I'm currently looking for a job in pharma-biotech industry. What is the normal path to contact them? I've noticed people is normally not listed in their company webpages.
Short answer: You don't :)
It's not people you need to look for on their company web pages, but rather any job postings. If there are roles available and you get far enough, then you'll be contacted by the relevant people. Remember, there's a reason why they don't list contact details for these people on their websites, which is to prevent them being overwhelmed by potential candidates pestering them about jobs.
These organisations don't just create jobs for the "right" person, the role must exist first based on what they perceive to be a business need. So while perusing their web pages is the right place to start, focus on the "Jobs" section rather than contact details.