While the biotech tape remains a challenging one, Maxim analysts remain positive on drug maker Keryx Biopharmaceuticals (NASDAQ:KERX) and gene-therapy-product maker bluebird bio Inc (NASDAQ:BLUE). Below are the ratings along with current price targets and comments from lead analysts Jason Kolbert and Jason McCarthy.

Keryx Biopharmaceuticals

Maxim analyst Jason Kolbert reiterated a Buy rating on shares of Keryx, while slashing the price target to $5.00 (from $11.00), after the company released fourth-quarter results. Specifically, the company reported Auryxia US revenues of $4.8 million, compared to $3.1 million in the prior quarter, which could be considered as incredibly slow.

Kolbert observed, “We are reducing our price target after making adjustments for guidance to $5.00 from $11.00. Auryxia sales guidance is for 3% market share in 2016 and $31-$34M in sales. Cash expenses are guided to $87-$92M. Reimbursement levels remain at aprox. 65%. Keryx closed the quarter with $200M in cash on the balance sheet and did say that they believe the current cash balance will support the company through to break-even.”

The analyst continued, “Auryxia sales continue to creep forward from $1.7M, $3.1M to $4.8M in the current quarter sequentially. How is that possible in a billion dollar marketplace? We do believe that Auryxia is a best in class drug and that is the fundamental element of our thesis. Anemic sales makes us question what are we missing but KOL feedback remains, “best in class”. Clearly other factors (mature market), managed care, physician comfort, patient awareness are contributing to the slow launch.”

According to TipRanks.com, which measures analysts’ and bloggers’ success rate based on how their calls perform, analyst Jason Kolbert has a yearly average return of -19.7% and a 26.3% success rate. Kolbert has a -54% average return when recommending KERX, and is ranked #3662 out of 3666 analysts.

bluebird bio Inc

In addition, Maxim’s Jason McCarthy reiterated a Buy rating on shares of bluebird bio with a price target of $105, following the company’s fourth-quarter financial results and update on its pipeline.

McCarthy wrote, “bluebird continues to drive multiple programs forward in both immune oncology and gene therapy. Near-term catalysts are on the horizon in the less-talked-about gene therapy program in childhood cerebral adrenoleukodystrophy (CCALD), which, if positive, are significant both for bluebird and the gene therapy space. Data from the Starbeam study will be presented at the American Academy of Neurology meeting in April 2016. bluebird will present more long-term data at the actual conference than are expected to be seen in the abstract (release date in early March). We also expect updates from the CAR-T program and the initiation of additional beta thalassemia studies (i.e., HGB-207).”

According to TipRanks.com, analyst Jason McCarthy has a yearly average return of -20% and a 20% success rate. McCarthy has a -51% average return when recommending BLUE, and is ranked #3597 out of 3666 analysts.

Out of the 10 analysts polled by TipRanks (in the past 3 months), 6 rate bluebird bio stock a Buy, while 4 rate the stock a Hold. With a return potential of 85.65%, the stock’s consensus target price stands at $88.