The Access to Medicine Index identifies GSK, J&J and Sanofi as the companies doing most to make their drugs available and affordable in poorer countries.
Better pricing deals and development of drugs for neglected diseases are among the areas of company activity praised by the report, but the management of drug trials in developing companies is criticised.
GSK, which topped the Index in 2010, remains in front though its overall rating is only slightly higher. J&J and Sanofi have significantly improved their ratings.
The major Japanese firms are bottom of the league, as well as being absent from such initiatives as the WHO campaign to fight neglected tropical diseases.
In its third year, the Netherlands-based Index notes that companies are showing better internal organisation in relation to drug access issues.
Of the 20 largest pharma companies, 17 have improved access to their drugs in the developing world since 2010: they are developing more relevant drugs and doing more to facilitate patient access to them.
In particular, more companies are using tiered pricing schemes to make products more affordable for certain countries or population groups – most notably Gilead, whose HIV drugs are used worldwide.
However, the Index states that companies could do more to support generic versions of their drugs and adapt drug packaging to local needs.
It also notes that the outsourcing of clinical trials to Contract Research Organisations lacks transparency and control, with only four companies (GSK, Sanofi, Eisai and Merck & Co.) saying they enforce ethical codes.
Wim Leereveld, CEO of the Index, said: “Access to medicine is a multi-faceted challenge and the pharmaceutical industry has a critical role. While it has made strides in many areas, companies that have sector-leading practices also show us there is more the industry can contribute.”