Surface Logix Inc. padded its Series D financing round with an additional $20 million tranche, twice what was expected when the initial investment closed.

The additional $20 million, added to the $32 million raised in October 2005, brought the Series D round to $52 million. The initial financing contemplated an additional $10 million investment if certain milestones were reached. (See BioWorld Today, Oct. 31, 2005.)

"The data from our programs continue to be very good," Warwick Tong, senior vice president, commercial development at Surface Logix, said of the new investment. "The extra tranche means we can do more in the next phase of development."

Proceeds from the financing will be used to begin three Phase IIa trials of the Boston-based company's two lead products, all expected to get under way this quarter.

The company was founded in 2000 and began development operations in June 2003. It has raised about $92 million in three venture rounds and an angel financing. It said its chemistry-based discovery approach based on Pharmacomer technology allows it to better control interactions between small molecules and the biological large molecules found in the human body. That is designed to produce compounds with improved pharmacokinetic and pharmacodynamic properties, or toxicity profiles.

Since the 2005 funding, the company has completed a Phase IIa trial of SLx-2101 and a Phase I trial of SLx-4090. The new money is expected to see Surface Logix through the upcoming Phase IIa trials.

The lead product candidate is SLx-2101, a selective, fast-onset phosphodiesterase-5 inhibitor believed to have an effect for 48 hours, longer than that claimed by existing PDE-5 inhibitors such as the approved erectile dysfunction drugs Viagra and Cialis (which claims a 36-hour duration of action). The initial Phase IIa trial of the compound demonstrated positive results in erectile dysfunction.

But the plan going forward is not for the ED market, Tong said. The ED trial was designed only to prove the concept.

"From a commercial development point of view, the ED market is a relatively well-satisfied market," Tong told BioWorld Today. "This program was started with the idea that there was a real opportunity for PDE-5 inhibitors in cardiovascular disease that had not been [addressed]. Our intention was always to take our PDE-5 program to cardiovascular diseases."

Surface Logix said it intends this quarter to begin Phase IIa trials of SLx-2101 in both hypertension and Raynaud's syndrome, a condition that affects blood supply to the fingers, toes and occasionally the ears and nose.

SLx-4090 is an enterocyte-specific microsomal triglyceride transfer protein (MTP) inhibitor that is in development for treatment of dyslipidemia and familial hypercholesterolemia. It is designed to prevent formation of chylomicrons, which are used to transport triglyceride and cholesterol into the systemic circulation. The approach is expected to address the liver toxicity seen in other compounds from the MTP-inhibitor class.

Phase I studies of SLx-4090 demonstrated reductions in post-meal triglyceride and LDL levels, as well as tolerability, the company said.

The Phase IIa trial of SLx-4090 expected to begin this quarter will be in dyslipidemia patients with high triglyceride levels.

Tong said all three Phase IIa trials are expected to be completed by the end of the year. The company is not talking much beyond that about plans beyond that.

The next pipeline program at Surface Logix, SLx-2119, is designed to inhibit the ROCK2, or Rho-associated kinase 2, signaling pathway. The lead indication appears to be in oncology, though the anti-angiogenesis class of compound also is believed to have promise in inflammatory and fibrotic diseases.

None of the programs at Surface Logix is partnered. Tong did not identify that as a priority. "We have interesting data," he said. "If [potential partners] are interested in talking to us, we will talk with them."

Participating in the financing round were current investors Venrock Associates, ARCH Venture Partners, CW Group, HBM BioVentures, Unilever Technology Ventures and others.