They haven't sold anything. Go to SEC filings on NWBO webpage and find the latest form SC-13 from Woodford, it's dated Jan 10th. It discloses ownership of 25M shares of common stock. If they sold a portion of it they would need to file an amended form with SEC.
Woodford owns 24,815,028 shares per the 10K, so depending upon when those shares were valued at mark to market, the value of his holdings could be less than $5 million. So it's very possible that number represents less than 1% of the PC fund. (That fund probably has close to $1 billion in assets under management.)