I do not see why adding to Philip Morris's competitive advantage should have any bearing on what Congress does. That is, as long as the law would do what it is meant to, it should not matter if it helps one tobacco company over others.
Presumably, the regulations passed would be intended to reduce the amount of smoking that happens in the United States. This is really all that we should care about. It should not matter if one tobacco company has an advantage over the others -- all that should matter is that smoking be reduced and, thereby, the health problems that come with smoking.
Laws should be enacted on the basis of their contribution to enhancing the public good. These laws may affect affect, individuals and companies differently, but as long as fundamental rights of the people are not violated, general public good must take preference over considerations of advantage or disadvantage of public companies.
Further, if the law favours a company companies which because their operations are more compatible with the public good, then there is all the more reason for enacting law.
The question does not clarify what kind of regulation of tobacco product is envisaged, and how it will benefit Phillip Morris. But if Phillip Morris is benefited, for example, because it sells products that are less harmful to health, then there is no justification for grudging their added advantage.