The variation 1.e4 c5 2.a4 was invented by the American opening theoretician and author Hugh Myers (1930-2008). Myers is best known for his writings on unusual chess openings such as the Nimzovich Defense (1.e4 Nc6). The eccentric opening 1.c4 g5!? is known as Myers' Defense because of his advocacy of it in his writings and games. Myers wrote numerous editions of his book on the Nimzovich Defense, as well as three other books on the openings. He edited and published the Myers Openings Bulletin from 1979–88 and the New Myers Openings Bulletin in 1992–96.
This opening can transpose into the Rossolimo Variation (1.e4 c5 2.a4 d6 3.Nf3 Nf6 4.Bb5+) so it’s not totally bad. Maybe it’s worth looking at if you want to surprise an opponent. At any rate, there is plenty of room for you to do your own research. FM Stefan Buecker has written a brief 8 page pdf book on this line you can download from ChessCafe HERE.