Loss of POLE3-POLE4 unleashes replicative gap accumulation upon treatment with PARP inhibitors.

The advent of PARP inhibitors (PARPis) has profoundly changed the treatment landscape of BRCA1/BRCA2-mutated cancers. Despite this, the development of resistance to these compounds has become a major challenge. Hence, a detailed understanding of the mechanisms underlying PARPi sensitivity is crucially needed. Here, we show that loss of the POLE3-POLE4 subunits of DNA polymerase epsilon (Polε) strongly sensitizes cancer cells to PARPis in a Polε level-independent manner. Loss of POLE3-POLE4 is not associated with defective RAD51 foci formation, excluding a major defect in homologous recombination. On the contrary, treatment with PARPis triggers replicative gap accumulation in POLE3-POLE4 knockout (KO) cells in a PRIMPOL-dependent manner. In addition to this, the loss of POLE3-POLE4 further sensitizes BRCA1-silenced cells to PARPis. Importantly, the knockdown of 53BP1 does not rescue PARPi sensitivity in POLE3-POLE4 KO cells, bypassing a common PARPi resistance mechanism and outlining a potential strategy to sensitize cancer cells to PARPis.

Long-Term Effect of Switching From an Anti-CGRP Receptor to an Anti-CGRP Ligand Antibody in Treatment-Refractory Chronic Migraine: A Prospective Real-World Analysis.

In migraine patients with a poor response to a calcitonin gene-related peptide monoclonal antibody against the receptor, switching to a calcitonin gene-related peptide monoclonal antibodies against the ligand may be beneficial. This was a long-term real-world prospective analysis conducted in treatment-refractory chronic migraine patients coming from two large tertiary referral headache centres, who did not achieve a meaningful response to erenumab and were switched to fremanezumab. Responders to fremanezumab were considered those who achieved at least 30% reduction in monthly migraine days by month 3, compared to the post-erenumab baseline. Secondary efficacy and disability outcomes were analysed. Thirty-nine patients (female n = 32, 82.1%; median age: 49 years old, IQR = 29.0-56.0) were included. After three months of treatment with fremanezumab, ten out of 39 patients (25.6%) were considered responders. Four of the 11 patients who continued fremanezumab became responders at month 6, increasing the number of responders to 14 patients (35.9%). Responders received a median of 12 injections (IQR = 9.0-18.0) at the time of the analysis. After the last treatment, 13 patients (33.3%) remained responders. The number of mean monthly migraine days significantly decreased from 21.4 at baseline (IQR = 10.7-30.0) to 8.6 (IQR = 3.8-13.9) at the last follow-up. Painkillers intake and HIT-6 score were significantly reduced at the last follow-up. About 1/3 of patients with treatment refractory chronic migraine who have a disappointing response to erenumab and switch to fremanezumab, obtained a meaningful and sustained improvement of their migraine load over time, supporting the appropriateness of this therapeutic approach in clinical practice.

Two-year effectiveness of erenumab in resistant chronic migraine: a prospective real-world analysis.

BACKGROUND: Controlled and real-world evidence have demonstrated the efficacy of calcitonin gene related peptide (CGRP) monoclonal antibodies (MABs) in migraine. However, data on the over-one-year sustained effectiveness of CGRP MABs in resistant chronic migraine (CM) is sparse.  METHODS: This is a two-year real-world prospective analysis of an ongoing single centre audit conducted in patients with resistant CM. Patients received monthly erenumab for six months before assessing its effectiveness. Responders were considered those who achieved at least 30% reduction in monthly migraine days (MMD) by month 6, compared to baseline. Secondary outcomes were also analysed, including changes of the Headache Impact Test version 6 (HIT-6). RESULTS: One hundred sixty-four patients [135 (82.3%) females; mean age 46 SD 14) years] were included in the audit and 160 patients analysed. Patients had failed a mean of 8.4 preventive treatments at baseline. At month 6, 76 patients (48%) were 30% responders to erenumab, 50 patients (31%) were 50% responders and 25 (15%) were 75% responders. The mean reduction in MMD at month 6 was 7.5 days compared to baseline (P < 0.001). At month 12 and month 18, 61 patients (38%) and 52 patients (33%) remained 30% responders respectively. At month 24, 36 patients (23%) remained 30% responders, 25 patients (16%) and 13 patients (8%) were respectively 50% and 75% responders. Compared to 95% of patients at baseline, at months 6, 12 and 24, 46%, 29% and 16% of responders respectively had severe disability. At least one adverse event at month 6, 12, 18 and 24 was reported by 49%, 19%, 11% and 3% of patients. By month 6, 13% of patients discontinued the treatment because of side effects, often constipation. CONCLUSIONS: Long-term sustained effectiveness of erenumab was reported only by a minority of resistant CM patients. Although more research in resistant migraine is needed, Erenumab can provide long-term meaningful reduction in migraine load and migraine-related disability in some patients.

