D. J. Bernstein
Fighting patents

US patent 5848159, Collins Hopkins Langford Sabin, RSA with several primes

Text of the patent
No reports of enforcement attempts.

At first (and second) glance, nothing new. The original RSA patent already mentions using several primes:

In alternative embodiments, the present invention may use a modulus n which is a product of three or more primes (not necessarily distinct).
Not worth a closer look unless there are enforcement attempts.