Vertex Pharmaceuticals' $4.9 billion purchase of Alpine Immune Sciences probably won't be the last acquisition of a company focused on kidney disease.The biotechnology industry is getting more attention than usual following a buyout offer for Alpine Immune Sciences (ALPN -0.05%) from Vertex Pharmaceuticals (VRTX -0.92%).Vertex recently offered Alpine Immune Sciences $65 per share, or about $4.9 billion in cash. On April 9, the day before the announcement, Alpine's stock price closed at about $39 per share.G ...