Vertex said in its second-quarter earnings call that its HCV marketing expenses will remain substantially reduced through the second half of 2013. In the same breath, the biotech said its specialty HCV sales force, which it continues to see as a “good investment,”  will remain in place through the launch of its all-oral HCV contender, VTX-135, despite news of a partial clinical hold on Phase II trials and dwindling revenues from older hep. C med Incivek.

Sales of the needle-based protease inhibitor, which declined by 52% vs. the prior-year period, stands as a stark reminder that the firm needs to refresh its hep. C portfolio. Many patients are waiting for a new wave of oral HCV meds to arrive, and Vertex had been in the mix of competitors. That is, until a recent speed bump on all-oral HCV contender VTX-135.

Vertex confirmed that it received notice from FDA for its on-going Phase II trial. The partial clinical hold will stall evaluation on its 200mg dose until the effect on liver enzymes in patients can be better understood. Vertex plans to submit this data to regulators by the fourth quarter of this year. The hold has no bearing on studies of VTX-135’s 100mg dose, Vertex said.

Vertex’s HCV candidate is at best third in the all-oral arms race with Gilead’s sofusbuvir and AbbVie’s five-drug cocktail as the clear frontrunners

A silver lining for the company came by way of its new cystic fibrosis treatment Kalydeco, which doubled revenues due to strong sales in Europe. Kalydeco brought in $99 million for Q2 2013 vs. $45.5 during the same three months  last year.

The drug maker also announced results from a Phase III Kalydeco crossover study that showed “significant improvements in weight gain and quality of life,” in patients during trials. Based on that data, Vertex plans to file a supplemental NDA in Europe and the US for Kalydeco for use in people over the age of six who have at least one non-G551D GFTR gating mutation.

Vertex hiked its full-year forecast, due to Kalydeco’s impressive showing for the quarter, upping its estimates from $1.1-$1.2 billion to $1.10-$1.25 billion for the full year.

Total Vertex revenues for the quarter fell by $310 million, or 26%. The company mitigated its losses by narrowing its cost and expenses to the tune of $367.78—a drop of 14% compared to last year.