By Blake Ellis and Melanie Hicken, CNN Investigates

(CNN) -- A leading advocacy group for Alzheimer's patients has stopped accepting funding from a Southern California drugmaker following a CNN investigation into the company that sparked a government probe.

The CNN report on Avanir Pharmaceuticals showed that its drug Nuedexta has not been extensively studied among the elderly and may be unnecessary or even unsafe for them. Nuedexta, which treats a rare laughing and crying disorder known as pseudobulbar affect, or PBA, is not approved to treat dementia patients unless they also suffer from PBA. Yet Avanir's financial success has been heavily reliant on elderly patients in long-term care facilities, where experts say PBA is uncommon.

The article identified cases of inappropriate and potentially fraudulent use of the medication, where regulators found that doctors had improperly diagnosed nursing home residents with PBA to justify using Nuedexta to more easily manage patients who are confused, agitated or unruly.

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After CNN's report, the Los Angeles city attorney announced that it was launching an investigation into Avanir, examining whether the company broke state or federal laws in the sale, marketing or prescribing of Nuedexta.

In the wake of that announcement, the Alzheimer's Association -- one of the leading advocacy groups for people suffering from the disease -- said it would no longer accept funding from Avanir, pending results of the city attorney's investigation. Avanir gave the group nearly $200,000 this fiscal year, which the nonprofit said was .056% of its annual revenue.

"We are committed to people living with the disease, and we encourage vigorous review and oversight of companies and prescribers to ensure best practices are followed for those impacted by Alzheimer's disease," the association said in a statement.

Avanir has supported other nonprofits as well, along with medical and educational events hosted by these groups that support greater awareness and treatment for those who suffer with dementia. Last month in Chicago, for example, Avanir was listed as a sponsor and presenter at an educational event hosted by the Alzheimer's Foundation of America, an organization providing education and support to families and caregivers.

The foundation, which said it has received about $60,000 from Avanir over the past two years, declined to say whether it had any concerns about the findings from CNN's report, but it said it stood by the educational programs it offers at its events, noting that Nuedexta is not mentioned in Avanir presentations and that Avanir is one of many financial backers.

The foundation also provided a statement from one its medical advisory board members, Dr. Jeffrey Cummings, who said that the condition Nuedexta is approved to treat -- PBA -- is "an involuntary behavior that afflicts a certain percentage of those with dementia ...The AFA's Educational Conferences provide caregivers an opportunity to understand and recognize it."

Cummings, however, has his own financial ties to Avanir: Between 2013 and 2016, he received nearly $50,000 from Avanir, in the form of consulting and royalty or licensing fees, as well as travel and meals, according to government data. Cummings could not be reached for comment about these payments. He also was the lead researcher on Avanir's study of Nuedexta in Alzheimer's patients with agitation, which included 194 subjects and found that those on Nuedexta experienced falls at more than twice the rate as those on a placebo.

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In a statement to CNN, Avanir said it is currently researching ways to help patients with a variety of neurological conditions, including Alzheimer's disease. "In conducting this research, we also engage regularly with patient advocacy, research, and other health-related nonprofit organizations because they help us learn and better understand patient and caregiver needs. In the pursuit of these efforts, Avanir takes care to comply with the law and regulations of the FDA and other federal and state bodies."

Avanir has said PBA, the condition Nuedexta is FDA-approved to treat, is often misunderstood and can affect people with dementia and other neurological disorders.

Ian Larkin, a research professor at the management school of the University of California, Los Angeles, who studies the marketing tactics used by pharmaceutical companies, said Avanir's ties to nonprofit dementia advocacy groups are "deeply troubling" and represent a conflict of interest. But the relationships are particularly concerning, he said, because Nuedexta has not been approved specifically for Alzheimer's or dementia.

"I'm not surprised Avanir is pursuing these kinds of sponsorships, because we know the legitimacy and conversations [that nonprofits] can bring are valuable to drug manufacturers," Larkin said. "I am surprised that nonprofits are allowing these sponsorships in light of the significant ethical issues raised."

He said companies such as Avanir use respected events and gatherings as a platform for their own product, outside of its strictly regulated marketing and sales efforts.

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A professor of ethics at Harvard Medical School, Eric Campbell, said that many nonprofits have come to rely on funding from drugmakers, and that ethical lines are crossed all the time in the pharmaceutical industry.

"Yes, this is a conflict of interest," he said. "There is not a single aspect of medical practice and medical education in the United States in which drug companies don't have extensive financial relationships aimed exclusively at promoting their products. The marketing plan is money and payments which buys influence, attention and ultimately results in increased sales."

For Avanir, the push in nursing homes has generated significant revenue -- despite how rare experts tell CNN that PBA is in these facilities. Total sales of Nuedexta reached almost $300 million in 2016, with more than half of all Nuedexta pills going to long-term care facilities since 2012.

And much of the money being spent on Nuedexta is coming straight from the federal government, in the form of Medicare Part D prescription drug funding, for people 65 and over and the disabled. In 2015, the most recent year for which data is available, this Medicare program spent $138 million on Nuedexta -- up more than 400% from just three years earlier.

Avanir is linked to the US government in other ways, too, recently sponsoring a summit of top medical experts and researchers, hosted by the Department of Health and Human Services and the nonprofit in charge of fundraising for the National Institutes of Health (NIH), the US government's primary medical research agency.

The Foundation for the NIH said that Avanir contributed "a modest amount" for the summit and was one of a number of financial backers -- none of which were involved in the development of the program. It noted that Avanir was contacted because it is a member of the highly-respected LEAD Coalition (Leaders Engaged on Alzheimer's Disease). LEAD declined a request from CNN for comment.

Avanir is also entering the world of academia. Currently, it is helping to launch an Alzheimer's training program at a New Jersey community college. The one-year "Alzheimer's Journey Coordination Certificate Program" is slated to start next fall at Camden County College and will train students to assist patients and their families with decisions ranging from housing and transportation to medical treatments. A representative from Avanir's parent company sits on the committee that is shaping the curriculum, led by the Rowan University/Rutgers-Camden Board of Governors.

New Jersey Congressman Donald Norcross, who was an earlier supporter of the training program, said he found the CNN's investigation into Nuedexta "deeply troubling." He said the program will be overseen by the joint board and will not include "any education around PBA or Nuedexta."

"It's never appropriate to put profits over people, especially when you're dealing with care for the most vulnerable among us," he said in a statement. "I support a full investigation into this matter and will certainly review the results."

Email Blake Ellis and Melanie Hicken at watchdog@cnn.com.

This story has been updated to reflect the precise percentage of revenue the Alzheimer's Association received from Avanir this fiscal year. This amount was previously stated as less than 1%.