For bioequivalence studies, is principal investigator -  a medically qualified person - responsible for bioanalytical lab/PK/statistics?

For bioequivalence, responsibility for clinical, lab and statistics would rest with personnel qualified in the respective fields. The US FDA’s Compliance Program Guidance Manual for FDA Staff for Bioresearch Monitoring Human Drugs in Vivo Bioequivalence mentions as follows:

The clinical investigator in a bioequivalence study is involved in the screening and dosing of human subjects, and will ordinarily be a physician Ph. D., clinical pharmacologists and Pharm. Ds are acceptable if a physician is available to cover medical emergencies. The clinical investigator may also perform pharmacodynamic measurement(s) and evaluation activities of clinical or pharmacological endpoints.
The analytical investigator in a bioequivalence study is the scientist in the analytical facility responsible for assay development and validation, and analyses of biological specimens.

We want sites to send letters to subjects who do not return for study visits. Do these letters have to be approved by Ethics Committee?

To decide whether written communications to already enrolled subjects require EC review and approval, the EC should consider whether such communications would affect the rights and welfare of the subject. Any written communications that does not any effect on the conduct of the trial, its underlying science or methodology, associated risks and benefits, or the willingness of trial participants  to continue participation would not require prior review and approval by the EC. Based on these considerations, it appears that letters to subjects, to remind them to return for study visits would not require EC review and approval prior to use, provided such letters do not include any new information.

Are there regulations and/or guidance for data reported in the eCRF requiring supporting source documentation. If an adverse event (AE) is reported in the eCRF with no source documentation, would this be considered a deviation by regulatory authorities?

Adverse events need to be documented, assessed by the investigator, and reported to the sponsor, EC and regulatory authorities. Hence, adequate source documentation of critical information e.g. patient info, dates, severity, relationship to investigational product etc should be available. It is possible to provide additional documentation in paper format as to how the AE was discovered and assessed.

For electronic source data are used, US FDA has guidance for Electronic Source Data in Clinical Investigations. The guidance describes the electronic source data origination, source data capture, data element identifiers, modifications and corrections, use of electronic prompts, flags, and data quality checks in the eCRF, data review, and retention of records and data access.

An electronic data capture system for FDA-regulated studies should be Part 11 compliant.

What would be acceptable as current CV?

The sponsor is required to obtain curriculum vitae of the investigator showing the education, training, and experience that qualifies the investigator as an expert in the clinical trial of the investigational product. The regulations or guidelines do not specify a requirement to update the CV. However, regulators do expect an investigator to be in compliance with any laws or requirements, which are essential for qualifications as a medical practitioner.  Therefore, an investigator has to maintain a medical council of India license that is necessary to perform the clinical study e.g. to diagnose or treat a patient). If the license is subject to renewal, then a current license would be required in order to be compliant with the Indian GCP requirements.

Is it acceptable for a principal investigator (PI) to be away from site for several months and still fulfill the requirements to supervise a study as the PI?

The regulatory authorities would not accept a situation where PI, who is overseeing a clinical Trail, is not on site to oversee the study. The regulations require that sponsors select investigators who can commit themselves to personally conduct or supervise the investigation. As PI is responsible for overseeing the clinical trial at his/her site and ensuring protection of the rights, safety and welfare of subjects, and providing reasonable medical care for study participants for medical problems arising during the trial. The PI cannot fulfill such obligations if he/she is away from site for some time.