BOSTON (TheStreet) -- More controversy among the Duchenne muscular dystrophy stocks kicks off this week's Biotech Stock Mailbag.

Steven M. asks, "Adam, what do you think of Biomarin Pharmaceuticals(BMRN) - Get Report and PTC Therapeutics(PTCT) - Get Report working together to promote their [Duchenne muscular dystrophy] drugs at a joint meeting?"

It's weird, somewhat inappropriate and definitely risky for Biomarin given its DMD drug drisapersen is currently under FDA review. Sarepta Therapeutics(SRPT) - Get Report is also excluded from the event, of course.

If you're unsure what Steven is referring to, Biomarin and PTC Therapeutics are co-sponsoring an investor "symposium" on June 22 in New York City titled, Advances in Duchenne Muscular Dystrophy Natural History and Biomarkers.

According to email that the companies sent to analysts and investors, the event will "review the latest research on DMD, including natural history data, clinical biomarkers, and imaging assessments used in monitoring disease progression and response to therapy. An overview of state-of-the-art therapies in development will be discussed."

PTC and Biomarin will be speaking about their respective DMD drugs, ataluren and drisapersen, of course. The agenda includes presentations by DMD experts Drs. Craig McDonald, Perry Shieh and Lee Sweeney. Pat Furlong, president of Parent Project Muscular Dystrophy, a patient advocacy group, is also speaking.

I can't recall an instance where two companies -- potential competitors -- co-sponsored an investor event. For Biomarin, the event smells like a pre-approval promotional effort for drisapersen, which risks angering FDA as the agency begins the drug review process. Biomarin CEO J.J. Bienaime has learned little from the mistakes made by Sarepta's former CEO Chris Garabedian, apparently.

I'm not privy to the specific content for the event, but it will be interesting to hear how Sarepta's eteplirsen is characterized during the "state of the art therapies" portion. Too bad Sarepta wasn't invited by PTC Therapeutics and Biomarin to help educate investors. Will eteplirsen be mentioned at all?

And what will PTC and Biomarin say about clinical biomarkers given that their respective regulatory strategies rely on FDA ignoring clinical biomarkers? Only Sarepta has data connecting its drug's efficacy with important clinical biomarkers.

By participating in this event, PPMD's Furlong is lending credence to the claims from some parents in the DMD community that she is working actively to keep eteplirsen from getting approved.

Biomarin spokesperson Debra Charlesworth says the June 22 event with PTC Therapeutics is part of the company's regular investor outreach program and is not meant to promote drisapersen inappropriately while the drug is under FDA review.

PPMD spokesman Will Nolan says Furlong "has been asked to discuss risk/benefit -- what it means to patients/caregivers... Pat's presentation is not intended to encourage or persuade investors in any way."

Celgene's(CELG) - Get Report decision to license a single CAR-T therapy target from Bluebird(BLUE) - Get Report and return the other drug target candidates seems like a minor disappointment for Bluebird but nothing grave. Investors are excited about Bluebird for its gene therapy pipeline. The cancer immunotherapy CAR-T stuff, including the collaboration with Celgene, was always secondary.

I do wonder if Celgene is sending a hint to the market that it doesn't believe in the long-term success of CAR-T therapies. Writing a check for $25 million to Bluebird for a CAR-T target in multiple myeloma is an inexpensive way for Celgene to potentially expand or defend its most important cancer franchise. Think of it as a CAR-T call option.

But given the opportunity to invest heavily and more broadly in CAR-T, Celgene steps back. Is that decision a function of Celgene concern with Bluebird's technology, alone? Or, does it suggest Celgene looked closely at the  CAR-T field overall and came away believing that ongoing intellectual property uncertainty, manufacturing concerns, pricing issues and problematic safety don't add up to a profitable, long-term business.

If the latter is true, pure-play CAR-T stocks Juno Therapeutics (JUNO) , Kite Pharma (KITE) , Ziopharm(ZIOP) - Get Report and others are at potentially greater risk. So far, the market disagrees. Juno, in particular, was up 11% Thursday, a day after the Celgene-Bluebird announcement. The alternative-alternative explanation for Celgene stepping back from Bluebird is because the company wants to go with Juno CAR-Ts. We'll see.

Chill out. Celldex Therapeutics(CLDX) - Get Report is down about 10% since the start of the ASCO annual meeting last Friday. That's not surprising given the stock's 15% to 20% run up into the cancer conference. The value of Celldex shares has increased more than 80% since last November when the interim results from the Rintega "ReACT" study were announced.

Celldex assumes an incidence of 4,000 GBM patients with the EGFRvIII mutation in the U.S. The company offers no insight on price but I'll assume Rintega costs $100,000 per year. That's a potential $400 million market opportunity for Celldex. Let's say Celldex treats 60% of those patients three years after Rintega's launch in 2016. That's $240 million in Rintega sales by the end of 2019. What's that worth today? At a 6x multiple discounted back 15%, you get a net present value of $760 million.

Celldex's market value today is $2.6 billion.

I like Celldex. I am not arguing Celldex is over-valued. Celldex can seek Rintega's approval in Europe -- larger GBM patient population but lower price, so let's say call it even and estimate another $700 million in present value. That gets us to $1.5 billion. The company is also developing a broader pipeline of cancer immunotherapies. But when you say you're flummoxed because Celldex has traded lower despite very positive clinical data presented at ASCO this weekend, realize that the company's valuation baked in a lot of good news. It's up to you as investor to figure out how much the rest of Celldex is worth.

Puma Biotech(PBYI) - Get Report was a $60 stock last July when the neratinib extended adjuvant "ExteNet" breast cancer study hit its primary endpoint. If Puma fails to secure approval for neratinib in the extended adjuvant breast cancer setting, the stock should fall back to $60 or even lower. Puma is a one-drug company: neratinib or bust.

After this weekend's downbeat presentation of data from the ExteNet study, the risk that neratinib busts is raised significantly. Even with Puma's stock down substantially since last Friday, the market is still not fully recognizing the risk that FDA either refuses to let Puma seek approval of neratinib or rejects the drug after it is filed and reviewed.

The ultimate goal of Puma CEO Alan Auerbach is to sell the company. You can't rule out a sale, but given what we learned this weekend, it's really difficult to conjure a scenario in which a right-thinking corporate board approves an expensive acquisition of Puma without a much clearer regulatory and commercial outlook.

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.