>>189
入れ子を考慮すると反復しないと無理ぽ、考慮しないなら>>187ので動く
Dim str As String = "<a><a href="".."">松井玲奈</a></a>　と　<a href="".."">仁藤萌乃</a>　が　<a href="".."">大好き</a>　です"

Dim result As String = Regex.Replace(str, "\s", String.Empty)
Dim pattern As String = "<a[^>]*>(?!.*<a[^>]*)(.*?)</a>"
Dim m As Match = Regex.Match(result, pattern)

While (m.Success)
　　result = result.Substring(0, m.Index) + m.Groups(1).Value + result.Substring(m.Index + m.Length)
　　m = Regex.Match(result, pattern)
End While

Console.WriteLine(result)