnings surprises in two of the trailing four quarters, with an average beat of 10.11%. The share price of the company has increased 17.9% year to date.

Aduro Biotech’s loss per share estimates narrowed from $1.46 to $1.36 for 2017 over the last 30 days. The company delivered positive earnings surprises in two of the four trailing quarters with an average beat of 2.53%.

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