The major problem here is that the proteins with a short half lives are not orally active and are not absorbed properly.
An orally active protein should be metabolically stable and have a longer half life, so that it is not degraded fast and absorbed efficiently.
To make orally active protein drug, the site directed mutagenesis can be used to redesign their genes for the expression of a modified peptide.

Drug PTC, 124 is taken orally while gene therapy requires the delivery of gene by vectors into respiratory tract. PTC 124 can be self administered while gene therapy requires proper medical treatment monitored by professionals. PTC 124 is readily taken up by cells while gene by vector system may be poorly or partially taken up by few cells.PTC 124 may have fewer or no side effects while gene therapy has possibility of side effects, i.e. viral vectors may cause infections.

Hormone insulin is synthesized as a proinsulin which consists of three polypeptide chains.It undergoes a process of maturation during which the chain C consisting of 33 amino acids is removed.The mature insulin molecule consists of two short polypeptide chains of about 51 amino acids.The chain A has 21 and the chain B has 30 amino acids which are linked together by disulphide bridges.

The best possible remedial measure is gene therapy in which a defective gene is manipulated by introduction of normal healthy and functional gene/s.

A diagnostic technique helps to identify or confirm a disorder.
e.g., ELISA is used to diagnose HIV infection.
A therapeutic agent is used to help in the treatment of a disease.
e.q., \(\alpha \)-1 antitrypsin is used to treat emphysema.