Disrupted control of origin activation compromises genome integrity upon destabilization of Polε and dysfunction of the TRP53-CDKN1A/P21 axis.

The maintenance of genome stability relies on coordinated control of origin activation and replication fork progression. How the interplay between these processes influences human genetic disease and cancer remains incompletely characterized. Here we show that mouse cells featuring Polε instability exhibit impaired genome-wide activation of DNA replication origins, in an origin-location-independent manner. Strikingly, Trp53 ablation in primary Polε hypomorphic cells increased Polε levels and origin activation and reduced DNA damage in a transcription-dependent manner. Transcriptome analysis of primary Trp53 knockout cells revealed that the TRP53-CDKN1A/P21 axis maintains appropriate levels of replication factors and CDK activity during unchallenged S phase. Loss of this control mechanism deregulates origin activation and perturbs genome-wide replication fork progression. Thus, while our data support an impaired origin activation model for genetic diseases affecting CMG formation, we propose that loss of the TRP53-CDKN1A/P21 tumor suppressor axis induces inappropriate origin activation and deregulates genome-wide fork progression.

A prospective real-world analysis of erenumab in refractory chronic migraine.

BACKGROUND: Clinical trials have shown the safety and clinical superiority of erenumab compared to placebo in chronic migraine (CM). The aim of this analysis is to evaluate the effectiveness and tolerability of erenumab in a real-world setting in patients with refractory CM. METHODS: This is a prospective single centre real-world audit conducted in patients with CM with and without medication overuse, refractory to established preventive medications, who received monthly erenumab for 6 months. RESULTS: Of 164 patients treated, 162 patients (female = 135, mean age 46 ± 14.3 years old) were included in the audit. Patients had failed a mean of 8.4 preventive treatments at baseline and 91% of patients failed Botulinum toxin type A at baseline. The mean reduction in monthly migraine days was 6.0 days at month 3 (P = 0.002) and 7.5 days at month 6 (P < 0.001) compared to baseline. The mean reduction in monthly headache days was 6.3 days (P < 0.001) at month 3 and 6.8 days (P < 0.001) at month 6. At month 3, 49%, 35% and 13% and at month 6, 60%, 38% and 22% of patients obtained at least a 30%, 50% and 75% reduction in migraine days, respectively. The percentage of patients with medication overuse was reduced from 54% at baseline to 20% at month 3 and to 25% at month 6. Compared to baseline, the mean reduction of Headache Impact Test-6 score was 7.7 points at month 3 (from 67.6 ± 0.4 to 59.9 ± 0.9) (P < 0.001) and of 7.5 points at month 6 (60.1 ± 1.3) (P = 0.01). The percentage of patients with severe headache-related disability (HIT-6: 60-78) was reduced from 96% at baseline to 68% after three monthly treatments and to 59% after six treatments. At least one side effect was reported by 48% of patients at month 1, 22% at month 3 and 15% at month 6. Constipation (20%) and cold/flu-like symptoms (15%) were the most frequent adverse events reported. CONCLUSION: Erenumab may be an effective and well tolerated therapy for medically refractory CM patients with and without medication overuse.

Analgesic reduction during an interdisciplinary pain management programme: treatment effects and processes of change.

Long-term use of opioid medication is associated with a host of negative effects on health and quality of life. Guidelines state that people with chronic pain taking high doses of opioids without benefit should be supported to discontinue them. Little research has investigated psychological processes associated with analgesic use and tapering. This study investigated (1) analgesic use pre- and post-participation in an interdisciplinary pain management programme and its relationship to functioning and (2) psychological processes associated with analgesic use. Opioid use was associated with poorer functioning at baseline. Participating in an interdisciplinary pain management programme was associated with reductions in opioid dose and number of classes of analgesics used. Reductions in analgesic use were associated with improvements in functioning. Psychological inflexibility was associated with using higher doses of opioid medication and with using a greater number of classes of analgesics. Psychological flexibility appears relevant in explaining analgesic use. Future research could focus on targeting this process to improve tapering outcomes.