The JPL Mountain Bike Duathlon was a race that combined a 5K running course with a 7K uphill mountain biking course. This race has only been held once, in 1990.
Another Bike & Run event was held once in 1986. This was a "cooperative biathlon" that featured teams of two athletes sharing one bicycle. The objective was for both team members to share the bicycle and arrive back at the finish line at the same time.
Some information is linked below. Additional information will be posted as it becomes available.