From the old ADOX website:

"+++ PAN 400 is ready for production but due to the sudden changes at Fotokemika who manufactured the CHS line of films for us we had to prioritize and decided to invest in the remanufacturing of a 100 ASA material at first+++ "

That's why there is a no Adox Pan 400.But they gave us the ADOX CHS 100 II instead.
As long as Kodak floods the market with cheap TRI-X there will be no new 400 ASA film from any manufacturer.

Cheers
Wolfgang