What happened

Amgen (AMGN -1.01%) shares were trading 6.8% lower late Wednesday following a second-quarter earnings beat that was marred by lowered full-year guidance.

So what

The biopharma outfit turned $6.5 billion worth of sales into per-share earnings of $4.38 for the three-month stretch ending in June, both up from year-ago figures, and both topping consensus estimates. Analysts were only modeling a profit of $4.09 per share and revenue of $6.46 billion.

But the challenges created by the pandemic linger. The company lowered its per-share guidance for 2021 to a range of between $8.84 and $9.90, according to generally accepted accounting principles (GAAP), down from prior guidance of between $9.11 and $10.71 per share, as, according to executive vice president Murdo Gordon, "patient visits and lab test procedure trends continue to improve but remain below pre-COVID-19 levels." Fewer doctor-patient visits crimps sales of Amgen's drugs like migraine treatment Aimovig, psoriasis drug Otezla, and arthritis drug Enbrel.

A lab technician working on a pipette.

Image source: Getty Images.

Now what

The market's response to contracted guidance is understandable, but perhaps unmerited. Amgen shares have already been a subpar performer of late, currently trading where they were as of November 2019, and now back to breakeven for the year. Most of the company's prospective challenges were already baked in.

Given this context -- coupled with the fact that Amgen still boasts one of the better portfolios in the pharmaceutical business -- Wednesday's stumble is arguably more of a buying opportunity than a hint of what the future holds. The current dividend yield of 2.9% is also uncharacteristically high for the industry, bolstering the bullish argument. Buyers just need to be prepared for continued volatility.