A pharmaceutical company reported that its new drug showed a statistically significant reduction in symptoms compared to a placebo in a…

The first sentence reports a positive, statistically meaningful result; the second sentence introduces a qualification that complicates how meaningful that result actually is in practice. That shift from "significant" to "questionably noticeable" is a contrast, which however signals. Therefore would frame the second sentence as a consequence of the first, but physicians' doubts don't follow logically from a significant result, they push back against its practical importance. Similarly would suggest agreement between the sentences, not the tension actually present. For instance would frame the second sentence as an example of the first's claim, not a complication of it.