Public anger over drug prices finally seems to be catching up to the pharmaceutical industry.

Earnings reports in recent days have laid out a grim picture of slumping sales and anemic growth projections at several large manufacturers and wholesalers. Executives blame many factors — including heavy competition and insurers’ hardball tactics — but analysts say the message is clear: Pharma can no longer count on steadily hiking drug prices.

That realization has sent some drug stocks on a roller coaster. It’s also battering middlemen in the prescription supply chain, who make their money by taking a cut of ever-rising prices.

“This is the first quarter where drug pricing showed up in black and white numbers, on income statements and on balance sheets, and was an unmistakable factor in actual earnings,’’ said Brad Loncar, a biopharma investor who runs a cancer immunotherapy fund.

Pressure to hold the line on prices is most acute in the market for drugs to treat chronic diseases, like diabetes, multiple sclerosis, and rheumatoid arthritis. There’s big demand for such treatments, but there are a lot of competing products.

The fallout has been evident in third-quarter earnings reports.

Consider Amgen, one of the nation’s largest biotechs, based in Thousand Oaks, Calif. Its blockbuster drug Enbrel, which treats inflammatory diseases like psoriasis and rheumatoid arthritis, is facing “volume decline due to increased competition,’’ Anthony Hooper, an executive vice president at Amgen, said in a conference call.

Amgen had relied on increasing prices to make up for falling sales. But on the call, executives said they would have to focus instead on boosting demand. That’s a tough path, considering that Enbrel competes directly with AbbVie’s Humira, the top-selling drug in the world.

Amgen’s stock tumbled 10 percent last Friday on the news, and continues to trend downward. Not that AbbVie has been doing much better: The company also took a stock hit when it said its sales had slowed.

Biogen, based in Cambridge, faces a similar struggle: It acknowledged last week that it had relied “primarily’’ on price increases to keep revenue from its multiple sclerosis drug Tecfidera rising. Executives said the company now plans to focus aggressively on growing its market share, even though the overall market for multiple sclerosis drugs in the United States isn’t expanding.

Another example: The share price for McKesson Corp., a massive wholesale drug distributor, dropped a stunning 26 percent on Friday on fears that drug price hikes would slow — and so would revenue for the middlemen who get those drugs to consumers.

McKesson said there now are “fewer products with price increases,’’ and even when they have gone up, the hikes were more modest than in the past. It projected increases for the upcoming year “to be meaningfully below’’ last year’s numbers.

McKesson’s stock price is slowly rebounding. So are the shares of two other drug wholesalers whose stock dropped last week, AmerisourceBergen and Cardinal Health. But analysts don’t expect a period of calm.

“The stocks have had virtually unprecedented volatility,’’ said Geoffrey Porges, a biotech analyst at Leerink. “These are stocks that were sort of the heart of many people’s defensive portfolios. To have them down even 5 percent is painful — and 10 percent is unthinkable.’’

Public pressure to bring down prices — and the resulting political posturing — is undeniably one factor roiling the industry. Both Hillary Clinton and Donald Trump have called for reforms, lambasting drug makers as greedy. Senator Bernie Sanders has made the topic his personal crusade, taking to the airwaves and to Twitter to blast drug companies.

But some of the most formidable pressure has been exerted through behind-the-scenes lobbying by insurers and the middlemen known as pharmaceutical benefit managers. These entities, called PBMs, work to lower costs for insurers by forcing drug companies to pay up if they want to keep their medications accessible to consumers.

PBMs can, and do, refuse to list certain drugs on their “formularies’’ unless they can collect rebates from the drug makers. And insurance companies won’t cover drugs that aren’t listed.

“Payers are increasingly willing to block access to certain products as a way to drive discounts,’’ said Adam Fein, president Pembroke Consulting, a pharmaceutical economics analysis firm.

This game of hardball inevitably hits drug makers’ bottom lines: Either they give up substantial revenue to pay big rebates and keep their spots on the formularies, or they lose access to large swaths of patients.

Novo Nordisk, for instance, cited pressure from PBMs as one reason for recently cutting its long-term profit growth forecasts, from 10 percent to 5 percent. The Danish company, which focuses on the highly competitive diabetes market, also announced disappointing sales numbers in the United States.

“We’re only just getting into the storm now,’’ Jesper Brandgaard, the company’s chief financial officer, told Bloomberg. “We can’t in any way say that the worst is behind us.’’

Indeed, it’s not just the public, politicians, and PBMs going after pharma companies: Employers are also trying to use their leverage to demand lower prices.

In addition, some doctors are refusing to prescribe pricey new drugs when cheaper ones are available. A new class of cholesterol drugs, for example, was projected to bring in $3 billion a year in worldwide sales. In the past year, however, they have grossed just above $150 million.

One category of drugs that has been relatively insulated from the pricing pushback is cancer treatments. Many are extremely expensive, yet doctors have still been prescribing them and insurers, in most cases, have been paying. But that could change.

“You can bet, over time, insurers will try to control the cost . . . for cancer care, as well,’’ Porges said. “It’s going to be more difficult for payers to get their hands around oncology — but that being said, this is the fastest-growing area of health spending, and they will certainly try to implement ways to control costs.’’

STAT

Meghana Keshavan can be reached at Meghana.­Keshavan­ @statnews.com Follow her on Twitter @megkesh.