Monitoring treatment of colorectal cancer patients with drugs targeting EGFR pathway using mass spectrometry of patient samples

A method of facilitating treatment of a colorectal cancer (CRC) patient comprising the steps of:

• 1) assigning a baseline class label for the patient using a classifier operating on integrated intensity values at pre-defined m/z ranges in mass-spectral data obtained from a blood-based sample of the patient and a training set comprising class-labeled spectra from other patients, the baseline class label indicating whether the patient is likely to benefit from administration of a drug targeting an epidermal growth factor receptor pathway, wherein if the baseline class label is “good” (or the equivalent), the drug is administered to the patient;
• and
• 2) thereafter, while the patient is being treated with the drug, a) obtaining a mass spectrum of a blood-based sample of the patient, b) performing one or more predefined pre-processing steps on the mass spectrum, c) obtaining integrated intensity values of selected features in said spectrum at one or more pre-defined m/z ranges after the pre-processing steps on the mass spectrum have been performed, and d) assigning a further class label for the sample using the classifier and the training set, the further class label indicating whether the patient has developed a non-responsiveness to the treatment with the said drug.