$re = '/^(HORIZON-\S+-[A-Z]\d-\d{2}\S*)(?:\r?\n(?!Opening\b).*)*\r?\nOpening: (\d{2} [A-Z][a-z]{2} \d{4})\r?\nDeadline\(s\): (\d{2} [A-Z][a-z]{2} \d{4}.*)/m';
$str = '
HORIZON-CL5-2021-D1-01
Conditions for the Call
Indicative budget(s) 
Topics	Type of Action	Budgets (EUR million)	Expected EU contribution per project (EUR million) 	Number of projects expected to be funded
		2021		
Opening: 15 Apr 2021
Deadline(s): 07 Sep 2021
HORIZON-CL5-2022-D1-01-two-stage
Conditions for the Call
Indicative budget(s) 
Topics	Type of Action	Budgets (EUR million)	Expected EU contribution per project (EUR million) 	Number of projects expected to be funded
		2022		
Opening: 04 Nov 2021
Deadline(s): 15 Feb 2022 (First Stage), 07 Sep 2022 (Second Stage)
HORIZON-CL5-2021-D2-01
Conditions for the Call
Indicative budget(s) 
Topics	Type of Action	Budgets (EUR million)	Expected EU contribution per project (EUR million) 	Number of projects expected to be funded
		2021	2022		
Opening: 15 Apr 2021
Deadline(s): 19 Oct 2021';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php