Neutrexin (trimetrexate) combined with Leucovorin (folinic acid) is an effective and safe treatment option for people who don’t respond to their first treatment regimen for Pneumocystis pneumonia (PCP), according to a study published in the June 19 issue of AIDS.

Cotrimoxazole (trimethoprim-sulfamethoxazole [TMP-SMX]) is the most effective first-line treatment when people are diagnosed with PCP. Unfortunately, many people have allergic reactions to the SMX component, and up to 49 percent must switch to another treatment regimen. There are several possible options but no consensus on what works best for second-line therapy.

To determine the effectiveness of Neutrexin plus Leucovorin, Charlotte-Eve Short, MD, from the Brighton and Sussex University Hospital, in Brighton, England, and her colleagues examined the medical records of HIV-positive patients diagnosed with PCP at their hospital between 1996 and 2006. Complete data were available for 16 patients. Ten were male, six were female, and CD4 counts ranged from 6 to 195. All of the patients had failed Cotrimoxazole treatment. People started second-line treatment with Neutrexin and Leucovorin about 16 days after they initiated their first regimen, and the combination was given for an average of 18 days.

Though five people experienced side effects—including anemia and skin rashes—none had to discontinue Neutrexin and Leucovorin because of them, Short’s team found. In terms of effectiveness, 71 percent of the patients were living 28 days—a standard indicator of long-term survival—after they began treatment with the combination.

The authors acknowledge that the number of patients included in the study is quite small and that they had to rely on the treating physician’s assessment of the drug combination’s effectiveness based on medical records. They comment, nevertheless, that Neutrexin and Leucovorin are a viable option for people who have failed or cannot tolerate Cotrimoxazole therapy.