PDP was a brand, not a manufacturer. They made their name by working with a couple of US manufacturers to offer good quality racquets through the mid '70s, most notably the aluminum "OPEN" made famous by Tanner (developed by Maark Corporation, which also produced the original aluminum Prince) and the 100% fiberglass "Fiberstaff" (made by Starwin Industries). The brand was eventually sold to Le Coq Sportif (at which point Tanner also switched to LCS, for a big increase in endorsement pay, according to his autobiography); LCS was itself owned by Adidas.
As most US-based racquet brands began offshoring their production to Taiwan in the early '80s, PDP (LCS/Adidas) tried to do the same, but that effort seemed rather short-lived, as the brand basically vanished altogether not too long after that. Yours is probably the result of one of those final gasps, likely not much later than 1983 by the looks of it. The Deniau endorsement could have had something to do with the brand's LCS ties.
A rare and interesting find indeed, especially given its extremely unusual specs! Too bad you don't seem to have learned much from its original owner.