Sell-side analysts, briefed by the CEO of Puma Biotechnology (PBYI) , offered different, conflicting stories to downplay the surprise exit of the company's head of regulatory affairs right before the FDA and outside experts review the breast cancer drug neratinib.

Puma disclosed the resignation "for health reasons" of Dr. Robert Charnas, Senior Vice President, Regulatory Affairs, in an 8-K filed Thursday night. Puma shares dropped 13% overnight on fears Charnas' exit signaled more bad news ahead for neratinib, which has already been tarnished by middling efficacy and an alarming propensity to send women to the hospital with raging diarrhea.

According to Puma, Charnas submitted his letter of resignation on April 28. His last day will be May 15, which is nine days before the May 24 neratinib FDA advisory panel.

That's a bad look. So, of course, sell-side analysts rushed to Puma's defense. But they told conflicting stories, which only adds to the uncertainty surrounding Charnas' departure.

Credit Suisse analyst Alethia Young spoke to Puma CEO Alan Auerbach on Thursday night. She has an outperform rating on Puma. In her published report, Charnas' exit has nothing to do with neratinib's chance in front of FDA advisory panel. Instead, Charnas leaving Puma was the result of "negative interactions" with other Puma employees that were "jeopardizing the team's ability to function."

Did Charnas really resign for health reasons? He claimed illness in his resignation letter but that might have just been due to the stress of being forced out of Puma. "It's a little confusing," writes Young, "but it seems that it was the lawyers' decision based on the resignation letter."

Citi analyst Yigal Nochomovitz also spoke with Puma's CEO. In his note, Nochomovitz insists the market has "completely misinterpreted" Charnas' departure, which was a totally benign event due to health reasons that have nothing to do whatsoever with neratinib.

If Auerbach told Nochomovitz that Charnas was having problems with his fellow Puma employees, it's not mentioned in his report. "Buy on free dip," Nochomovitz advises.

It's the FDA's practice to send companies a copy of the briefing book for a drug advisory committee 14-21 business days ahead of the scheduled meeting. Importantly, this briefing book includes the FDA's internal medical review of the drug.

Since Puma's neratinib advisory committee meeting is on May 24, the FDA could have sent the neratinib review to the company as early as April 25 or as late as May 4, yesterday.

Puma claims Charnas submitted his resignation letter on April 28, or conceivably, after he had read the FDA's neratinib review.

Puma denies having a copy of the FDA briefing book on neratinib, according to the analysts who spoke with Auerbach. But for that to be true means the FDA is late sending the neratinib briefing book to Puma.

Auerbach did not respond to an email seeking clarifications.

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Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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