The American Association of Neurology is hosting its annual meeting this week in Washington, DC. Through the end of this week, major biotechnology companies will be making presentations highlighting drug breakthroughs and updates. Analysts at Cowen & Co., led by Ritu Baral, highlighted what to watch for when several companies present at the annual meeting.

Biogen Inc (NASDAQ:BIIB)

Cowen expects Biogen’s presentation at the AAN meeting to garner the highest level of investor focus. Baral expects Biogen to provide incremental data on aducanumab (BIIB037), a drug intended to treat Alzheimer’s disease. BIIB037 slows the growth of amyloid plaque, which is considered to be a primary cause of Alzheimer’s. Cowen expected Biogen to provide an update on the drug’s efficacy and safety profile, and hopefully “shed light on if prodromal or mild patients gained greater benefits.” However, the Cowen team is concerned about data derived from the small placebo group in the trial and is waiting for “longer term data… over the next 1-2 quarters.”

Eric Schmidt of Cowen & Co. currently has an Outperform rating on BIIB with a $500 price target. He has rated Biogen Inc seven times since May 2009 with a 86% success rate recommending the stock and a +18.3% average return per Biogen rating. Overall, Eric Schmidt has an 85% success rate recommending stocks with a +56.6% average return per recommendation.

On average, the top analyst consensus for Biogen Inc on TipRanks is Moderate Buy

PTC Therapeutics, Inc. (NASDAQ:PTCT)

Ritu Baral believes that data from PTCT’s RG7800 will have the most impact on the stock. RG7800 is in Phase 1b/2a trials for the treatment of Spinal Muscular Atrophy (SMA). Analysts at Cowen are “optimistic for Ph1 results.” If the drug is successful and approved, it will be “strong competition” for a drug by Isis Pharmaceuticals currently in Phase 3 testing. Baral concluded, “We think more robust, longer term data on RG7800 SMN2 production and the localization of production (CNS vs systemic) will be key in predicting clinical success in SMA.”

Ritu Baral currently has an Outperform rating on PTCT with a $120 price target. Baral has only provided a Hold rating on PTCT once before in October 2014 so she does not have an average return or success rate for the stock. Overall, Baral has a 50% success rate recommending stocks with a +21% average return per recommendation.

On average, the top analyst consensus for PTC Therapeutics on TipRanks is Strong Buy.

GW Pharmaceuticals PLC- ADR (NASDAQ:GWPH)

GW Pharma will present updated data on Epidiolex, an epilepsy treatment, suggesting that “Epidiolex can effectively and safely reduce seizures in certain forms of refractory epilepsy.” Cowen commented that GWPH shares appreciated by 21% after AAN released this data, indicating that the stock has already benefitted from the new data. Analysts at Cowen concluded, “We continue to think that GW is undervalued for the potential of Epidiolex, and continue to recommend shares.”

Phil Nadeau of Cowen & Co currently has an Outperform rating on GWPH with a price target of $110. He has rated GWPH six times since June 2014 with a 100% success rate recommending the stock and a +49.9% average return per GW Pharma recommendation.  Overall, Nadeau has a 71% success rate recommending stocks with a +34.8% average return per recommendation.

On average, the top analyst consensus for GW Pharma on TipRanks is Strong Buy.

ISIS Pharmaceuticals, Inc. (NASDAQ:ISIS)

ISIS will present its Phase 3 trial design for TTR-Rx, a treatment for neurodegenerative TTR Amyloidosis. Baral noted, “A blinded safety analysis shows the drug to be generally safe and well tolerated, although we will be watching for injection site reaction rates.” Baral will have more insight into the “validity and nuances of the study design” once more measures are taken.

Eric Schmidt of Cowen & Co currently has an Outperform rating on ISIS though he does not have a price target on the stock. He has rated ISIS three times since November 2012, earning a 100% success rate recommending the stock and an overwhelming +153.5% average return per Isis Pharma recommendation.

On average, the top analyst consensus for Isis Pharma on TipRanks is Hold.