What happened

Shares of the clinical-stage cell therapy company Adaptimmune Therapeutics (ADAP -0.56%) were down by 9.1% as of 2:37 p.m. ET on Wednesday. Earlier today, the biotech's shares were down by an unsightly 12.5% at their low point.

So what

Investors appear to be throwing in the towel on Adaptimmune stock today for three reasons:

  1. ImmunoGen's (IMGN) antibody-drug conjugate mirvetuximab posted strong late-stage results in advanced ovarian cancer yesterday. Adaptimmune appears to have designs on this same indication after an early-stage trial for its SPEAR T-cell therapy ADP-A2M4CD8 yielded encouraging results. 
  2. December is the last month for investors to shed their losers for tax-loss harvesting purposes. Adaptimmune, for its part, has had a rough year, with its shares down by over 30% year to date.
  3. Sentiment across the biopharma industry has turned decidedly negative over the prior two months. Adaptimmune's stock appears to be getting swept up in this downward trend.   
A person staring at a red arrow breaking through a floor.

Image source: Getty Images.

What's truly remarkable about this latest double-digit move lower is that Adaptimmune has had nothing but success in the clinic this year. In fact, the biotech is expected to file its first regulatory application for afamitresgene autoleucel as a treatment for advanced synovial sarcoma or myxoid/round cell liposarcoma, two forms of cancer, next year. 

Now what

Is Adaptimmune's stock worth picking up at these levels? Although market sentiment toward biotech is overwhelmingly negative at the moment, Adaptimmune still comes across as a screaming buy after this downturn. It has a strong chance of becoming a commercial-stage company next year, and it has multiple high-value partnerships in play. Aggressive investors, in turn, might want to take advantage of today's weakness.