BOSTON ( TheStreet) -- Oncothyreon ( ONTY) was the runaway stock-performance winner of ASCO '15.
Between May 12 and June 3, Oncothyreon's stock price rose 183%, best among all the companies presenting cancer drug research at the American Society of Clinical Oncology annual meeting. Oncothyreon's presentation of early-stage data on breast cancer drug ONT-380 was well received but investors were probably more enamored with the company's relatively low valuation.
I chose this 16-day trading period to track stock performance because it begins with the public release of ASCO research abstracts on May 13 and ends the day after the meeting concluded.
Puma Biotech ( PBYI) was the worst-performing biotech and drug stock during the ASCO period, falling 28% due to the underwhelming efficacy and high rate of side effects seen with the company's breast cancer drug neratinib.
Ignyta RXDX and ImmunoGen ( IMGN) were the other big ASCO winners, returning 93% and 61%, respectively.
Turning to Big Pharma, it's fair to say Bristol-Myers Squibb ( BMY) received the most media coverage for its cancer immunotherapy drugs Opdivo and Yervoy, but some of the data presented didn't sit well with investors because the stock lost almost 3% during the ASCO performance period.
None of the Big Pharma stocks moved all that much, but Abbvie ( ABBV) and Roche ( RHHBY) emerged as winners with stocks each moving 3% higher.
This year's ASCO meeting didn't feature much new data from the CAR-T stocks, but Juno Therapeutics ( JUNO) had enough to move the stock 25% higher.
Among mid- and large-cap biotech stocks, Seattle Genetics came out on top with a 14% return.