IMO it's because no one really knows who Pulmatrix is as a company. Most stock owners are not the general public. Likewise, people don't understand the value of an inhaled anti-fungal however, they need look no further than Acorda (ACOR) Therapeutics who is being very successful thru their inhaled version of an old (generic) Parkinson's drug. I would buy PULM and not look at it again for 18-24months...if their clinical trial goes well, you're a hero...if not, well you just have to get out.
My understanding is that Concert was able to procure the IP for a deuterated version of Kalydeco years ago it is unclear if Concert can do this again for Orkambi or other CF related compounds. I think Vertex has improved their IP protection from deuterium-modified versions of their compounds. Worth mentioning is that CEO @ Concert Pharma was instrumental in the success of Kalydeco for Vertex years ago.
Our DD has been on Orkambi for 75 days, the only initial side affects were some chest tightening and a few days of increased mucus production. This is the longest she's gone without antibiotics in 3 years.