The Recombinant Vaccine against Human Chorionic Gonadotropin goes on Combined Immunogenicity, Safety and Efficacy Clinical Trials

A chemically synthesized vaccine inducing antibodies against human chorionic gonadotropin (hCG) was previously developed by et al. [1] which had undergone successfully Phase I and Phase II efficacy Clinical trials in sexually active women showing its ability to prevent pregnancy without derangement of ovulation,hormonal profiles and menstrual regularity (Table 1). It had high efficacy with only one pregnancy occurring in 1224 cycles. It was fully reversible and women desirous of having another child conceived readily on antibodies falling below 20ng/ ml binding capacity [2]. The progeny born to previously immunized women had developmental land marks and cognitive abilities similar to their siblings [3].


Global Journal of Reproductive Medicine
Mumbai.The vaccine was found fully safe.8/9 immunized marmosets were protected from becoming pregnant on co-habitation with fertile males, whereas all non-immunized marmosets in the control group became pregnant.

Toxicology
Being a recombinant vaccine, its approval had to be obtained from Review Committee on Genetic Manipulation (RCGM), the National Committee for recombinant products.They demanded extensive toxicology on this vaccine from an independent GLP company.This was duly done by M/s Bioneeds at their GLP Facility in Bangalore, India.Both DNA and protein forms of the vaccine were non-sensitizing to the skin of guinea pigs with no clinical signs of toxicity, mortality and changes in body weight.Both were observed at even the highest dose tested.Repeat doses of the vaccine were also tested in rats, which were followed up to 90 days post immunization.These studies showed no treatment related changes in physical, physiological, clinical, hematological parameters, as also in histopathology profiles of the organs.
Segment II studies in rats showed that vaccines did not affect the embryo-foetal development.Body weight, food consumption, gross pathology remained normal, and no abnormal effect was observed in fetal sex ratio, fetal weight, external, visceral and skeletal norms of fetuses [8] (Table 1).

Approval by RCGM and DCGI
After obtaining the approval of RCGM, we applied for the approval of the Drugs Controller General of India for conducting clinical trials on a protocol which proposed immunogenicity studies at 100, 200, 300, 400 and 500 µg dose of the protein form of the vaccine after priming with 2 doses of 1.5mg of the DNA vaccine.The study will be carried out in 50 women of reproductive age and proven fertility, 10 women at 100 µg, 10 at 200 µg, 10 at 300 µg, 10 at 400 µg and 10 at 500 µg dose of the protein vaccine.A range of parameters will be analyzed before and after immunization.All important laboratory investigations such as anti-hCGtiters, haematological parameters, lipid profile, liver function tests, kidney function tests, serum calcium and phosphorus, total protein, albumin, globulin, progesterone, TSH, prolactin, estrogen, auto antibodies, etc. will be carried out.The trials will be carried out at the reputed institutes, the All India Institute of Medical Sciences, New Delhi and Sir Gangaram Hospital, New Delhi.Subjects will also be clinically examined for weight, blood pressure, androgenism, pelvic TVS ultrasound, pyrexia, H/O joint pains, local reaction at the site of injection, persistent pain at the site of injection and swelling, if any.On completion of these studies satisfactorily, 70 women of proven fertility will be enrolled for efficacy studies.They would be immunized with 2 doses of 1.5 mg of DNA form of the recombinant vaccine at 15 days interval followed by 2 injections of the protein form of the vaccine at the optimal dose determined in earlier phase of the trial.The IUDs will be removed and sexually active women will be observed for a period up to one year for remaining protected against pregnancy during the period, when antibody titers are above 50ng/ml hCG binding capacity.

Figure 1 :
Figure 1: Conceptualized structure of hCGβ-LTB vaccine.The carrier B chain of heat labile enterotoxin of E. coli (LTB) is fused at C-terminal glutamine of hCGβ.

Figure 2 :
Figure 2: Antibody titers in Balb/C mice immunized with hCGβ-LTB.Titers in each mouse are represented by different symbols.Bars represent the geometric means at various times following immunization.
vaccines were non-mutagenic at the highest concentration tested by Bacterial Reverse Mutation and Mammalian Chromosome Aberration Tests.Similar observation on non-mutagenic property of the vaccines was made in vivo by Mammalian Erythrocyte Micronucleus Test in Mice.Single dose acute toxicity study was conducted in Sprague Dawley rats.Vaccinated rats were observed for mortality, clinical signs of toxicity, body weight and gross pathological examination.No mortality, clinical signs of toxicity and treatment related changes in the body weight, were How to cite this article: Talwar G, Radhey S S, Jagdish C G, Kripa N N, Bandivdekar A et.al.The Recombinant Vaccine against Human Chorionic Gonadotropin goes on Combined Immunogenicity, Safety and Efficacy Clinical Trials.Glob J Reprod Med.2018; 5(1): 555654.DOI: 10.19080/ GJORM.2018.05.555654 003 Global Journal of Reproductive Medicine observed.No changes in gross pathology (external and internal)

Figure 3 :
Figure 3: Effect of DNA priming on antibody titers in Balb/C mice.(A) Anti hCG antibodies after 3 injections of proteinic form of the vaccine administered intra-muscularly.(B) Anti hCG antibodies titers in mice primed twice with DNA form of the recombinant hCGβ-LTB vaccine followed by the 3rd injection with proteinic form of the vaccine.Symbols represent the individual values, while bars give the geometric mean at various time points post immunization.On day 60, the antibody titers in 35 out of 40 mice were higher than the scale.

Table 1 :
Efficacy of HSD-TT/DT vaccine to prevent Pregnancy.