BOSTON ( TheStreet) --The Biotech Stock Mailbag Readers' Portfolio (BSMRP) nears the halfway point of the year still underwater and trailing the performance of the broader biotech sector.

The BSMRP, a portfolio of 20 biotech and drug stocks chosen by readers of my weekly Biotech Stock Mailbag, is down 11% this year compared to an almost 3.5% loss in the benchmark iShares Nasdaq Biotechnology ETF. (Performance is tracked through the close of trading on June 11.)

A series of unfortunate events earlier in the year (read: drugs blowing up in clinical trials and negative FDA approval decisions) have contributed mightily to the BSMRP's lackluster performance. More recently, the portfolio has suffered as the overall markets turned south and seasonal selling of biotech stocks accelerated.

For those that might have forgotten, the BSMRP was down 8% compared to a 9% gain in the benchmark when I last did a performance check in late April. So, in two months, the BSMRP slid a bit further, but not nearly as bad as the broader biotech sector.

No portfolio should ever be completely static, so a refresh of the BSMRP is in order. I'm going to "sell" the three worst performing stocks -- GenVec ( GNVC) (down 72%), Cell Therapeutics ( CTIC - Get Report) (down 61%) and Novelos Therapeutics ( NVLT.OB) (down 93%).

I'd like to remove two additional stocks from the BSMRP to make room for new (and hopefully better-performing) companies. Mannkind ( MNKD) should exit, perhaps? Or how about Titan Pharmaceuticals ( TTNP.OB)? Both are also performing poorly, the former because of delays to the approval of its inhaled insulin device; the latter due to the slow launch of the schizphrenia drug Fanapt.

Neither China Medical Technologies ( CMED) nor Allos Therapeutics ( ALTH) seem to be generating much investor interest, so perhaps one or both should be booted from the BSMRP? Or I could remove Celldex Therapeutics ( CLDX - Get Report), which no longer occupies the minds of traders now that the American Society of Clinical Oncology annual meeting is behind us.

In terms of replacement stocks, this is a readers' portfolio, so I look to you for new recommendations. Please email me with replacement stock picks at adam.feuerstein@thestreet.com. Please send your email with BSMRP in the subject line along with a few-sentences reason for including your stock pick(s) in the revamped portfolio. Delcathians can skip that last part, I know why you want Delcath ( DCTH) in the BSMRP.

The BSMRP is in a hole partly because readers loved risky small-cap biotech stocks a bit too much. These volatile investments are great when the market is hot, but knowing when to exit before the small-caps cool off or blow up is key. So few of these stocks ever really pay off long term, which makes them great trading vehicles. As investments? Not so much.

Let's talk about what's working well in the BSMRP and give readers kudos for picking some hot stocks.

The top performer to date -- and the biggest turnaround story -- is Keryx Pharmaceuticals ( KERX). At our last update in April, Keryx was trading flat, but in two months, the stock soared 46% thanks to excitement about its cancer drug perifosine.

Ariad Pharmaceuticals ( ARIA) continues to post strong returns, up 44.5%, while Vivus ( VVUS - Get Report) is now up 31%. Vivus' obesity drug Qnexa faces a pivotal FDA advisory panel review in July, which will trigger volatility in the stock, one direction or the other, depending on the panel's recommendation.

Seattle Genetics ( SGEN - Get Report) has moved up nicely in the BSMRP performance rankings. Later in the year, the company will announce results from a pivotal study of its drug SGN-35 in patients with Hodgkin's lymphoma.

Dendreon ( DNDN) also continues to outperform, although perhaps not a much as some investors would like, on the recent Provenge commercial launch.

The summer months are slow times for biotech, which often means a lot of stocks go on sale from lack of interest. That makes this a compelling opportunity to refresh the BSMRP with new stocks that can push returns into the green once the fall rolls through.

Please send me your new stock picks!
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-- Reported by Adam Feuerstein in Boston.

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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.