To say "most big pharma labs" do not have access to the literature is laughable. We had better access than most academic institutions. If we needed a paper we didn't have access to, it took a few hours to get it. The company was more than willing to pay the $50 to get a copy of whatever paper, since we would often blow $50 running one experiment. Many of the smaller biotech might have poor access to journals, but even then, if you could justify the cost, you could get it.
Second of all, yes I trust labs that are trying to recreate data to make a drug out of it. You have to remember that these attempts to recreate data were a very important data point on a potential multi-million (billion?) dollar investment in a new target, these are NOT low priority projects. They WANT the data to be true. They have zero incentive for the data to not be reproducible.
Having worked in both academic and commercial labs, I would say the incentive to "tweak" results in much great in academic labs for the following reasons:
1) Often results are never double checked in an academic lab unless the work is use in a later project. Contrast this with a pharma lab where if the data is positive, you'll have to prove it again and again. 2) Academics (both profs and students) live and die by papers, not so in academic (in fact, in the company I worked in, they preferred if you didn't publish) 3) Work in academic is often performed by relatively inexperienced ungrad and grad students, while big pharma scientists often have years of experience.