Pregabalin for the Prevention of Oxaliplatin-Induced Painful Neuropathy: A Randomized, Double-Blind Trial

Lessons Learned.

Pregabalin is a medication that can decrease neuronal hyperexcitability, relieve neuropathic pain, and reach stable plasma levels after a titration period of only a few days.

Its use during oxaliplatin infusions was not able to decrease the incidence of chronic, oxalipaltin‐related neuropathic pain, compared with placebo.

Background.

Patients with colorectal cancer (CRC) receiving oxaliplatin (OXA) develop acute and chronic painful oxaliplatin‐induced peripheral neuropathy (OXAIPN). Acute and chronic OXA‐related neuropathies have different pathophysiological bases, but both lead to a common phenomenon: central sensitization (CS) of nociceptive neuronal networks, leading to increased sensitivity (hyperlgesia, allodynia) in the somatosensory system, the common ground of chronic neuropathic pain. Because CS is related to increased risk of painful OXAIPN, we hypothesized that preemptive use of the anti‐hyperalgesic drug pregabaline (known to decrease CS) during OXA infusions would decrease the incidence of chronic OXAIPN.

Methods.

Pain‐free, chemotherapy‐naïve CRC patients receiving at least one cycle of modified‐FLOX [5‐FU(500 mg/m²)+leucovorin(20 mg/m²)/week for] 6 weeks+oxaliplatin(85 mg/m²) at weeks 1‐3‐5 every 8 weeks] were randomized (1:1) into the study. Patients received either pregabalin or placebo for 3 days before and 3 days after each OXA infusion and were followed for up to 6 months. Clinical assessments were performed at baseline, at the end of chemotherapy, and after the follow‐up period. The main outcome was average pain at the last visit assessed by the visual analogic scale (0–10) item of the Brief Pain Inventory (BPI). Secondary endpoints were presence of neuropathic pain according to the Douleur Neuropathique‐4 (DN‐4), pain dimensions (short‐ form McGill Pain Questionnaire [MPQ]), Neuropathic Pain Symptom Inventory (NPSI), and changes in nerve conduction studies (NCS) and side effect profile.

Results.

One hundred ninety‐nine patients (57.0 ± 10.7 years old, 98 female, 101 male) were randomized. Data from 56 patients were not included in the analyses (as they did not receive at least one full cycle of modified FLOX). Data from 78 patients in the pregabalin group and 65 patients in the placebo group were retained for analyses. At the last visit, pain intensity in the pregabalin group was 1.03 (95% confidence interval [CI] = 0.79–1.26), and 0.85 (95% CI = 0.64–1.06) in the placebo group, which did not reach significance. Scores from the BPI, MPQ, DN‐4, NPSI, and NCS and side‐effect profiles and incidence of death did not differ between groups. Quality of life (QoL) score did not differ between groups (placebo = 76.9 ± 23.1, pregabalin group 79.4 ± 20.6). Mood scores were not significantly different between groups (placebo 9.7 [8.1–11.2]; pregabalin 6.8 [5.6–8.0]).

Conclusion.

The preemptive use of pregabalin during OXA infusions was safe, but did not decrease the incidence of chronic pain related to OXAIPN.

Phase II trial of metformin and paclitaxel for patients with gemcitabine-refractory advanced adenocarcinoma of the pancreas

BACKGROUND

In patients with adenocarcinoma of the pancreas, there are no standard second-line regimens. Many pre-clinical studies have shown that metformin alone or when combined with paclitaxel has antitumour effects on this tumour. We have tested here the combination of paclitaxel and metformin for patients with gemcitabine-refractory pancreatic cancer.

METHODS

An uncontrolled phase II trial was carried out based on a two-stage Simon's design, with metformin and paclitaxel for patients with locally advanced or metastatic pancreatic cancer whose disease had progressed during first line treatment with a gemcitabine-based regimen. The primary endpoint was the disease control rate at eight weeks as per response evaluation criteria in solid tumours (RECIST) 1.1. Patients received paclitaxel 80 mg/m(2) weekly for three weeks every 28 days and metformin 850 mg p.o. t.i.d. continuously until progression or intolerance state was reached.

RESULTS

Twenty patients were enrolled from July 2011 to January 2014: N = 6 (31.6%) achieved the primary endpoint, with all presenting stable disease. Median overall survival (OS) was 128 days (range 17-697) and the median progression free survival (PFS) was 44 days (range 14-210). Eight patients (40%) presented treatment-related G3-4 toxicities with the most common one being diarrhoea.

CONCLUSIONS

Despite the encouraging pre-clinical evidence of the antitumour activity of metformin in adenocarcinoma of the pancreas, the primary endpoint of the disease control rate was not met. Besides, the treatment combination was poorly tolerated and could not be studied further. This study highlights the importance of performing clinical trials to reassure preclinical or observational data.