Welcome back to a bonus edition of the Biotech Mailbag. Let's get started with an email from Mark S.

"What are your thoughts about the science behind Sequenom's ( SQNM) underlying platform? Is it thought to be valid?"

Sequenom is a crazy story! The stock tanked late last month after the company shocked everyone with an admission that clinical data supporting its prenatal genetic test for Down syndrome was unreliable due to "employee mishandling" of test data.

The commercial launch of the company's SEQureDX test, scheduled for June, has been delayed, four employees who allegedly did the "mishandling" of the data have been suspended, and an independent (although company-directed) investigation is under way.

Moreover, the fallout from Sequenom's blowup hit two big hedge funds really hard.

In the aftermath of all this, Mark asks a great question. I do believe the science underlying Sequenom's genetic test remains valid, which means that there is a way to extract fetal DNA (or RNA) from a mother's blood and determine whether the fetus has Down's syndrome, for instance.

But, and this is a huge BUT, we have no idea whether Sequenom can translate that science into a commercially viable test. We may discover that Sequenom's test is not any more sensitive than the conventional Down syndrome tests available today. We may learn that Sequenom can't actually develop such a test, or that the FDA now wants to approve any such genetic test before it's launched, given all that's happened.

For these reasons, I think Sequenom is a stock to avoid for now. Others, including one significant holder of the stock I know, are sticking with it because they feel that Sequenom's genetic Down syndrome test will be a big commercial success, albeit a delayed one.

A few things have to happen for me to have that level of confidence: I want to read the findings that come out of the company's investigation into the data mishandling. Regardless of who's to blame, I think someone in upper management needs to lose his or her job. Perhaps that's Sequenom's head of R&D, Betty Dragon, or maybe CEO Harry Stylli should accept responsibility for this debacle and resign. Regardless, Sequenom's board has to do some housecleaning.

The independent verification of the SEQurDX test is also crucial. That data comes next year, and it's absolutely more important than any company-sponsored validation data that comes out in the fourth quarter. After all, relying on company data is what got Sequenom in this mess, so only truly independent data gets the company out.

George P. writes in with a bearish view on Vanda Pharmaceuticals ( VNDA - Get Report) after the stock soared last week on the surprise FDA approval of Fanapt, the company's schizophrenia drug.

I wrote a column Monday looking at the upside/downside scenarios for Vanda's stock price moving forward.

To which George P. replied:

"If Vanda Pharmaceuticals is able to find a partner for Fanapt they would get the same 10% royalty as Titan Pharmaceuticals. Since a 25% royalty is already assigned to Novartis and Titan, the best that Vanda could hope for is to get a 10% royalty in a partnering arrangement. That would leave the partner with 65% of the sales and 100% of the expenses. A very borderline proposition for a partner."So, if the best that Vanda can hope for is to get the same 10% royalty that Titan already has locked up, you'd have to be an idiot to pay 12 times the price for a Vanda share that you can buy a Titan share for."

Several readers asked me why I left Titan out of my Vanda/Fanapt coverage. The simple answer is that Titan trades on the Pink Sheets after voluntarily delisting itself last year. The editorial rules at TheStreet.com discourage us from writing about bulletin board stocks.

Rick K. writes, "You should have pulled the trigger on Spectrum Pharmaceuticals ( SPPI - Get Report). Now what?"

Rick is referring to a cautious write-up I gave to Spectrum in my biotech newsletter March 11. Spectrum recently purchased 100% rights to a clinically effective but commercially disappointing cancer drug called Zevalin. Three previous drug companies have tried but failed to turn Zevalin into a commercial success, so now it's Spectrum's turn.

I'm interested in watching how Spectrum performs, especially if the FDA signs off affirmatively on an expansion of Zevalin's label in July. But I'm also a realist and question whether tiny Spectrum can do any better with Zevalin than its previous owners.

With that said, I decided not to add Spectrum to my newsletter's model portfolio on March 11 when the stock was trading at $1.54. On Thursday, Spectrum was closed at $4.07.

As Rick points out, clearly I missed the boat on this one.

I'm not sure how to explain Spectrum's recent run. Insiders have been buying stock, which helps, as is a more general bump in highly speculative biotech and drug stocks recently. It's still too early to judge Spectrum's success with Zevalin.

As for Rick's "Now what?" question, I guess I'd be taking some profits on this recent jump in the stock price but hold onto a position in case the FDA decision on Zevalin in July is positive.

Wayne C. writes, "I am interested in your thoughts on Allos Therapeutics' ( ALTH) new drug application. If I understand it correctly the FDA will make some judgment by May 25. Can you give us semi-new investors the usual process of how a drug comes to market? I think Allos' drug is being fast tracked. What are the differences in policies to do this?"

Allos submitted its cancer drug pralatrexate to the FDA on March 25. The next step is for the FDA to accept the pralatrexate application for review, which usually occurs after 60 days. In Allos's case, that's May 25. That's also Memorial Day, so expect an announcement from Allos on May 26.

Since pralatrexate is a cancer drug, the FDA probably will grant the application a priority, six-month review time. That puts the final approval decision on Sept. 25, or six months from the filing date.

By the way, the FDA typically reviews drugs for non-life threatening diseases on 10-month, standard review cycle.

As for my thoughts on pralatrexate, I like the drug. I think it will be approved, and I also think Allos is a prime candidate for a partnership with and/or a takeover by a larger drug company. Allos was a long stock in my newsletter's model portfolio.

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